thermomechanical fatigue life prediction for a marine
TRANSCRIPT
Washington University School of Medicine Washington University School of Medicine
Digital CommonsBecker Digital CommonsBecker
Open Access Publications
2014
Thermomechanical fatigue life prediction for a marine diesel Thermomechanical fatigue life prediction for a marine diesel
engine piston considering ring dynamics engine piston considering ring dynamics
Tao He Washington University School of Medicine in St Louis
Xiqun Lu Harbin Engineering University
Dequan Zou Washington University School of Medicine in St Louis
Yibin Guo Harbin Engineering University
Wanyou Li Harbin Engineering University
See next page for additional authors
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Recommended Citation Recommended Citation He Tao Lu Xiqun Zou Dequan Guo Yibin Li Wanyou and Huang Minli Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics Advances in Mechanical Engineering 2014 1-10 (2014) httpsdigitalcommonswustleduopen_access_pubs3697
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Authors Authors Tao He Xiqun Lu Dequan Zou Yibin Guo Wanyou Li and Minli Huang
This open access publication is available at Digital CommonsBecker httpsdigitalcommonswustleduopen_access_pubs3697
Research ArticleThermomechanical Fatigue Life Prediction for a Marine DieselEngine Piston considering Ring Dynamics
Tao He12 Xiqun Lu1 Dequan Zou12 Yibin Guo1 Wanyou Li1 and Minli Huang3
1 College of Power and Energy Engineering Harbin Engineering University Harbin Heilongjiang 150001 China2Washington University in St Louis St Louis MO 63108 USA3 Parks College of Engineering Aviation and Technology Saint Louis University St Louis MO 63105 USA
Correspondence should be addressed to Xiqun Lu luxiqunhrbeueducn
Received 11 April 2014 Accepted 17 July 2014 Published 19 October 2014
Academic Editor Mustafa Canakci
Copyright copy 2014 Tao He et al This is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
A newly designed marine diesel engine piston was modeled using a precise finite element analysis (FEA) The high cycle fatigue(HCF) safety factor prediction procedure designed in this study incorporated lubrication thermal and structure analysisThepistonring dynamics calculation determined the predicted thickness of lubrication oil film The film thickness influenced the calculatedmagnitude of the heat transfer coefficient (HTC) used in the thermal loads analysis Moreover the gas pressure of ring lands andring grooves used in mechanical analysis is predicted based on the piston ring dynamics model
1 Introduction
The increasing demand for high power density low emissionand low fuel consumption engines impose many restrictionson the design of diesel engine components The piston isone of the most challenging components in diesel enginedesign Pistons are subjected to high thermal andmechanicalloads Large temperature difference between piston crownsand cooling galleries induce significant thermal loads Inaddition gas pressure and piston acceleration can developcyclic mechanical stresses which are superimposed on earlierthermal stressed components This cycle of thermal andmechanical stresses causes the thermomechanical fatigue thatis the main cause of failure in diesel engine pistons
In this study the authors focus on damage causedby fatigue This damage is created both by thermal andmechanical stresses [1] To improve the life and reliabilityof pistons a large number of fatigue tests are carried outwhen designing new pistons [2ndash4] However to reduce thecost and time involved in fatigue testing many engine man-ufactures use FEA to predict the distribution of temperatureand stress on engine components The fast development ofthe numerical calculating technology has allowed FEA tobecome a significant tool in mechanical dynamics analysis
thermal analysis and thermomechanical coupling analysis ofnew piston designs [5ndash8] and in thermomechanical fatigueanalysis [9] Under thermomechanical fatigue loading pistonfailure may occur due to fatigue material degradation due toenvironmental influence (oxidation) and creep mechanisms[10] Thermomechanical fatigue life assessment methods canbe classified as empirical methods fracture mechanics the-ories continuum mechanical models and models based onmicrostructure [11] Empirical models correlate the numberof cycles to failure to parameters of the hysteresis loop forexample stress strain and plastic strain [12]
In this study a three-dimensional FEA is used to predictthe thermomechanical behavior of a newly designed dieselmarine engine piston In order to accurately determine theheat transfer coefficient (HTC) of the piston head the oilfilm is taken into consideration in the thermal analysis Thethicknesses of oil film between ringpiston and ringbore aredetermined using a ring pack lubrication model To calculatethe oil pressure distribution in the piston landsgroovesoperation a piston ring dynamics model is used in themechanical loads analysis The coupled actions of thermalloads and mechanical loads (including combustion pressureinertial load and oil pressure in ring landsgrooves) are usedto predict fatigue life The prediction procedure designed
Hindawi Publishing CorporationAdvances in Mechanical EngineeringVolume 2014 Article ID 429637 10 pageshttpdxdoiorg1011552014429637
2 Advances in Mechanical Engineering
Connecting bolt
Piston headSkirtPin
RodConnecting rodsmall end bush
(a) Solid model of piston (b) FE model of piston
Figure 1 The solid and FE model of the piston
Table 1 Engine parameters and piston materials
Design structure CompositeDiameter of bore (mm) 270Max combustion pressure (MPa) 23Rated power (KW) 455Rated speed (rpm) 1000Stroke (mm) 330Material of head 42CrMoAMaterial of skirt QT700-2Material of bolt 18Cr2Ni4WAMaterial of pin 12CrNi4A
in this study is the combination of lubrication analysis andstructure analysis The results obtained by this new methodwill provide a guideline for further optimizing piston design
2 The Finite Element Model
Due to the symmetrical structure of the piston a 14 3Dsolid model (Figure 1(a)) including piston pin and rodwas created The FE software ANSYS was used for FEAin this study For the FE model 3D 8-node solid elementssolid45 was chosen to perform the thermomechanical cou-pled analysis As shown in Figure 1(b) 37246nodes and 60638elements were obtained The materials of each part are listedin Table 1 Since this study focuses on the piston propertiesthe connection rod is set as a rigid body for analysis
The surface-surface contact unit is placed on the contactsurface between the piston pin hole and the piston pin headand skirt head and bolt skirt and bolt pin and bush pin andskirt and bush and rod Figure 2 shows the contact pairs inthis piston model
Bush-rod
Pin-bush
Pin-skirt
Skirt-bolt
Head-skirt
Head-bolt
Figure 2 The contact pairs distribution in the piston model
3 Theory
31 Thermal Boundary Conditions Piston temperature isusually considered to be independent of the operating statesand remains constant during a working cycle [13] Sincethe time response of piston material to the variation ofboundary conditions in a firing cycle is very slow a steadystate thermal analysis has been done considering the typicalvalues of temperatures and heat transfer coefficients at pistonboundary surfaces during one firing cycle Based on thethird kind of steady-state heat conduction conductive heattransfer boundary condition is that the temperature of thefluid medium contacting to the objects and the heat transfercoefficient are known and can be shown as
119896120597119879
120597119899
10038161003816100381610038161003816100381610038161003816119910= 120572 (119879 minus 119879119891)
10038161003816100381610038161003816119910 (1)
Advances in Mechanical Engineering 3
1600
1400
1200
1000
800
600
400
200
0 60 120 180 240 300 360 420 480 540 600 660 720
CA (deg)
6000
5000
4000
3000
2000
1000
00 100 200 300 400 500 600 700
CA (deg)
Tg
(K)
hg
(W(
m2
K))
Figure 3 ℎ119892 119879119892calculated by GT-Power
where 119879119891 is the medium temperature 120572 is the HTC and 119879119891can be constant or time and position variety as well as 120572 [14]
(1) HTC on Piston Top Surface Based on the assumption of asteady working state of the engine the average HTC and theaverage piston surface temperature in a whole working cyclecan be given as
ℎ119898 =1
720int
720
0
ℎ119892119889120593
119879res =1
720 sdot ℎ119898
int
720
0
ℎ119892119879119892119889120593
(2)
where ℎ119892 119879119892 are the instant HTC of gas at piston surface andinstant gas temperature According to the design parametersof the engine ℎ119892 and 119879119892 can be calculated by GT-Power(Figure 3) According to (2) ℎ119898 = 121488Wm2 K and119879res = 91331K
Using Sealrsquos formula and experimental data the HTC ofpiston head is the function of position in radial direction
If 119903 lt 119873 ℎ119903 =2ℎ119898
1 + 11989001119873151198900111990315
If 119903 ge 119873 ℎ119903 =2ℎ119898
1 + 119890011198731511989001(2119873minus119903)
15
(3)
where 119903 is the distance from a local point to the center axis ofthe piston head and 119873 is the distance from the point wherethe maximum temperature occurs to the center axis of thepiston For FEA modeling the top surface of the pistonis divided into 10 subregions radially Then based on thepistonrsquos structural parameters the HTC on the top of headcan be determined by (3) The HTC distribution of the tophead of the newly designed piston is shown in Figure 4
(2) HTC at Skirt and Cooling Oil Channels The currentanalysis used HTC values at the skirt and oil channels thatwere determined by Lu et al [14]Their analysis used a pistonwith a similar structure and size
00000 00267 00534 00801 01068 013350
500
1000
1500
2000H
eat t
rans
fer c
oeffi
cien
t(W
m2
K)
Figure 4 HTCs distribution at the top of piston head
(3) HTCs at Piston Ring LandsGrooveThe thermal transferprocess in piston ring landsgrooves is shown in Figure 5Figure 5(a) is the thermal resistance map from piston to borethrough ring land and Figure 5(b) is the thermal resistancemap from piston to bore through ring grooveThe resistancesin the transfer paths (Figure 5) have been specific by Luet al [15] Parameters such as the position of ring duringoperation and the thickness of oil film between ringboreand ringpiston are important in the heat transfer process Inorder to predict the magnitude of those parameters a ringdynamics analysis is applied in this study
(4) Ring Dynamics The motion of piston ring withinthe piston groove can be described by the axial rotational(torsional twist) and radial motions in the three respectivedegrees of freedom The ring motion in the circumferencedirection is neglected in this study A small section ofthe ring at a circumferential location is considered in theanalysis (Figure 6) The whole ring dynamic analysis modeldeveloped by Tian et al [16] is used in this study Consideringthe complexity of heat transfer and time consumption of
4 Advances in Mechanical Engineering
Ring
Piston
Bore
Piston landPiston groove
R1 R2 R3
Air between pistonland and bore
Film thicknesson the bore
Tpiston Twater
Oil film
Thickness of bore
(a) Resistance map of heat transfer in piston land
R4 R5 R6 R7
RingFilm thicknessof ringbore
Air between pistonland and bore
Tpiston TwaterThickness of bore
(b) Resistance map of heat transfer in piston groove
Figure 5 The resistance map of heat transfer from piston head to bore
r
y
120572
Ftension
Piston
Ring
Liner
Fgpre
Fgoil
Mgoil
Flpre
Mlpre
Fcfrc
Mcfrc
Mgasp
Fcasp
Flpre
hcg
Mgfrc Fgfrc
Pi
FcoilMcoil
Fgasp
Pi+1
cg (ycg)
Oil film
Figure 6 Free body diagram of ring cross section
simulation the section of thrust side (TS) is used Thegoverning equations for the ring motion are
119898119903
1198892119910cg
1198891199052= 119865119892oil + 119865119892asp + 119865119888frc minus 119865119897pre minus 119898119903119892
1198681199031198892120572
1198891199052= 119872119892oil +119872119892asp +119872119888frc +119872119897pre +119872119888oil
+119872119888asp minus 119870119903119905120572
119898119903
1198892ℎcg
1198891199052= 119865119892pre + 119865119892frc + 119865119888oil minus 119865119888asp
minus 1198651015840
119897pre + 119870119903119903 (ℎ1015840+ ℎ0)
(4)
where 119910cg and ℎcg are the axial and radial position of thecenter of gravity of the ring and120572 is the twist angle119898119903 119868119903 and119870119903119905 are ringmassmoment of inertia for toroidal rotation andcross-sectional torsional stiffness 119870119903119903 is the radial tensionstiffness ℎ1015840 is the reduction in ring radius at installation andℎ0 is the minimum ring-bore oil film thickness (119865tension =
119870119903119903(ℎ1015840+ ℎ0)) 119865 and119872 are the forces and moments acting on
the ring cross section (Figure 6) In (4) the first subscript forthe force and moment terms indicates location on the ring(119892 = groove 119888 = cylinder and 119897 = land) and the secondsubscript describes the source of the force or moment (oil =oil pressure asp = normal pressure due to asperity contactpre = gas pressure and frc = hydrodynamic or boundaryfriction) The torsional moment119872119903119905 is calculated as
119872119903119905 = 119870119903119905120572 (5)
For a complete ring with rectangular cross section the cross-sectional torsional stiffness (119870119903119905) is given by
119870119903119905 =1198641198873 ln (119863119889)3 (119863 + 119889)
(6)
where 119864 is the modulus of elasticity of piston ring 119887 is theaxial height of piston ring section 119889 is the inner diameterand 119863 is the outer diameter of piston ring The axial motionof a ring relative to piston can be expressed as
119910cg = 119910119901 + 119910119903119901
119889119910cg
119889119905=119889119910119901
119889119905+119889119910119903119901
119889119905
1198892119910cg
1198891199052=1198892119910119901
1198891199052+1198892119910119903119901
1198891199052
(7)
where 119910119901 is the axial position of the piston and 119910119903119901 is the axialposition of the ring related to the piston And 119910119901 can be given
Advances in Mechanical Engineering 5
52
Ges
chliff
en08 08
R04
R 04
3middot middot middot12 120583m3middot middot middot12120583m
45 ∘
30 ∘radicRz4
44middot middot middot66120583mradicRz 6Ground
R 03 max
R03
max
minus0005minus0050
First ring Second ringand third ring
Oil ring
04
max
04
max
35plusmn02
09 plusmn01
05plusmn005
145plusmn045
145plusmn045
02plusmn01
02plusmn01
45∘ plusmn5∘
45∘ plusmn5∘
35 ∘plusmn2 ∘
35∘ plusmn2∘
asymp35
3∘ plusmn 30998400
Figure 7 The geometry of the piston rings
out by the piston secondary motion together with the axialmotion Using a developed version of an existing ring packlubrication model Gamble et al [17] investigated the effectof piston secondary motion on the performance of a dieselengine piston ring pack in terms of gas flow and interringgas pressures For an example engine operating condition theeffect of secondarymotion on the ring packwas calculated fora number of ring gap positional combinationsThe secondarymotion and the positions of the ring gaps were shown to havean effect on the ring pack operating conditions such as oilfilm thickness friction wear oil transport and degradationAnd in order to determine the parameter 119910119901 the tilt of pistonand axial position are needed and those two parameters canbe calculated by iteration algorithm used in [17]
Forces and moment associated with land and groove gaspressure are calculated using pressure solutions from the gasdynamics submodel Forces and moments associated withoil pressure are obtained from the lubrication submodeland those associated with local asperity contact pressure arecalculated by asperity deformationmodel Ring axial positionand twist influence gas flow paths and the forces at the ring-groove interface Ring twist also affects the effective profilepresented by the ring face to the cylinder bore and thus affectsoil film thickness and ring friction The lubrication modelasperity deformation model and oil film squeezing model atring side and groove interface have been previously described[16 18]
The structure of the rings used in the piston is shownin Figure 7 Each ring is modeled as a single mass twisting(including pretwist angles) is considered The equations ofmotion which considers equilibrium condition of momentsand forces for each ring are solvedThe dynamic componentsof ringmotion are calculated using time integrationmethods
07
06
05
04
03
02
01
0
Hei
ght o
f bor
e (m
)
minus500E minus 05 500E minus 05 150E minus 04 250E minus 04
Deformation considering install prestressDeformation considering both of install prestress and thermalDeformation considering thermal
Deformation (m)
Figure 8 The bore deformation
The cylinder liner typically shows a deformation alongcylinder length axis and along cylinder circumference dueto bolting prestress and thermal load in the real conditionIn this study the deformation of bore in different caseshas been given by Figure 8 The mechanism of piston ringsealing is equivalent to a labyrinth seal where the gapclearances are determined by the position of the rings inthe groove considering the global movement and tilting ofthe piston [17] The Reynolds equations are solved iterativelyin each time step to determine the hydrodynamic pressuredistribution between ring running surface and liner All
6 Advances in Mechanical Engineering
0 90 180 270 360 450 540 630 720minus010
minus008
minus006
minus004
minus002
000
002
004
CA (deg)
Tilti
ng an
gle o
f pist
on (d
eg)
Figure 9 The tilting angle of piston during operation
minus008
minus006
minus004
minus002
000
002
004
006
008
First ring Second ring Oil ring
Crank angle (deg)0minus360 360
The p
ositi
on o
f rin
gs in
gro
ove (
mm
)
Figure 10 The position of rings in groove
relevant mechanisms are considered the calculation is donequasi-statically per time step The tilting angle of piston isgiven by Figure 9 And the motion of each ring in grooveduring operation is shown in Figure 10 and the thickness offilm oil between each ring face and bore is shown in Figure 11
32 Temperature Distribution Using the mathematicalmodel developed above the HTCs distribution in pistongrooveslands can be determined after getting the positionof each ring and the film thickness between each ring andbore Based on the determined HTCs in the top head pistonlandsgrooves and piston skirt the temperature distributionof the piston is predicted by FEA in ANSYS (Figures 12 and13) As shown in Figures 12 and 13 the temperature intensitydistribution decreases gradually from the head of the pistonto the bottom of the skirt A maximum temperature ofapproximately 392∘C is obtained on the head of the pistonat the combustion chamber chamfer edge (Figure 12) This
0 60 120 180 240 300 360 420 480 540 600 660 7200000
0005
0010
0015
0020
0025
Crank angle (deg)
Film
thic
knes
s (m
m)
First ringSecond ringOil ring
Figure 11 The film thickness of each ring
400350300250200
392∘CΔT
MX195∘C
156∘C134∘C
11689
4
147505
178116
208728
239339
269951
300562
331173
361785
392396
Figure 12 The temperature distribution of piston head
result is similar to that obtained on a similar type of pistonin an earlier study [19] The temperature decreases radicallytowards the outside and inside of piston The temperature is156∘C and 134∘C at the bottom of fire land and second landrespectively As it is shown in Figure 11 the temperaturedistribution in the skirt bolt and pin are lower than thepiston The maximum temperature is 1556∘C 250∘C and997∘C respectively
33TheMechanical Loads Theworking pistonnot only bearsa thermal load but also the high pressure of the fuel gasand the inertia force created by the reciprocating motionThe most strenuous condition of running the piston is themoment when the pressure in the combustion chamberreaches its maximum valueTherefore this study lays empha-sis on the stable stress at the combustion moment whenoperating at a stable speed
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
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- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
Authors Authors Tao He Xiqun Lu Dequan Zou Yibin Guo Wanyou Li and Minli Huang
This open access publication is available at Digital CommonsBecker httpsdigitalcommonswustleduopen_access_pubs3697
Research ArticleThermomechanical Fatigue Life Prediction for a Marine DieselEngine Piston considering Ring Dynamics
Tao He12 Xiqun Lu1 Dequan Zou12 Yibin Guo1 Wanyou Li1 and Minli Huang3
1 College of Power and Energy Engineering Harbin Engineering University Harbin Heilongjiang 150001 China2Washington University in St Louis St Louis MO 63108 USA3 Parks College of Engineering Aviation and Technology Saint Louis University St Louis MO 63105 USA
Correspondence should be addressed to Xiqun Lu luxiqunhrbeueducn
Received 11 April 2014 Accepted 17 July 2014 Published 19 October 2014
Academic Editor Mustafa Canakci
Copyright copy 2014 Tao He et al This is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
A newly designed marine diesel engine piston was modeled using a precise finite element analysis (FEA) The high cycle fatigue(HCF) safety factor prediction procedure designed in this study incorporated lubrication thermal and structure analysisThepistonring dynamics calculation determined the predicted thickness of lubrication oil film The film thickness influenced the calculatedmagnitude of the heat transfer coefficient (HTC) used in the thermal loads analysis Moreover the gas pressure of ring lands andring grooves used in mechanical analysis is predicted based on the piston ring dynamics model
1 Introduction
The increasing demand for high power density low emissionand low fuel consumption engines impose many restrictionson the design of diesel engine components The piston isone of the most challenging components in diesel enginedesign Pistons are subjected to high thermal andmechanicalloads Large temperature difference between piston crownsand cooling galleries induce significant thermal loads Inaddition gas pressure and piston acceleration can developcyclic mechanical stresses which are superimposed on earlierthermal stressed components This cycle of thermal andmechanical stresses causes the thermomechanical fatigue thatis the main cause of failure in diesel engine pistons
In this study the authors focus on damage causedby fatigue This damage is created both by thermal andmechanical stresses [1] To improve the life and reliabilityof pistons a large number of fatigue tests are carried outwhen designing new pistons [2ndash4] However to reduce thecost and time involved in fatigue testing many engine man-ufactures use FEA to predict the distribution of temperatureand stress on engine components The fast development ofthe numerical calculating technology has allowed FEA tobecome a significant tool in mechanical dynamics analysis
thermal analysis and thermomechanical coupling analysis ofnew piston designs [5ndash8] and in thermomechanical fatigueanalysis [9] Under thermomechanical fatigue loading pistonfailure may occur due to fatigue material degradation due toenvironmental influence (oxidation) and creep mechanisms[10] Thermomechanical fatigue life assessment methods canbe classified as empirical methods fracture mechanics the-ories continuum mechanical models and models based onmicrostructure [11] Empirical models correlate the numberof cycles to failure to parameters of the hysteresis loop forexample stress strain and plastic strain [12]
In this study a three-dimensional FEA is used to predictthe thermomechanical behavior of a newly designed dieselmarine engine piston In order to accurately determine theheat transfer coefficient (HTC) of the piston head the oilfilm is taken into consideration in the thermal analysis Thethicknesses of oil film between ringpiston and ringbore aredetermined using a ring pack lubrication model To calculatethe oil pressure distribution in the piston landsgroovesoperation a piston ring dynamics model is used in themechanical loads analysis The coupled actions of thermalloads and mechanical loads (including combustion pressureinertial load and oil pressure in ring landsgrooves) are usedto predict fatigue life The prediction procedure designed
Hindawi Publishing CorporationAdvances in Mechanical EngineeringVolume 2014 Article ID 429637 10 pageshttpdxdoiorg1011552014429637
2 Advances in Mechanical Engineering
Connecting bolt
Piston headSkirtPin
RodConnecting rodsmall end bush
(a) Solid model of piston (b) FE model of piston
Figure 1 The solid and FE model of the piston
Table 1 Engine parameters and piston materials
Design structure CompositeDiameter of bore (mm) 270Max combustion pressure (MPa) 23Rated power (KW) 455Rated speed (rpm) 1000Stroke (mm) 330Material of head 42CrMoAMaterial of skirt QT700-2Material of bolt 18Cr2Ni4WAMaterial of pin 12CrNi4A
in this study is the combination of lubrication analysis andstructure analysis The results obtained by this new methodwill provide a guideline for further optimizing piston design
2 The Finite Element Model
Due to the symmetrical structure of the piston a 14 3Dsolid model (Figure 1(a)) including piston pin and rodwas created The FE software ANSYS was used for FEAin this study For the FE model 3D 8-node solid elementssolid45 was chosen to perform the thermomechanical cou-pled analysis As shown in Figure 1(b) 37246nodes and 60638elements were obtained The materials of each part are listedin Table 1 Since this study focuses on the piston propertiesthe connection rod is set as a rigid body for analysis
The surface-surface contact unit is placed on the contactsurface between the piston pin hole and the piston pin headand skirt head and bolt skirt and bolt pin and bush pin andskirt and bush and rod Figure 2 shows the contact pairs inthis piston model
Bush-rod
Pin-bush
Pin-skirt
Skirt-bolt
Head-skirt
Head-bolt
Figure 2 The contact pairs distribution in the piston model
3 Theory
31 Thermal Boundary Conditions Piston temperature isusually considered to be independent of the operating statesand remains constant during a working cycle [13] Sincethe time response of piston material to the variation ofboundary conditions in a firing cycle is very slow a steadystate thermal analysis has been done considering the typicalvalues of temperatures and heat transfer coefficients at pistonboundary surfaces during one firing cycle Based on thethird kind of steady-state heat conduction conductive heattransfer boundary condition is that the temperature of thefluid medium contacting to the objects and the heat transfercoefficient are known and can be shown as
119896120597119879
120597119899
10038161003816100381610038161003816100381610038161003816119910= 120572 (119879 minus 119879119891)
10038161003816100381610038161003816119910 (1)
Advances in Mechanical Engineering 3
1600
1400
1200
1000
800
600
400
200
0 60 120 180 240 300 360 420 480 540 600 660 720
CA (deg)
6000
5000
4000
3000
2000
1000
00 100 200 300 400 500 600 700
CA (deg)
Tg
(K)
hg
(W(
m2
K))
Figure 3 ℎ119892 119879119892calculated by GT-Power
where 119879119891 is the medium temperature 120572 is the HTC and 119879119891can be constant or time and position variety as well as 120572 [14]
(1) HTC on Piston Top Surface Based on the assumption of asteady working state of the engine the average HTC and theaverage piston surface temperature in a whole working cyclecan be given as
ℎ119898 =1
720int
720
0
ℎ119892119889120593
119879res =1
720 sdot ℎ119898
int
720
0
ℎ119892119879119892119889120593
(2)
where ℎ119892 119879119892 are the instant HTC of gas at piston surface andinstant gas temperature According to the design parametersof the engine ℎ119892 and 119879119892 can be calculated by GT-Power(Figure 3) According to (2) ℎ119898 = 121488Wm2 K and119879res = 91331K
Using Sealrsquos formula and experimental data the HTC ofpiston head is the function of position in radial direction
If 119903 lt 119873 ℎ119903 =2ℎ119898
1 + 11989001119873151198900111990315
If 119903 ge 119873 ℎ119903 =2ℎ119898
1 + 119890011198731511989001(2119873minus119903)
15
(3)
where 119903 is the distance from a local point to the center axis ofthe piston head and 119873 is the distance from the point wherethe maximum temperature occurs to the center axis of thepiston For FEA modeling the top surface of the pistonis divided into 10 subregions radially Then based on thepistonrsquos structural parameters the HTC on the top of headcan be determined by (3) The HTC distribution of the tophead of the newly designed piston is shown in Figure 4
(2) HTC at Skirt and Cooling Oil Channels The currentanalysis used HTC values at the skirt and oil channels thatwere determined by Lu et al [14]Their analysis used a pistonwith a similar structure and size
00000 00267 00534 00801 01068 013350
500
1000
1500
2000H
eat t
rans
fer c
oeffi
cien
t(W
m2
K)
Figure 4 HTCs distribution at the top of piston head
(3) HTCs at Piston Ring LandsGrooveThe thermal transferprocess in piston ring landsgrooves is shown in Figure 5Figure 5(a) is the thermal resistance map from piston to borethrough ring land and Figure 5(b) is the thermal resistancemap from piston to bore through ring grooveThe resistancesin the transfer paths (Figure 5) have been specific by Luet al [15] Parameters such as the position of ring duringoperation and the thickness of oil film between ringboreand ringpiston are important in the heat transfer process Inorder to predict the magnitude of those parameters a ringdynamics analysis is applied in this study
(4) Ring Dynamics The motion of piston ring withinthe piston groove can be described by the axial rotational(torsional twist) and radial motions in the three respectivedegrees of freedom The ring motion in the circumferencedirection is neglected in this study A small section ofthe ring at a circumferential location is considered in theanalysis (Figure 6) The whole ring dynamic analysis modeldeveloped by Tian et al [16] is used in this study Consideringthe complexity of heat transfer and time consumption of
4 Advances in Mechanical Engineering
Ring
Piston
Bore
Piston landPiston groove
R1 R2 R3
Air between pistonland and bore
Film thicknesson the bore
Tpiston Twater
Oil film
Thickness of bore
(a) Resistance map of heat transfer in piston land
R4 R5 R6 R7
RingFilm thicknessof ringbore
Air between pistonland and bore
Tpiston TwaterThickness of bore
(b) Resistance map of heat transfer in piston groove
Figure 5 The resistance map of heat transfer from piston head to bore
r
y
120572
Ftension
Piston
Ring
Liner
Fgpre
Fgoil
Mgoil
Flpre
Mlpre
Fcfrc
Mcfrc
Mgasp
Fcasp
Flpre
hcg
Mgfrc Fgfrc
Pi
FcoilMcoil
Fgasp
Pi+1
cg (ycg)
Oil film
Figure 6 Free body diagram of ring cross section
simulation the section of thrust side (TS) is used Thegoverning equations for the ring motion are
119898119903
1198892119910cg
1198891199052= 119865119892oil + 119865119892asp + 119865119888frc minus 119865119897pre minus 119898119903119892
1198681199031198892120572
1198891199052= 119872119892oil +119872119892asp +119872119888frc +119872119897pre +119872119888oil
+119872119888asp minus 119870119903119905120572
119898119903
1198892ℎcg
1198891199052= 119865119892pre + 119865119892frc + 119865119888oil minus 119865119888asp
minus 1198651015840
119897pre + 119870119903119903 (ℎ1015840+ ℎ0)
(4)
where 119910cg and ℎcg are the axial and radial position of thecenter of gravity of the ring and120572 is the twist angle119898119903 119868119903 and119870119903119905 are ringmassmoment of inertia for toroidal rotation andcross-sectional torsional stiffness 119870119903119903 is the radial tensionstiffness ℎ1015840 is the reduction in ring radius at installation andℎ0 is the minimum ring-bore oil film thickness (119865tension =
119870119903119903(ℎ1015840+ ℎ0)) 119865 and119872 are the forces and moments acting on
the ring cross section (Figure 6) In (4) the first subscript forthe force and moment terms indicates location on the ring(119892 = groove 119888 = cylinder and 119897 = land) and the secondsubscript describes the source of the force or moment (oil =oil pressure asp = normal pressure due to asperity contactpre = gas pressure and frc = hydrodynamic or boundaryfriction) The torsional moment119872119903119905 is calculated as
119872119903119905 = 119870119903119905120572 (5)
For a complete ring with rectangular cross section the cross-sectional torsional stiffness (119870119903119905) is given by
119870119903119905 =1198641198873 ln (119863119889)3 (119863 + 119889)
(6)
where 119864 is the modulus of elasticity of piston ring 119887 is theaxial height of piston ring section 119889 is the inner diameterand 119863 is the outer diameter of piston ring The axial motionof a ring relative to piston can be expressed as
119910cg = 119910119901 + 119910119903119901
119889119910cg
119889119905=119889119910119901
119889119905+119889119910119903119901
119889119905
1198892119910cg
1198891199052=1198892119910119901
1198891199052+1198892119910119903119901
1198891199052
(7)
where 119910119901 is the axial position of the piston and 119910119903119901 is the axialposition of the ring related to the piston And 119910119901 can be given
Advances in Mechanical Engineering 5
52
Ges
chliff
en08 08
R04
R 04
3middot middot middot12 120583m3middot middot middot12120583m
45 ∘
30 ∘radicRz4
44middot middot middot66120583mradicRz 6Ground
R 03 max
R03
max
minus0005minus0050
First ring Second ringand third ring
Oil ring
04
max
04
max
35plusmn02
09 plusmn01
05plusmn005
145plusmn045
145plusmn045
02plusmn01
02plusmn01
45∘ plusmn5∘
45∘ plusmn5∘
35 ∘plusmn2 ∘
35∘ plusmn2∘
asymp35
3∘ plusmn 30998400
Figure 7 The geometry of the piston rings
out by the piston secondary motion together with the axialmotion Using a developed version of an existing ring packlubrication model Gamble et al [17] investigated the effectof piston secondary motion on the performance of a dieselengine piston ring pack in terms of gas flow and interringgas pressures For an example engine operating condition theeffect of secondarymotion on the ring packwas calculated fora number of ring gap positional combinationsThe secondarymotion and the positions of the ring gaps were shown to havean effect on the ring pack operating conditions such as oilfilm thickness friction wear oil transport and degradationAnd in order to determine the parameter 119910119901 the tilt of pistonand axial position are needed and those two parameters canbe calculated by iteration algorithm used in [17]
Forces and moment associated with land and groove gaspressure are calculated using pressure solutions from the gasdynamics submodel Forces and moments associated withoil pressure are obtained from the lubrication submodeland those associated with local asperity contact pressure arecalculated by asperity deformationmodel Ring axial positionand twist influence gas flow paths and the forces at the ring-groove interface Ring twist also affects the effective profilepresented by the ring face to the cylinder bore and thus affectsoil film thickness and ring friction The lubrication modelasperity deformation model and oil film squeezing model atring side and groove interface have been previously described[16 18]
The structure of the rings used in the piston is shownin Figure 7 Each ring is modeled as a single mass twisting(including pretwist angles) is considered The equations ofmotion which considers equilibrium condition of momentsand forces for each ring are solvedThe dynamic componentsof ringmotion are calculated using time integrationmethods
07
06
05
04
03
02
01
0
Hei
ght o
f bor
e (m
)
minus500E minus 05 500E minus 05 150E minus 04 250E minus 04
Deformation considering install prestressDeformation considering both of install prestress and thermalDeformation considering thermal
Deformation (m)
Figure 8 The bore deformation
The cylinder liner typically shows a deformation alongcylinder length axis and along cylinder circumference dueto bolting prestress and thermal load in the real conditionIn this study the deformation of bore in different caseshas been given by Figure 8 The mechanism of piston ringsealing is equivalent to a labyrinth seal where the gapclearances are determined by the position of the rings inthe groove considering the global movement and tilting ofthe piston [17] The Reynolds equations are solved iterativelyin each time step to determine the hydrodynamic pressuredistribution between ring running surface and liner All
6 Advances in Mechanical Engineering
0 90 180 270 360 450 540 630 720minus010
minus008
minus006
minus004
minus002
000
002
004
CA (deg)
Tilti
ng an
gle o
f pist
on (d
eg)
Figure 9 The tilting angle of piston during operation
minus008
minus006
minus004
minus002
000
002
004
006
008
First ring Second ring Oil ring
Crank angle (deg)0minus360 360
The p
ositi
on o
f rin
gs in
gro
ove (
mm
)
Figure 10 The position of rings in groove
relevant mechanisms are considered the calculation is donequasi-statically per time step The tilting angle of piston isgiven by Figure 9 And the motion of each ring in grooveduring operation is shown in Figure 10 and the thickness offilm oil between each ring face and bore is shown in Figure 11
32 Temperature Distribution Using the mathematicalmodel developed above the HTCs distribution in pistongrooveslands can be determined after getting the positionof each ring and the film thickness between each ring andbore Based on the determined HTCs in the top head pistonlandsgrooves and piston skirt the temperature distributionof the piston is predicted by FEA in ANSYS (Figures 12 and13) As shown in Figures 12 and 13 the temperature intensitydistribution decreases gradually from the head of the pistonto the bottom of the skirt A maximum temperature ofapproximately 392∘C is obtained on the head of the pistonat the combustion chamber chamfer edge (Figure 12) This
0 60 120 180 240 300 360 420 480 540 600 660 7200000
0005
0010
0015
0020
0025
Crank angle (deg)
Film
thic
knes
s (m
m)
First ringSecond ringOil ring
Figure 11 The film thickness of each ring
400350300250200
392∘CΔT
MX195∘C
156∘C134∘C
11689
4
147505
178116
208728
239339
269951
300562
331173
361785
392396
Figure 12 The temperature distribution of piston head
result is similar to that obtained on a similar type of pistonin an earlier study [19] The temperature decreases radicallytowards the outside and inside of piston The temperature is156∘C and 134∘C at the bottom of fire land and second landrespectively As it is shown in Figure 11 the temperaturedistribution in the skirt bolt and pin are lower than thepiston The maximum temperature is 1556∘C 250∘C and997∘C respectively
33TheMechanical Loads Theworking pistonnot only bearsa thermal load but also the high pressure of the fuel gasand the inertia force created by the reciprocating motionThe most strenuous condition of running the piston is themoment when the pressure in the combustion chamberreaches its maximum valueTherefore this study lays empha-sis on the stable stress at the combustion moment whenoperating at a stable speed
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
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- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
Research ArticleThermomechanical Fatigue Life Prediction for a Marine DieselEngine Piston considering Ring Dynamics
Tao He12 Xiqun Lu1 Dequan Zou12 Yibin Guo1 Wanyou Li1 and Minli Huang3
1 College of Power and Energy Engineering Harbin Engineering University Harbin Heilongjiang 150001 China2Washington University in St Louis St Louis MO 63108 USA3 Parks College of Engineering Aviation and Technology Saint Louis University St Louis MO 63105 USA
Correspondence should be addressed to Xiqun Lu luxiqunhrbeueducn
Received 11 April 2014 Accepted 17 July 2014 Published 19 October 2014
Academic Editor Mustafa Canakci
Copyright copy 2014 Tao He et al This is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
A newly designed marine diesel engine piston was modeled using a precise finite element analysis (FEA) The high cycle fatigue(HCF) safety factor prediction procedure designed in this study incorporated lubrication thermal and structure analysisThepistonring dynamics calculation determined the predicted thickness of lubrication oil film The film thickness influenced the calculatedmagnitude of the heat transfer coefficient (HTC) used in the thermal loads analysis Moreover the gas pressure of ring lands andring grooves used in mechanical analysis is predicted based on the piston ring dynamics model
1 Introduction
The increasing demand for high power density low emissionand low fuel consumption engines impose many restrictionson the design of diesel engine components The piston isone of the most challenging components in diesel enginedesign Pistons are subjected to high thermal andmechanicalloads Large temperature difference between piston crownsand cooling galleries induce significant thermal loads Inaddition gas pressure and piston acceleration can developcyclic mechanical stresses which are superimposed on earlierthermal stressed components This cycle of thermal andmechanical stresses causes the thermomechanical fatigue thatis the main cause of failure in diesel engine pistons
In this study the authors focus on damage causedby fatigue This damage is created both by thermal andmechanical stresses [1] To improve the life and reliabilityof pistons a large number of fatigue tests are carried outwhen designing new pistons [2ndash4] However to reduce thecost and time involved in fatigue testing many engine man-ufactures use FEA to predict the distribution of temperatureand stress on engine components The fast development ofthe numerical calculating technology has allowed FEA tobecome a significant tool in mechanical dynamics analysis
thermal analysis and thermomechanical coupling analysis ofnew piston designs [5ndash8] and in thermomechanical fatigueanalysis [9] Under thermomechanical fatigue loading pistonfailure may occur due to fatigue material degradation due toenvironmental influence (oxidation) and creep mechanisms[10] Thermomechanical fatigue life assessment methods canbe classified as empirical methods fracture mechanics the-ories continuum mechanical models and models based onmicrostructure [11] Empirical models correlate the numberof cycles to failure to parameters of the hysteresis loop forexample stress strain and plastic strain [12]
In this study a three-dimensional FEA is used to predictthe thermomechanical behavior of a newly designed dieselmarine engine piston In order to accurately determine theheat transfer coefficient (HTC) of the piston head the oilfilm is taken into consideration in the thermal analysis Thethicknesses of oil film between ringpiston and ringbore aredetermined using a ring pack lubrication model To calculatethe oil pressure distribution in the piston landsgroovesoperation a piston ring dynamics model is used in themechanical loads analysis The coupled actions of thermalloads and mechanical loads (including combustion pressureinertial load and oil pressure in ring landsgrooves) are usedto predict fatigue life The prediction procedure designed
Hindawi Publishing CorporationAdvances in Mechanical EngineeringVolume 2014 Article ID 429637 10 pageshttpdxdoiorg1011552014429637
2 Advances in Mechanical Engineering
Connecting bolt
Piston headSkirtPin
RodConnecting rodsmall end bush
(a) Solid model of piston (b) FE model of piston
Figure 1 The solid and FE model of the piston
Table 1 Engine parameters and piston materials
Design structure CompositeDiameter of bore (mm) 270Max combustion pressure (MPa) 23Rated power (KW) 455Rated speed (rpm) 1000Stroke (mm) 330Material of head 42CrMoAMaterial of skirt QT700-2Material of bolt 18Cr2Ni4WAMaterial of pin 12CrNi4A
in this study is the combination of lubrication analysis andstructure analysis The results obtained by this new methodwill provide a guideline for further optimizing piston design
2 The Finite Element Model
Due to the symmetrical structure of the piston a 14 3Dsolid model (Figure 1(a)) including piston pin and rodwas created The FE software ANSYS was used for FEAin this study For the FE model 3D 8-node solid elementssolid45 was chosen to perform the thermomechanical cou-pled analysis As shown in Figure 1(b) 37246nodes and 60638elements were obtained The materials of each part are listedin Table 1 Since this study focuses on the piston propertiesthe connection rod is set as a rigid body for analysis
The surface-surface contact unit is placed on the contactsurface between the piston pin hole and the piston pin headand skirt head and bolt skirt and bolt pin and bush pin andskirt and bush and rod Figure 2 shows the contact pairs inthis piston model
Bush-rod
Pin-bush
Pin-skirt
Skirt-bolt
Head-skirt
Head-bolt
Figure 2 The contact pairs distribution in the piston model
3 Theory
31 Thermal Boundary Conditions Piston temperature isusually considered to be independent of the operating statesand remains constant during a working cycle [13] Sincethe time response of piston material to the variation ofboundary conditions in a firing cycle is very slow a steadystate thermal analysis has been done considering the typicalvalues of temperatures and heat transfer coefficients at pistonboundary surfaces during one firing cycle Based on thethird kind of steady-state heat conduction conductive heattransfer boundary condition is that the temperature of thefluid medium contacting to the objects and the heat transfercoefficient are known and can be shown as
119896120597119879
120597119899
10038161003816100381610038161003816100381610038161003816119910= 120572 (119879 minus 119879119891)
10038161003816100381610038161003816119910 (1)
Advances in Mechanical Engineering 3
1600
1400
1200
1000
800
600
400
200
0 60 120 180 240 300 360 420 480 540 600 660 720
CA (deg)
6000
5000
4000
3000
2000
1000
00 100 200 300 400 500 600 700
CA (deg)
Tg
(K)
hg
(W(
m2
K))
Figure 3 ℎ119892 119879119892calculated by GT-Power
where 119879119891 is the medium temperature 120572 is the HTC and 119879119891can be constant or time and position variety as well as 120572 [14]
(1) HTC on Piston Top Surface Based on the assumption of asteady working state of the engine the average HTC and theaverage piston surface temperature in a whole working cyclecan be given as
ℎ119898 =1
720int
720
0
ℎ119892119889120593
119879res =1
720 sdot ℎ119898
int
720
0
ℎ119892119879119892119889120593
(2)
where ℎ119892 119879119892 are the instant HTC of gas at piston surface andinstant gas temperature According to the design parametersof the engine ℎ119892 and 119879119892 can be calculated by GT-Power(Figure 3) According to (2) ℎ119898 = 121488Wm2 K and119879res = 91331K
Using Sealrsquos formula and experimental data the HTC ofpiston head is the function of position in radial direction
If 119903 lt 119873 ℎ119903 =2ℎ119898
1 + 11989001119873151198900111990315
If 119903 ge 119873 ℎ119903 =2ℎ119898
1 + 119890011198731511989001(2119873minus119903)
15
(3)
where 119903 is the distance from a local point to the center axis ofthe piston head and 119873 is the distance from the point wherethe maximum temperature occurs to the center axis of thepiston For FEA modeling the top surface of the pistonis divided into 10 subregions radially Then based on thepistonrsquos structural parameters the HTC on the top of headcan be determined by (3) The HTC distribution of the tophead of the newly designed piston is shown in Figure 4
(2) HTC at Skirt and Cooling Oil Channels The currentanalysis used HTC values at the skirt and oil channels thatwere determined by Lu et al [14]Their analysis used a pistonwith a similar structure and size
00000 00267 00534 00801 01068 013350
500
1000
1500
2000H
eat t
rans
fer c
oeffi
cien
t(W
m2
K)
Figure 4 HTCs distribution at the top of piston head
(3) HTCs at Piston Ring LandsGrooveThe thermal transferprocess in piston ring landsgrooves is shown in Figure 5Figure 5(a) is the thermal resistance map from piston to borethrough ring land and Figure 5(b) is the thermal resistancemap from piston to bore through ring grooveThe resistancesin the transfer paths (Figure 5) have been specific by Luet al [15] Parameters such as the position of ring duringoperation and the thickness of oil film between ringboreand ringpiston are important in the heat transfer process Inorder to predict the magnitude of those parameters a ringdynamics analysis is applied in this study
(4) Ring Dynamics The motion of piston ring withinthe piston groove can be described by the axial rotational(torsional twist) and radial motions in the three respectivedegrees of freedom The ring motion in the circumferencedirection is neglected in this study A small section ofthe ring at a circumferential location is considered in theanalysis (Figure 6) The whole ring dynamic analysis modeldeveloped by Tian et al [16] is used in this study Consideringthe complexity of heat transfer and time consumption of
4 Advances in Mechanical Engineering
Ring
Piston
Bore
Piston landPiston groove
R1 R2 R3
Air between pistonland and bore
Film thicknesson the bore
Tpiston Twater
Oil film
Thickness of bore
(a) Resistance map of heat transfer in piston land
R4 R5 R6 R7
RingFilm thicknessof ringbore
Air between pistonland and bore
Tpiston TwaterThickness of bore
(b) Resistance map of heat transfer in piston groove
Figure 5 The resistance map of heat transfer from piston head to bore
r
y
120572
Ftension
Piston
Ring
Liner
Fgpre
Fgoil
Mgoil
Flpre
Mlpre
Fcfrc
Mcfrc
Mgasp
Fcasp
Flpre
hcg
Mgfrc Fgfrc
Pi
FcoilMcoil
Fgasp
Pi+1
cg (ycg)
Oil film
Figure 6 Free body diagram of ring cross section
simulation the section of thrust side (TS) is used Thegoverning equations for the ring motion are
119898119903
1198892119910cg
1198891199052= 119865119892oil + 119865119892asp + 119865119888frc minus 119865119897pre minus 119898119903119892
1198681199031198892120572
1198891199052= 119872119892oil +119872119892asp +119872119888frc +119872119897pre +119872119888oil
+119872119888asp minus 119870119903119905120572
119898119903
1198892ℎcg
1198891199052= 119865119892pre + 119865119892frc + 119865119888oil minus 119865119888asp
minus 1198651015840
119897pre + 119870119903119903 (ℎ1015840+ ℎ0)
(4)
where 119910cg and ℎcg are the axial and radial position of thecenter of gravity of the ring and120572 is the twist angle119898119903 119868119903 and119870119903119905 are ringmassmoment of inertia for toroidal rotation andcross-sectional torsional stiffness 119870119903119903 is the radial tensionstiffness ℎ1015840 is the reduction in ring radius at installation andℎ0 is the minimum ring-bore oil film thickness (119865tension =
119870119903119903(ℎ1015840+ ℎ0)) 119865 and119872 are the forces and moments acting on
the ring cross section (Figure 6) In (4) the first subscript forthe force and moment terms indicates location on the ring(119892 = groove 119888 = cylinder and 119897 = land) and the secondsubscript describes the source of the force or moment (oil =oil pressure asp = normal pressure due to asperity contactpre = gas pressure and frc = hydrodynamic or boundaryfriction) The torsional moment119872119903119905 is calculated as
119872119903119905 = 119870119903119905120572 (5)
For a complete ring with rectangular cross section the cross-sectional torsional stiffness (119870119903119905) is given by
119870119903119905 =1198641198873 ln (119863119889)3 (119863 + 119889)
(6)
where 119864 is the modulus of elasticity of piston ring 119887 is theaxial height of piston ring section 119889 is the inner diameterand 119863 is the outer diameter of piston ring The axial motionof a ring relative to piston can be expressed as
119910cg = 119910119901 + 119910119903119901
119889119910cg
119889119905=119889119910119901
119889119905+119889119910119903119901
119889119905
1198892119910cg
1198891199052=1198892119910119901
1198891199052+1198892119910119903119901
1198891199052
(7)
where 119910119901 is the axial position of the piston and 119910119903119901 is the axialposition of the ring related to the piston And 119910119901 can be given
Advances in Mechanical Engineering 5
52
Ges
chliff
en08 08
R04
R 04
3middot middot middot12 120583m3middot middot middot12120583m
45 ∘
30 ∘radicRz4
44middot middot middot66120583mradicRz 6Ground
R 03 max
R03
max
minus0005minus0050
First ring Second ringand third ring
Oil ring
04
max
04
max
35plusmn02
09 plusmn01
05plusmn005
145plusmn045
145plusmn045
02plusmn01
02plusmn01
45∘ plusmn5∘
45∘ plusmn5∘
35 ∘plusmn2 ∘
35∘ plusmn2∘
asymp35
3∘ plusmn 30998400
Figure 7 The geometry of the piston rings
out by the piston secondary motion together with the axialmotion Using a developed version of an existing ring packlubrication model Gamble et al [17] investigated the effectof piston secondary motion on the performance of a dieselengine piston ring pack in terms of gas flow and interringgas pressures For an example engine operating condition theeffect of secondarymotion on the ring packwas calculated fora number of ring gap positional combinationsThe secondarymotion and the positions of the ring gaps were shown to havean effect on the ring pack operating conditions such as oilfilm thickness friction wear oil transport and degradationAnd in order to determine the parameter 119910119901 the tilt of pistonand axial position are needed and those two parameters canbe calculated by iteration algorithm used in [17]
Forces and moment associated with land and groove gaspressure are calculated using pressure solutions from the gasdynamics submodel Forces and moments associated withoil pressure are obtained from the lubrication submodeland those associated with local asperity contact pressure arecalculated by asperity deformationmodel Ring axial positionand twist influence gas flow paths and the forces at the ring-groove interface Ring twist also affects the effective profilepresented by the ring face to the cylinder bore and thus affectsoil film thickness and ring friction The lubrication modelasperity deformation model and oil film squeezing model atring side and groove interface have been previously described[16 18]
The structure of the rings used in the piston is shownin Figure 7 Each ring is modeled as a single mass twisting(including pretwist angles) is considered The equations ofmotion which considers equilibrium condition of momentsand forces for each ring are solvedThe dynamic componentsof ringmotion are calculated using time integrationmethods
07
06
05
04
03
02
01
0
Hei
ght o
f bor
e (m
)
minus500E minus 05 500E minus 05 150E minus 04 250E minus 04
Deformation considering install prestressDeformation considering both of install prestress and thermalDeformation considering thermal
Deformation (m)
Figure 8 The bore deformation
The cylinder liner typically shows a deformation alongcylinder length axis and along cylinder circumference dueto bolting prestress and thermal load in the real conditionIn this study the deformation of bore in different caseshas been given by Figure 8 The mechanism of piston ringsealing is equivalent to a labyrinth seal where the gapclearances are determined by the position of the rings inthe groove considering the global movement and tilting ofthe piston [17] The Reynolds equations are solved iterativelyin each time step to determine the hydrodynamic pressuredistribution between ring running surface and liner All
6 Advances in Mechanical Engineering
0 90 180 270 360 450 540 630 720minus010
minus008
minus006
minus004
minus002
000
002
004
CA (deg)
Tilti
ng an
gle o
f pist
on (d
eg)
Figure 9 The tilting angle of piston during operation
minus008
minus006
minus004
minus002
000
002
004
006
008
First ring Second ring Oil ring
Crank angle (deg)0minus360 360
The p
ositi
on o
f rin
gs in
gro
ove (
mm
)
Figure 10 The position of rings in groove
relevant mechanisms are considered the calculation is donequasi-statically per time step The tilting angle of piston isgiven by Figure 9 And the motion of each ring in grooveduring operation is shown in Figure 10 and the thickness offilm oil between each ring face and bore is shown in Figure 11
32 Temperature Distribution Using the mathematicalmodel developed above the HTCs distribution in pistongrooveslands can be determined after getting the positionof each ring and the film thickness between each ring andbore Based on the determined HTCs in the top head pistonlandsgrooves and piston skirt the temperature distributionof the piston is predicted by FEA in ANSYS (Figures 12 and13) As shown in Figures 12 and 13 the temperature intensitydistribution decreases gradually from the head of the pistonto the bottom of the skirt A maximum temperature ofapproximately 392∘C is obtained on the head of the pistonat the combustion chamber chamfer edge (Figure 12) This
0 60 120 180 240 300 360 420 480 540 600 660 7200000
0005
0010
0015
0020
0025
Crank angle (deg)
Film
thic
knes
s (m
m)
First ringSecond ringOil ring
Figure 11 The film thickness of each ring
400350300250200
392∘CΔT
MX195∘C
156∘C134∘C
11689
4
147505
178116
208728
239339
269951
300562
331173
361785
392396
Figure 12 The temperature distribution of piston head
result is similar to that obtained on a similar type of pistonin an earlier study [19] The temperature decreases radicallytowards the outside and inside of piston The temperature is156∘C and 134∘C at the bottom of fire land and second landrespectively As it is shown in Figure 11 the temperaturedistribution in the skirt bolt and pin are lower than thepiston The maximum temperature is 1556∘C 250∘C and997∘C respectively
33TheMechanical Loads Theworking pistonnot only bearsa thermal load but also the high pressure of the fuel gasand the inertia force created by the reciprocating motionThe most strenuous condition of running the piston is themoment when the pressure in the combustion chamberreaches its maximum valueTherefore this study lays empha-sis on the stable stress at the combustion moment whenoperating at a stable speed
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Shock and Vibration
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Mechanical Engineering
Advances in
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Civil EngineeringAdvances in
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Electrical and Computer Engineering
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Distributed Sensor Networks
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RoboticsJournal of
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- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
2 Advances in Mechanical Engineering
Connecting bolt
Piston headSkirtPin
RodConnecting rodsmall end bush
(a) Solid model of piston (b) FE model of piston
Figure 1 The solid and FE model of the piston
Table 1 Engine parameters and piston materials
Design structure CompositeDiameter of bore (mm) 270Max combustion pressure (MPa) 23Rated power (KW) 455Rated speed (rpm) 1000Stroke (mm) 330Material of head 42CrMoAMaterial of skirt QT700-2Material of bolt 18Cr2Ni4WAMaterial of pin 12CrNi4A
in this study is the combination of lubrication analysis andstructure analysis The results obtained by this new methodwill provide a guideline for further optimizing piston design
2 The Finite Element Model
Due to the symmetrical structure of the piston a 14 3Dsolid model (Figure 1(a)) including piston pin and rodwas created The FE software ANSYS was used for FEAin this study For the FE model 3D 8-node solid elementssolid45 was chosen to perform the thermomechanical cou-pled analysis As shown in Figure 1(b) 37246nodes and 60638elements were obtained The materials of each part are listedin Table 1 Since this study focuses on the piston propertiesthe connection rod is set as a rigid body for analysis
The surface-surface contact unit is placed on the contactsurface between the piston pin hole and the piston pin headand skirt head and bolt skirt and bolt pin and bush pin andskirt and bush and rod Figure 2 shows the contact pairs inthis piston model
Bush-rod
Pin-bush
Pin-skirt
Skirt-bolt
Head-skirt
Head-bolt
Figure 2 The contact pairs distribution in the piston model
3 Theory
31 Thermal Boundary Conditions Piston temperature isusually considered to be independent of the operating statesand remains constant during a working cycle [13] Sincethe time response of piston material to the variation ofboundary conditions in a firing cycle is very slow a steadystate thermal analysis has been done considering the typicalvalues of temperatures and heat transfer coefficients at pistonboundary surfaces during one firing cycle Based on thethird kind of steady-state heat conduction conductive heattransfer boundary condition is that the temperature of thefluid medium contacting to the objects and the heat transfercoefficient are known and can be shown as
119896120597119879
120597119899
10038161003816100381610038161003816100381610038161003816119910= 120572 (119879 minus 119879119891)
10038161003816100381610038161003816119910 (1)
Advances in Mechanical Engineering 3
1600
1400
1200
1000
800
600
400
200
0 60 120 180 240 300 360 420 480 540 600 660 720
CA (deg)
6000
5000
4000
3000
2000
1000
00 100 200 300 400 500 600 700
CA (deg)
Tg
(K)
hg
(W(
m2
K))
Figure 3 ℎ119892 119879119892calculated by GT-Power
where 119879119891 is the medium temperature 120572 is the HTC and 119879119891can be constant or time and position variety as well as 120572 [14]
(1) HTC on Piston Top Surface Based on the assumption of asteady working state of the engine the average HTC and theaverage piston surface temperature in a whole working cyclecan be given as
ℎ119898 =1
720int
720
0
ℎ119892119889120593
119879res =1
720 sdot ℎ119898
int
720
0
ℎ119892119879119892119889120593
(2)
where ℎ119892 119879119892 are the instant HTC of gas at piston surface andinstant gas temperature According to the design parametersof the engine ℎ119892 and 119879119892 can be calculated by GT-Power(Figure 3) According to (2) ℎ119898 = 121488Wm2 K and119879res = 91331K
Using Sealrsquos formula and experimental data the HTC ofpiston head is the function of position in radial direction
If 119903 lt 119873 ℎ119903 =2ℎ119898
1 + 11989001119873151198900111990315
If 119903 ge 119873 ℎ119903 =2ℎ119898
1 + 119890011198731511989001(2119873minus119903)
15
(3)
where 119903 is the distance from a local point to the center axis ofthe piston head and 119873 is the distance from the point wherethe maximum temperature occurs to the center axis of thepiston For FEA modeling the top surface of the pistonis divided into 10 subregions radially Then based on thepistonrsquos structural parameters the HTC on the top of headcan be determined by (3) The HTC distribution of the tophead of the newly designed piston is shown in Figure 4
(2) HTC at Skirt and Cooling Oil Channels The currentanalysis used HTC values at the skirt and oil channels thatwere determined by Lu et al [14]Their analysis used a pistonwith a similar structure and size
00000 00267 00534 00801 01068 013350
500
1000
1500
2000H
eat t
rans
fer c
oeffi
cien
t(W
m2
K)
Figure 4 HTCs distribution at the top of piston head
(3) HTCs at Piston Ring LandsGrooveThe thermal transferprocess in piston ring landsgrooves is shown in Figure 5Figure 5(a) is the thermal resistance map from piston to borethrough ring land and Figure 5(b) is the thermal resistancemap from piston to bore through ring grooveThe resistancesin the transfer paths (Figure 5) have been specific by Luet al [15] Parameters such as the position of ring duringoperation and the thickness of oil film between ringboreand ringpiston are important in the heat transfer process Inorder to predict the magnitude of those parameters a ringdynamics analysis is applied in this study
(4) Ring Dynamics The motion of piston ring withinthe piston groove can be described by the axial rotational(torsional twist) and radial motions in the three respectivedegrees of freedom The ring motion in the circumferencedirection is neglected in this study A small section ofthe ring at a circumferential location is considered in theanalysis (Figure 6) The whole ring dynamic analysis modeldeveloped by Tian et al [16] is used in this study Consideringthe complexity of heat transfer and time consumption of
4 Advances in Mechanical Engineering
Ring
Piston
Bore
Piston landPiston groove
R1 R2 R3
Air between pistonland and bore
Film thicknesson the bore
Tpiston Twater
Oil film
Thickness of bore
(a) Resistance map of heat transfer in piston land
R4 R5 R6 R7
RingFilm thicknessof ringbore
Air between pistonland and bore
Tpiston TwaterThickness of bore
(b) Resistance map of heat transfer in piston groove
Figure 5 The resistance map of heat transfer from piston head to bore
r
y
120572
Ftension
Piston
Ring
Liner
Fgpre
Fgoil
Mgoil
Flpre
Mlpre
Fcfrc
Mcfrc
Mgasp
Fcasp
Flpre
hcg
Mgfrc Fgfrc
Pi
FcoilMcoil
Fgasp
Pi+1
cg (ycg)
Oil film
Figure 6 Free body diagram of ring cross section
simulation the section of thrust side (TS) is used Thegoverning equations for the ring motion are
119898119903
1198892119910cg
1198891199052= 119865119892oil + 119865119892asp + 119865119888frc minus 119865119897pre minus 119898119903119892
1198681199031198892120572
1198891199052= 119872119892oil +119872119892asp +119872119888frc +119872119897pre +119872119888oil
+119872119888asp minus 119870119903119905120572
119898119903
1198892ℎcg
1198891199052= 119865119892pre + 119865119892frc + 119865119888oil minus 119865119888asp
minus 1198651015840
119897pre + 119870119903119903 (ℎ1015840+ ℎ0)
(4)
where 119910cg and ℎcg are the axial and radial position of thecenter of gravity of the ring and120572 is the twist angle119898119903 119868119903 and119870119903119905 are ringmassmoment of inertia for toroidal rotation andcross-sectional torsional stiffness 119870119903119903 is the radial tensionstiffness ℎ1015840 is the reduction in ring radius at installation andℎ0 is the minimum ring-bore oil film thickness (119865tension =
119870119903119903(ℎ1015840+ ℎ0)) 119865 and119872 are the forces and moments acting on
the ring cross section (Figure 6) In (4) the first subscript forthe force and moment terms indicates location on the ring(119892 = groove 119888 = cylinder and 119897 = land) and the secondsubscript describes the source of the force or moment (oil =oil pressure asp = normal pressure due to asperity contactpre = gas pressure and frc = hydrodynamic or boundaryfriction) The torsional moment119872119903119905 is calculated as
119872119903119905 = 119870119903119905120572 (5)
For a complete ring with rectangular cross section the cross-sectional torsional stiffness (119870119903119905) is given by
119870119903119905 =1198641198873 ln (119863119889)3 (119863 + 119889)
(6)
where 119864 is the modulus of elasticity of piston ring 119887 is theaxial height of piston ring section 119889 is the inner diameterand 119863 is the outer diameter of piston ring The axial motionof a ring relative to piston can be expressed as
119910cg = 119910119901 + 119910119903119901
119889119910cg
119889119905=119889119910119901
119889119905+119889119910119903119901
119889119905
1198892119910cg
1198891199052=1198892119910119901
1198891199052+1198892119910119903119901
1198891199052
(7)
where 119910119901 is the axial position of the piston and 119910119903119901 is the axialposition of the ring related to the piston And 119910119901 can be given
Advances in Mechanical Engineering 5
52
Ges
chliff
en08 08
R04
R 04
3middot middot middot12 120583m3middot middot middot12120583m
45 ∘
30 ∘radicRz4
44middot middot middot66120583mradicRz 6Ground
R 03 max
R03
max
minus0005minus0050
First ring Second ringand third ring
Oil ring
04
max
04
max
35plusmn02
09 plusmn01
05plusmn005
145plusmn045
145plusmn045
02plusmn01
02plusmn01
45∘ plusmn5∘
45∘ plusmn5∘
35 ∘plusmn2 ∘
35∘ plusmn2∘
asymp35
3∘ plusmn 30998400
Figure 7 The geometry of the piston rings
out by the piston secondary motion together with the axialmotion Using a developed version of an existing ring packlubrication model Gamble et al [17] investigated the effectof piston secondary motion on the performance of a dieselengine piston ring pack in terms of gas flow and interringgas pressures For an example engine operating condition theeffect of secondarymotion on the ring packwas calculated fora number of ring gap positional combinationsThe secondarymotion and the positions of the ring gaps were shown to havean effect on the ring pack operating conditions such as oilfilm thickness friction wear oil transport and degradationAnd in order to determine the parameter 119910119901 the tilt of pistonand axial position are needed and those two parameters canbe calculated by iteration algorithm used in [17]
Forces and moment associated with land and groove gaspressure are calculated using pressure solutions from the gasdynamics submodel Forces and moments associated withoil pressure are obtained from the lubrication submodeland those associated with local asperity contact pressure arecalculated by asperity deformationmodel Ring axial positionand twist influence gas flow paths and the forces at the ring-groove interface Ring twist also affects the effective profilepresented by the ring face to the cylinder bore and thus affectsoil film thickness and ring friction The lubrication modelasperity deformation model and oil film squeezing model atring side and groove interface have been previously described[16 18]
The structure of the rings used in the piston is shownin Figure 7 Each ring is modeled as a single mass twisting(including pretwist angles) is considered The equations ofmotion which considers equilibrium condition of momentsand forces for each ring are solvedThe dynamic componentsof ringmotion are calculated using time integrationmethods
07
06
05
04
03
02
01
0
Hei
ght o
f bor
e (m
)
minus500E minus 05 500E minus 05 150E minus 04 250E minus 04
Deformation considering install prestressDeformation considering both of install prestress and thermalDeformation considering thermal
Deformation (m)
Figure 8 The bore deformation
The cylinder liner typically shows a deformation alongcylinder length axis and along cylinder circumference dueto bolting prestress and thermal load in the real conditionIn this study the deformation of bore in different caseshas been given by Figure 8 The mechanism of piston ringsealing is equivalent to a labyrinth seal where the gapclearances are determined by the position of the rings inthe groove considering the global movement and tilting ofthe piston [17] The Reynolds equations are solved iterativelyin each time step to determine the hydrodynamic pressuredistribution between ring running surface and liner All
6 Advances in Mechanical Engineering
0 90 180 270 360 450 540 630 720minus010
minus008
minus006
minus004
minus002
000
002
004
CA (deg)
Tilti
ng an
gle o
f pist
on (d
eg)
Figure 9 The tilting angle of piston during operation
minus008
minus006
minus004
minus002
000
002
004
006
008
First ring Second ring Oil ring
Crank angle (deg)0minus360 360
The p
ositi
on o
f rin
gs in
gro
ove (
mm
)
Figure 10 The position of rings in groove
relevant mechanisms are considered the calculation is donequasi-statically per time step The tilting angle of piston isgiven by Figure 9 And the motion of each ring in grooveduring operation is shown in Figure 10 and the thickness offilm oil between each ring face and bore is shown in Figure 11
32 Temperature Distribution Using the mathematicalmodel developed above the HTCs distribution in pistongrooveslands can be determined after getting the positionof each ring and the film thickness between each ring andbore Based on the determined HTCs in the top head pistonlandsgrooves and piston skirt the temperature distributionof the piston is predicted by FEA in ANSYS (Figures 12 and13) As shown in Figures 12 and 13 the temperature intensitydistribution decreases gradually from the head of the pistonto the bottom of the skirt A maximum temperature ofapproximately 392∘C is obtained on the head of the pistonat the combustion chamber chamfer edge (Figure 12) This
0 60 120 180 240 300 360 420 480 540 600 660 7200000
0005
0010
0015
0020
0025
Crank angle (deg)
Film
thic
knes
s (m
m)
First ringSecond ringOil ring
Figure 11 The film thickness of each ring
400350300250200
392∘CΔT
MX195∘C
156∘C134∘C
11689
4
147505
178116
208728
239339
269951
300562
331173
361785
392396
Figure 12 The temperature distribution of piston head
result is similar to that obtained on a similar type of pistonin an earlier study [19] The temperature decreases radicallytowards the outside and inside of piston The temperature is156∘C and 134∘C at the bottom of fire land and second landrespectively As it is shown in Figure 11 the temperaturedistribution in the skirt bolt and pin are lower than thepiston The maximum temperature is 1556∘C 250∘C and997∘C respectively
33TheMechanical Loads Theworking pistonnot only bearsa thermal load but also the high pressure of the fuel gasand the inertia force created by the reciprocating motionThe most strenuous condition of running the piston is themoment when the pressure in the combustion chamberreaches its maximum valueTherefore this study lays empha-sis on the stable stress at the combustion moment whenoperating at a stable speed
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Antennas andPropagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
Advances in Mechanical Engineering 3
1600
1400
1200
1000
800
600
400
200
0 60 120 180 240 300 360 420 480 540 600 660 720
CA (deg)
6000
5000
4000
3000
2000
1000
00 100 200 300 400 500 600 700
CA (deg)
Tg
(K)
hg
(W(
m2
K))
Figure 3 ℎ119892 119879119892calculated by GT-Power
where 119879119891 is the medium temperature 120572 is the HTC and 119879119891can be constant or time and position variety as well as 120572 [14]
(1) HTC on Piston Top Surface Based on the assumption of asteady working state of the engine the average HTC and theaverage piston surface temperature in a whole working cyclecan be given as
ℎ119898 =1
720int
720
0
ℎ119892119889120593
119879res =1
720 sdot ℎ119898
int
720
0
ℎ119892119879119892119889120593
(2)
where ℎ119892 119879119892 are the instant HTC of gas at piston surface andinstant gas temperature According to the design parametersof the engine ℎ119892 and 119879119892 can be calculated by GT-Power(Figure 3) According to (2) ℎ119898 = 121488Wm2 K and119879res = 91331K
Using Sealrsquos formula and experimental data the HTC ofpiston head is the function of position in radial direction
If 119903 lt 119873 ℎ119903 =2ℎ119898
1 + 11989001119873151198900111990315
If 119903 ge 119873 ℎ119903 =2ℎ119898
1 + 119890011198731511989001(2119873minus119903)
15
(3)
where 119903 is the distance from a local point to the center axis ofthe piston head and 119873 is the distance from the point wherethe maximum temperature occurs to the center axis of thepiston For FEA modeling the top surface of the pistonis divided into 10 subregions radially Then based on thepistonrsquos structural parameters the HTC on the top of headcan be determined by (3) The HTC distribution of the tophead of the newly designed piston is shown in Figure 4
(2) HTC at Skirt and Cooling Oil Channels The currentanalysis used HTC values at the skirt and oil channels thatwere determined by Lu et al [14]Their analysis used a pistonwith a similar structure and size
00000 00267 00534 00801 01068 013350
500
1000
1500
2000H
eat t
rans
fer c
oeffi
cien
t(W
m2
K)
Figure 4 HTCs distribution at the top of piston head
(3) HTCs at Piston Ring LandsGrooveThe thermal transferprocess in piston ring landsgrooves is shown in Figure 5Figure 5(a) is the thermal resistance map from piston to borethrough ring land and Figure 5(b) is the thermal resistancemap from piston to bore through ring grooveThe resistancesin the transfer paths (Figure 5) have been specific by Luet al [15] Parameters such as the position of ring duringoperation and the thickness of oil film between ringboreand ringpiston are important in the heat transfer process Inorder to predict the magnitude of those parameters a ringdynamics analysis is applied in this study
(4) Ring Dynamics The motion of piston ring withinthe piston groove can be described by the axial rotational(torsional twist) and radial motions in the three respectivedegrees of freedom The ring motion in the circumferencedirection is neglected in this study A small section ofthe ring at a circumferential location is considered in theanalysis (Figure 6) The whole ring dynamic analysis modeldeveloped by Tian et al [16] is used in this study Consideringthe complexity of heat transfer and time consumption of
4 Advances in Mechanical Engineering
Ring
Piston
Bore
Piston landPiston groove
R1 R2 R3
Air between pistonland and bore
Film thicknesson the bore
Tpiston Twater
Oil film
Thickness of bore
(a) Resistance map of heat transfer in piston land
R4 R5 R6 R7
RingFilm thicknessof ringbore
Air between pistonland and bore
Tpiston TwaterThickness of bore
(b) Resistance map of heat transfer in piston groove
Figure 5 The resistance map of heat transfer from piston head to bore
r
y
120572
Ftension
Piston
Ring
Liner
Fgpre
Fgoil
Mgoil
Flpre
Mlpre
Fcfrc
Mcfrc
Mgasp
Fcasp
Flpre
hcg
Mgfrc Fgfrc
Pi
FcoilMcoil
Fgasp
Pi+1
cg (ycg)
Oil film
Figure 6 Free body diagram of ring cross section
simulation the section of thrust side (TS) is used Thegoverning equations for the ring motion are
119898119903
1198892119910cg
1198891199052= 119865119892oil + 119865119892asp + 119865119888frc minus 119865119897pre minus 119898119903119892
1198681199031198892120572
1198891199052= 119872119892oil +119872119892asp +119872119888frc +119872119897pre +119872119888oil
+119872119888asp minus 119870119903119905120572
119898119903
1198892ℎcg
1198891199052= 119865119892pre + 119865119892frc + 119865119888oil minus 119865119888asp
minus 1198651015840
119897pre + 119870119903119903 (ℎ1015840+ ℎ0)
(4)
where 119910cg and ℎcg are the axial and radial position of thecenter of gravity of the ring and120572 is the twist angle119898119903 119868119903 and119870119903119905 are ringmassmoment of inertia for toroidal rotation andcross-sectional torsional stiffness 119870119903119903 is the radial tensionstiffness ℎ1015840 is the reduction in ring radius at installation andℎ0 is the minimum ring-bore oil film thickness (119865tension =
119870119903119903(ℎ1015840+ ℎ0)) 119865 and119872 are the forces and moments acting on
the ring cross section (Figure 6) In (4) the first subscript forthe force and moment terms indicates location on the ring(119892 = groove 119888 = cylinder and 119897 = land) and the secondsubscript describes the source of the force or moment (oil =oil pressure asp = normal pressure due to asperity contactpre = gas pressure and frc = hydrodynamic or boundaryfriction) The torsional moment119872119903119905 is calculated as
119872119903119905 = 119870119903119905120572 (5)
For a complete ring with rectangular cross section the cross-sectional torsional stiffness (119870119903119905) is given by
119870119903119905 =1198641198873 ln (119863119889)3 (119863 + 119889)
(6)
where 119864 is the modulus of elasticity of piston ring 119887 is theaxial height of piston ring section 119889 is the inner diameterand 119863 is the outer diameter of piston ring The axial motionof a ring relative to piston can be expressed as
119910cg = 119910119901 + 119910119903119901
119889119910cg
119889119905=119889119910119901
119889119905+119889119910119903119901
119889119905
1198892119910cg
1198891199052=1198892119910119901
1198891199052+1198892119910119903119901
1198891199052
(7)
where 119910119901 is the axial position of the piston and 119910119903119901 is the axialposition of the ring related to the piston And 119910119901 can be given
Advances in Mechanical Engineering 5
52
Ges
chliff
en08 08
R04
R 04
3middot middot middot12 120583m3middot middot middot12120583m
45 ∘
30 ∘radicRz4
44middot middot middot66120583mradicRz 6Ground
R 03 max
R03
max
minus0005minus0050
First ring Second ringand third ring
Oil ring
04
max
04
max
35plusmn02
09 plusmn01
05plusmn005
145plusmn045
145plusmn045
02plusmn01
02plusmn01
45∘ plusmn5∘
45∘ plusmn5∘
35 ∘plusmn2 ∘
35∘ plusmn2∘
asymp35
3∘ plusmn 30998400
Figure 7 The geometry of the piston rings
out by the piston secondary motion together with the axialmotion Using a developed version of an existing ring packlubrication model Gamble et al [17] investigated the effectof piston secondary motion on the performance of a dieselengine piston ring pack in terms of gas flow and interringgas pressures For an example engine operating condition theeffect of secondarymotion on the ring packwas calculated fora number of ring gap positional combinationsThe secondarymotion and the positions of the ring gaps were shown to havean effect on the ring pack operating conditions such as oilfilm thickness friction wear oil transport and degradationAnd in order to determine the parameter 119910119901 the tilt of pistonand axial position are needed and those two parameters canbe calculated by iteration algorithm used in [17]
Forces and moment associated with land and groove gaspressure are calculated using pressure solutions from the gasdynamics submodel Forces and moments associated withoil pressure are obtained from the lubrication submodeland those associated with local asperity contact pressure arecalculated by asperity deformationmodel Ring axial positionand twist influence gas flow paths and the forces at the ring-groove interface Ring twist also affects the effective profilepresented by the ring face to the cylinder bore and thus affectsoil film thickness and ring friction The lubrication modelasperity deformation model and oil film squeezing model atring side and groove interface have been previously described[16 18]
The structure of the rings used in the piston is shownin Figure 7 Each ring is modeled as a single mass twisting(including pretwist angles) is considered The equations ofmotion which considers equilibrium condition of momentsand forces for each ring are solvedThe dynamic componentsof ringmotion are calculated using time integrationmethods
07
06
05
04
03
02
01
0
Hei
ght o
f bor
e (m
)
minus500E minus 05 500E minus 05 150E minus 04 250E minus 04
Deformation considering install prestressDeformation considering both of install prestress and thermalDeformation considering thermal
Deformation (m)
Figure 8 The bore deformation
The cylinder liner typically shows a deformation alongcylinder length axis and along cylinder circumference dueto bolting prestress and thermal load in the real conditionIn this study the deformation of bore in different caseshas been given by Figure 8 The mechanism of piston ringsealing is equivalent to a labyrinth seal where the gapclearances are determined by the position of the rings inthe groove considering the global movement and tilting ofthe piston [17] The Reynolds equations are solved iterativelyin each time step to determine the hydrodynamic pressuredistribution between ring running surface and liner All
6 Advances in Mechanical Engineering
0 90 180 270 360 450 540 630 720minus010
minus008
minus006
minus004
minus002
000
002
004
CA (deg)
Tilti
ng an
gle o
f pist
on (d
eg)
Figure 9 The tilting angle of piston during operation
minus008
minus006
minus004
minus002
000
002
004
006
008
First ring Second ring Oil ring
Crank angle (deg)0minus360 360
The p
ositi
on o
f rin
gs in
gro
ove (
mm
)
Figure 10 The position of rings in groove
relevant mechanisms are considered the calculation is donequasi-statically per time step The tilting angle of piston isgiven by Figure 9 And the motion of each ring in grooveduring operation is shown in Figure 10 and the thickness offilm oil between each ring face and bore is shown in Figure 11
32 Temperature Distribution Using the mathematicalmodel developed above the HTCs distribution in pistongrooveslands can be determined after getting the positionof each ring and the film thickness between each ring andbore Based on the determined HTCs in the top head pistonlandsgrooves and piston skirt the temperature distributionof the piston is predicted by FEA in ANSYS (Figures 12 and13) As shown in Figures 12 and 13 the temperature intensitydistribution decreases gradually from the head of the pistonto the bottom of the skirt A maximum temperature ofapproximately 392∘C is obtained on the head of the pistonat the combustion chamber chamfer edge (Figure 12) This
0 60 120 180 240 300 360 420 480 540 600 660 7200000
0005
0010
0015
0020
0025
Crank angle (deg)
Film
thic
knes
s (m
m)
First ringSecond ringOil ring
Figure 11 The film thickness of each ring
400350300250200
392∘CΔT
MX195∘C
156∘C134∘C
11689
4
147505
178116
208728
239339
269951
300562
331173
361785
392396
Figure 12 The temperature distribution of piston head
result is similar to that obtained on a similar type of pistonin an earlier study [19] The temperature decreases radicallytowards the outside and inside of piston The temperature is156∘C and 134∘C at the bottom of fire land and second landrespectively As it is shown in Figure 11 the temperaturedistribution in the skirt bolt and pin are lower than thepiston The maximum temperature is 1556∘C 250∘C and997∘C respectively
33TheMechanical Loads Theworking pistonnot only bearsa thermal load but also the high pressure of the fuel gasand the inertia force created by the reciprocating motionThe most strenuous condition of running the piston is themoment when the pressure in the combustion chamberreaches its maximum valueTherefore this study lays empha-sis on the stable stress at the combustion moment whenoperating at a stable speed
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Antennas andPropagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
4 Advances in Mechanical Engineering
Ring
Piston
Bore
Piston landPiston groove
R1 R2 R3
Air between pistonland and bore
Film thicknesson the bore
Tpiston Twater
Oil film
Thickness of bore
(a) Resistance map of heat transfer in piston land
R4 R5 R6 R7
RingFilm thicknessof ringbore
Air between pistonland and bore
Tpiston TwaterThickness of bore
(b) Resistance map of heat transfer in piston groove
Figure 5 The resistance map of heat transfer from piston head to bore
r
y
120572
Ftension
Piston
Ring
Liner
Fgpre
Fgoil
Mgoil
Flpre
Mlpre
Fcfrc
Mcfrc
Mgasp
Fcasp
Flpre
hcg
Mgfrc Fgfrc
Pi
FcoilMcoil
Fgasp
Pi+1
cg (ycg)
Oil film
Figure 6 Free body diagram of ring cross section
simulation the section of thrust side (TS) is used Thegoverning equations for the ring motion are
119898119903
1198892119910cg
1198891199052= 119865119892oil + 119865119892asp + 119865119888frc minus 119865119897pre minus 119898119903119892
1198681199031198892120572
1198891199052= 119872119892oil +119872119892asp +119872119888frc +119872119897pre +119872119888oil
+119872119888asp minus 119870119903119905120572
119898119903
1198892ℎcg
1198891199052= 119865119892pre + 119865119892frc + 119865119888oil minus 119865119888asp
minus 1198651015840
119897pre + 119870119903119903 (ℎ1015840+ ℎ0)
(4)
where 119910cg and ℎcg are the axial and radial position of thecenter of gravity of the ring and120572 is the twist angle119898119903 119868119903 and119870119903119905 are ringmassmoment of inertia for toroidal rotation andcross-sectional torsional stiffness 119870119903119903 is the radial tensionstiffness ℎ1015840 is the reduction in ring radius at installation andℎ0 is the minimum ring-bore oil film thickness (119865tension =
119870119903119903(ℎ1015840+ ℎ0)) 119865 and119872 are the forces and moments acting on
the ring cross section (Figure 6) In (4) the first subscript forthe force and moment terms indicates location on the ring(119892 = groove 119888 = cylinder and 119897 = land) and the secondsubscript describes the source of the force or moment (oil =oil pressure asp = normal pressure due to asperity contactpre = gas pressure and frc = hydrodynamic or boundaryfriction) The torsional moment119872119903119905 is calculated as
119872119903119905 = 119870119903119905120572 (5)
For a complete ring with rectangular cross section the cross-sectional torsional stiffness (119870119903119905) is given by
119870119903119905 =1198641198873 ln (119863119889)3 (119863 + 119889)
(6)
where 119864 is the modulus of elasticity of piston ring 119887 is theaxial height of piston ring section 119889 is the inner diameterand 119863 is the outer diameter of piston ring The axial motionof a ring relative to piston can be expressed as
119910cg = 119910119901 + 119910119903119901
119889119910cg
119889119905=119889119910119901
119889119905+119889119910119903119901
119889119905
1198892119910cg
1198891199052=1198892119910119901
1198891199052+1198892119910119903119901
1198891199052
(7)
where 119910119901 is the axial position of the piston and 119910119903119901 is the axialposition of the ring related to the piston And 119910119901 can be given
Advances in Mechanical Engineering 5
52
Ges
chliff
en08 08
R04
R 04
3middot middot middot12 120583m3middot middot middot12120583m
45 ∘
30 ∘radicRz4
44middot middot middot66120583mradicRz 6Ground
R 03 max
R03
max
minus0005minus0050
First ring Second ringand third ring
Oil ring
04
max
04
max
35plusmn02
09 plusmn01
05plusmn005
145plusmn045
145plusmn045
02plusmn01
02plusmn01
45∘ plusmn5∘
45∘ plusmn5∘
35 ∘plusmn2 ∘
35∘ plusmn2∘
asymp35
3∘ plusmn 30998400
Figure 7 The geometry of the piston rings
out by the piston secondary motion together with the axialmotion Using a developed version of an existing ring packlubrication model Gamble et al [17] investigated the effectof piston secondary motion on the performance of a dieselengine piston ring pack in terms of gas flow and interringgas pressures For an example engine operating condition theeffect of secondarymotion on the ring packwas calculated fora number of ring gap positional combinationsThe secondarymotion and the positions of the ring gaps were shown to havean effect on the ring pack operating conditions such as oilfilm thickness friction wear oil transport and degradationAnd in order to determine the parameter 119910119901 the tilt of pistonand axial position are needed and those two parameters canbe calculated by iteration algorithm used in [17]
Forces and moment associated with land and groove gaspressure are calculated using pressure solutions from the gasdynamics submodel Forces and moments associated withoil pressure are obtained from the lubrication submodeland those associated with local asperity contact pressure arecalculated by asperity deformationmodel Ring axial positionand twist influence gas flow paths and the forces at the ring-groove interface Ring twist also affects the effective profilepresented by the ring face to the cylinder bore and thus affectsoil film thickness and ring friction The lubrication modelasperity deformation model and oil film squeezing model atring side and groove interface have been previously described[16 18]
The structure of the rings used in the piston is shownin Figure 7 Each ring is modeled as a single mass twisting(including pretwist angles) is considered The equations ofmotion which considers equilibrium condition of momentsand forces for each ring are solvedThe dynamic componentsof ringmotion are calculated using time integrationmethods
07
06
05
04
03
02
01
0
Hei
ght o
f bor
e (m
)
minus500E minus 05 500E minus 05 150E minus 04 250E minus 04
Deformation considering install prestressDeformation considering both of install prestress and thermalDeformation considering thermal
Deformation (m)
Figure 8 The bore deformation
The cylinder liner typically shows a deformation alongcylinder length axis and along cylinder circumference dueto bolting prestress and thermal load in the real conditionIn this study the deformation of bore in different caseshas been given by Figure 8 The mechanism of piston ringsealing is equivalent to a labyrinth seal where the gapclearances are determined by the position of the rings inthe groove considering the global movement and tilting ofthe piston [17] The Reynolds equations are solved iterativelyin each time step to determine the hydrodynamic pressuredistribution between ring running surface and liner All
6 Advances in Mechanical Engineering
0 90 180 270 360 450 540 630 720minus010
minus008
minus006
minus004
minus002
000
002
004
CA (deg)
Tilti
ng an
gle o
f pist
on (d
eg)
Figure 9 The tilting angle of piston during operation
minus008
minus006
minus004
minus002
000
002
004
006
008
First ring Second ring Oil ring
Crank angle (deg)0minus360 360
The p
ositi
on o
f rin
gs in
gro
ove (
mm
)
Figure 10 The position of rings in groove
relevant mechanisms are considered the calculation is donequasi-statically per time step The tilting angle of piston isgiven by Figure 9 And the motion of each ring in grooveduring operation is shown in Figure 10 and the thickness offilm oil between each ring face and bore is shown in Figure 11
32 Temperature Distribution Using the mathematicalmodel developed above the HTCs distribution in pistongrooveslands can be determined after getting the positionof each ring and the film thickness between each ring andbore Based on the determined HTCs in the top head pistonlandsgrooves and piston skirt the temperature distributionof the piston is predicted by FEA in ANSYS (Figures 12 and13) As shown in Figures 12 and 13 the temperature intensitydistribution decreases gradually from the head of the pistonto the bottom of the skirt A maximum temperature ofapproximately 392∘C is obtained on the head of the pistonat the combustion chamber chamfer edge (Figure 12) This
0 60 120 180 240 300 360 420 480 540 600 660 7200000
0005
0010
0015
0020
0025
Crank angle (deg)
Film
thic
knes
s (m
m)
First ringSecond ringOil ring
Figure 11 The film thickness of each ring
400350300250200
392∘CΔT
MX195∘C
156∘C134∘C
11689
4
147505
178116
208728
239339
269951
300562
331173
361785
392396
Figure 12 The temperature distribution of piston head
result is similar to that obtained on a similar type of pistonin an earlier study [19] The temperature decreases radicallytowards the outside and inside of piston The temperature is156∘C and 134∘C at the bottom of fire land and second landrespectively As it is shown in Figure 11 the temperaturedistribution in the skirt bolt and pin are lower than thepiston The maximum temperature is 1556∘C 250∘C and997∘C respectively
33TheMechanical Loads Theworking pistonnot only bearsa thermal load but also the high pressure of the fuel gasand the inertia force created by the reciprocating motionThe most strenuous condition of running the piston is themoment when the pressure in the combustion chamberreaches its maximum valueTherefore this study lays empha-sis on the stable stress at the combustion moment whenoperating at a stable speed
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
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Shock and Vibration
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Distributed Sensor Networks
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- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
Advances in Mechanical Engineering 5
52
Ges
chliff
en08 08
R04
R 04
3middot middot middot12 120583m3middot middot middot12120583m
45 ∘
30 ∘radicRz4
44middot middot middot66120583mradicRz 6Ground
R 03 max
R03
max
minus0005minus0050
First ring Second ringand third ring
Oil ring
04
max
04
max
35plusmn02
09 plusmn01
05plusmn005
145plusmn045
145plusmn045
02plusmn01
02plusmn01
45∘ plusmn5∘
45∘ plusmn5∘
35 ∘plusmn2 ∘
35∘ plusmn2∘
asymp35
3∘ plusmn 30998400
Figure 7 The geometry of the piston rings
out by the piston secondary motion together with the axialmotion Using a developed version of an existing ring packlubrication model Gamble et al [17] investigated the effectof piston secondary motion on the performance of a dieselengine piston ring pack in terms of gas flow and interringgas pressures For an example engine operating condition theeffect of secondarymotion on the ring packwas calculated fora number of ring gap positional combinationsThe secondarymotion and the positions of the ring gaps were shown to havean effect on the ring pack operating conditions such as oilfilm thickness friction wear oil transport and degradationAnd in order to determine the parameter 119910119901 the tilt of pistonand axial position are needed and those two parameters canbe calculated by iteration algorithm used in [17]
Forces and moment associated with land and groove gaspressure are calculated using pressure solutions from the gasdynamics submodel Forces and moments associated withoil pressure are obtained from the lubrication submodeland those associated with local asperity contact pressure arecalculated by asperity deformationmodel Ring axial positionand twist influence gas flow paths and the forces at the ring-groove interface Ring twist also affects the effective profilepresented by the ring face to the cylinder bore and thus affectsoil film thickness and ring friction The lubrication modelasperity deformation model and oil film squeezing model atring side and groove interface have been previously described[16 18]
The structure of the rings used in the piston is shownin Figure 7 Each ring is modeled as a single mass twisting(including pretwist angles) is considered The equations ofmotion which considers equilibrium condition of momentsand forces for each ring are solvedThe dynamic componentsof ringmotion are calculated using time integrationmethods
07
06
05
04
03
02
01
0
Hei
ght o
f bor
e (m
)
minus500E minus 05 500E minus 05 150E minus 04 250E minus 04
Deformation considering install prestressDeformation considering both of install prestress and thermalDeformation considering thermal
Deformation (m)
Figure 8 The bore deformation
The cylinder liner typically shows a deformation alongcylinder length axis and along cylinder circumference dueto bolting prestress and thermal load in the real conditionIn this study the deformation of bore in different caseshas been given by Figure 8 The mechanism of piston ringsealing is equivalent to a labyrinth seal where the gapclearances are determined by the position of the rings inthe groove considering the global movement and tilting ofthe piston [17] The Reynolds equations are solved iterativelyin each time step to determine the hydrodynamic pressuredistribution between ring running surface and liner All
6 Advances in Mechanical Engineering
0 90 180 270 360 450 540 630 720minus010
minus008
minus006
minus004
minus002
000
002
004
CA (deg)
Tilti
ng an
gle o
f pist
on (d
eg)
Figure 9 The tilting angle of piston during operation
minus008
minus006
minus004
minus002
000
002
004
006
008
First ring Second ring Oil ring
Crank angle (deg)0minus360 360
The p
ositi
on o
f rin
gs in
gro
ove (
mm
)
Figure 10 The position of rings in groove
relevant mechanisms are considered the calculation is donequasi-statically per time step The tilting angle of piston isgiven by Figure 9 And the motion of each ring in grooveduring operation is shown in Figure 10 and the thickness offilm oil between each ring face and bore is shown in Figure 11
32 Temperature Distribution Using the mathematicalmodel developed above the HTCs distribution in pistongrooveslands can be determined after getting the positionof each ring and the film thickness between each ring andbore Based on the determined HTCs in the top head pistonlandsgrooves and piston skirt the temperature distributionof the piston is predicted by FEA in ANSYS (Figures 12 and13) As shown in Figures 12 and 13 the temperature intensitydistribution decreases gradually from the head of the pistonto the bottom of the skirt A maximum temperature ofapproximately 392∘C is obtained on the head of the pistonat the combustion chamber chamfer edge (Figure 12) This
0 60 120 180 240 300 360 420 480 540 600 660 7200000
0005
0010
0015
0020
0025
Crank angle (deg)
Film
thic
knes
s (m
m)
First ringSecond ringOil ring
Figure 11 The film thickness of each ring
400350300250200
392∘CΔT
MX195∘C
156∘C134∘C
11689
4
147505
178116
208728
239339
269951
300562
331173
361785
392396
Figure 12 The temperature distribution of piston head
result is similar to that obtained on a similar type of pistonin an earlier study [19] The temperature decreases radicallytowards the outside and inside of piston The temperature is156∘C and 134∘C at the bottom of fire land and second landrespectively As it is shown in Figure 11 the temperaturedistribution in the skirt bolt and pin are lower than thepiston The maximum temperature is 1556∘C 250∘C and997∘C respectively
33TheMechanical Loads Theworking pistonnot only bearsa thermal load but also the high pressure of the fuel gasand the inertia force created by the reciprocating motionThe most strenuous condition of running the piston is themoment when the pressure in the combustion chamberreaches its maximum valueTherefore this study lays empha-sis on the stable stress at the combustion moment whenoperating at a stable speed
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Antennas andPropagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
6 Advances in Mechanical Engineering
0 90 180 270 360 450 540 630 720minus010
minus008
minus006
minus004
minus002
000
002
004
CA (deg)
Tilti
ng an
gle o
f pist
on (d
eg)
Figure 9 The tilting angle of piston during operation
minus008
minus006
minus004
minus002
000
002
004
006
008
First ring Second ring Oil ring
Crank angle (deg)0minus360 360
The p
ositi
on o
f rin
gs in
gro
ove (
mm
)
Figure 10 The position of rings in groove
relevant mechanisms are considered the calculation is donequasi-statically per time step The tilting angle of piston isgiven by Figure 9 And the motion of each ring in grooveduring operation is shown in Figure 10 and the thickness offilm oil between each ring face and bore is shown in Figure 11
32 Temperature Distribution Using the mathematicalmodel developed above the HTCs distribution in pistongrooveslands can be determined after getting the positionof each ring and the film thickness between each ring andbore Based on the determined HTCs in the top head pistonlandsgrooves and piston skirt the temperature distributionof the piston is predicted by FEA in ANSYS (Figures 12 and13) As shown in Figures 12 and 13 the temperature intensitydistribution decreases gradually from the head of the pistonto the bottom of the skirt A maximum temperature ofapproximately 392∘C is obtained on the head of the pistonat the combustion chamber chamfer edge (Figure 12) This
0 60 120 180 240 300 360 420 480 540 600 660 7200000
0005
0010
0015
0020
0025
Crank angle (deg)
Film
thic
knes
s (m
m)
First ringSecond ringOil ring
Figure 11 The film thickness of each ring
400350300250200
392∘CΔT
MX195∘C
156∘C134∘C
11689
4
147505
178116
208728
239339
269951
300562
331173
361785
392396
Figure 12 The temperature distribution of piston head
result is similar to that obtained on a similar type of pistonin an earlier study [19] The temperature decreases radicallytowards the outside and inside of piston The temperature is156∘C and 134∘C at the bottom of fire land and second landrespectively As it is shown in Figure 11 the temperaturedistribution in the skirt bolt and pin are lower than thepiston The maximum temperature is 1556∘C 250∘C and997∘C respectively
33TheMechanical Loads Theworking pistonnot only bearsa thermal load but also the high pressure of the fuel gasand the inertia force created by the reciprocating motionThe most strenuous condition of running the piston is themoment when the pressure in the combustion chamberreaches its maximum valueTherefore this study lays empha-sis on the stable stress at the combustion moment whenoperating at a stable speed
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Antennas andPropagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
Advances in Mechanical Engineering 7
Maximum = 1556∘C
Minimum = 956∘C
(a) Skirt
Maximum = 2505∘C
Minimum = 98∘C
(b) Connection bolt
Maximum = 997∘C
Minimum = 98∘C
(c) Pin
Figure 13 The temperature distribution of piston skirt connect bolt and piston pin
Crank angle (deg) Crank angle (deg)
Fire land
Fire land
Second land
Second land
00
Gas
pre
ssur
e (Pa
)
0 60 120 180 240 300 360 420 280 540 600 660 720 0 60 120 180 240 300 360 420 280 540 600 660 720
25
20
15
10
05
times107
00
Gas
pre
ssur
e (Pa
)
25
20
15
10
05
times107
Third land
Third land
The first grooveThe second grooveThe third groove
The first grooveThe second grooveThe third groove
Figure 14 The pressure in lands and grooves versus crank angle
(1) Gas Pressure Gas pressure is primary loaded on the topof head However the piston lands and grooves are alsoloaded The gas pressure in the chamber is calculated fromGT-POWER based on the design parameters of the newpiston The pressure acts on ring lands and grooves arecalculated using a piston ring dynamics program Based onthe ring dynamics model developed above the gas pressurein lands and grooves are calculated (Figure 14)
(2) Reciprocating Inertial Force Due to the reciprocatingmotion of piston in the cylinder the inertial force of thepiston cannot be ignored in the mechanical analysis Basedon the engine dynamics the reciprocating inertial force 119875119895is related to the acceleration of the piston The force actionline is parallel to the center line of the cylinder Because
the inertial force direction is opposite to the accelerationthe effect of gas pressure on piston might be subducted Thereciprocating inertial force is calculated as
119875119895 = minus119898119895 (1 + 120582) 1198771205962 (8)
The acceleration at the moment of combustion is given as
119886 = 1198771205962(cos120572 + 120582 cos 2120572) (9)
where 120596 is the angular velocity 120596 = 11989912058730 119899 is the rotationalspeed rpm and 120582 is the ratio of crank radius119877 and rod length119871
34 Thermomechanical Fatigue Life Prediction The highcycle fatigue prediction is based on the thermomechanical
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Antennas andPropagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
8 Advances in Mechanical Engineering
Maximum = 330MPa
0147E + 07
0379E + 08
0744E + 08
0111E + 09
0147E + 09
0184E + 09
0220E + 09
0257E + 09
0293E + 09
0330E + 09
Figure 15 The von Mises stresses in piston head
35101
0500E + 08
0100E + 09
0150E + 09
0200E + 09
0250E + 09
0300E + 09
0350E + 09
0400E + 09
0450E + 09
Maximum = 450MPa
Figure 16 The von Mises stresses in piston head
analysis results of alternating conditions The first conditionis the moment when the piston is at the top dead point afteroutbreak and the alternate condition is when the piston isat the bottom dead point in the exhaust stroke The Haighdiagram is modified according to the magnitude of the stressgradient nodal temperature andmodification factors at eachnode The mean and alternating stresses resulting from thealternating conditions are computed at each node then theHCF safety factor for each node is attained
The selection of the displacement boundary conditionsignificantly affects the finite element analysis A symmetricalrestraint is applied on the symmetry plane because a quarterof a symmetric piston is modeled Three degrees of freedomon the bottom of the rod of the piston assembly are restrainedto hold the piston in a static condition
In this analysis a multilinear kinematic hardening modelis used to account for material nonlinearity The followingload cases are defined to simulate different stages of the workcycle
(1) application of the pretension force of the bolt to themodel
(2) application of thermal loads (temperature) to themodel
(3) application of inertia loads (piston acceleration) to themodel
(4) application of maximum pressure of combustiongases to the top head the lands pressures and groovespressures to the model
4 Results and Analysis
Thedistribution of equivalent vonMises stresses in the pistonhead after application of thermal loads inertia loads pressureof combustion gases and ring region pressure is shown inFigure 15 In the cooling oil chamber closed to the firstgroove the induced stresses are high 330MPa due to thereduction of piston wall thickness and stress concentrationeffect Figure 16 shows the distribution of equivalent vonMises stresses in the piston skirtThe areas around the contactregions of piston skirt and piston pin are subjected to severestresses 450MPa (Figure 16)
The commercial software FE-SAFE is used to calculatethe HCF safety factorsThe contour of the HCF safety factorsin the piston head and pin is shown in Figure 17 The safetyfactors in the piston head and pin are more than 18 Thisindicates that the design of those components can meetthe life limitation Variable tensile and compressive meanstresses are observed in different regions of the piston skirt(Figure 18) The maximum compressive mean stresses dueto mechanical loads are observed in the piston pin hole(114MPa) The maximum tensile stresses are located on thecontact face between connection bolt and skirt (145MPa)
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Antennas andPropagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
Advances in Mechanical Engineering 9
1881
1894
1908
1921
1934
1947
196
1974
1987
2
Figure 17 The safety factor distribution in head and pin
minus113196
minus84478
minus5576
minus27042
1676
30394
59113
87831
116549
145267
Figure 18 The mean stresses distribution in piston skirt
144
1105
102
1008
1118
1228
1339
1449
1559
1669
178
189
2
Figure 19 The safety factor distribution in piston skirt
The safety factors at the inner contact areas of pin-pin holeand bolt-skirt are lower than other regions (Figure 19) theminimum value is just 102 which does not reach the strengthrequirement of 15
5 Conclusions
This study performs a detailed thermomechanical stressanalysis on a diesel engine piston Temperature distribution
is determined from thermal analysis In order to calculatethe HCF safety factor the commerce software FE-SAFE isused A piston ring dynamics calculation is used to determinethe thickness of lubrication oil film when calculating themagnitude of the heat transfer coefficient (HTC) in thermalloads analysis The gas pressure of ring lands and ringgrooves in mechanical analysis is calculated using a pistonring dynamics model The prediction procedure designedin this study is the combination of lubrication thermaland structure analysis The results obtained using this newmethod provide a guideline for further optimizing the designand manufacture of new pistons Future work will focus onexperimental validation
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
Thepresent research has been funded by theNational NaturalScience Foundation of China (Grant no 51375104) and theFundamental Research Funds for the Central Universities(Code HEUCFZ1117) the authors would like to sincerelyexpress their appreciation And the authors greatly thankMelanie Koleini in Washington University for her assistancein checking and refining the language
References
[1] F S Silva ldquoFatigue on engine pistonsmdasha compendium of casestudiesrdquo Engineering Failure Analysis vol 13 no 3 pp 480ndash4922006
[2] W Zhang CWei Z Su J Liu and J Xiang ldquoStudy on forecast-ing of fatigue life for aluminum alloy piston of diesel enginerdquoZhongguo Jixie GongchengChina Mechanical Engineering vol14 no 10 pp 865ndash867 2003
[3] M T Abbes P Maspeyrot A Bounif and J Frene ldquoA thermo-mechanical model of a direct injection diesel engine pistonrdquoProceedings of the Institution ofMechanical Engineers PartD vol218 no 4 pp 395ndash409 2004
[4] Y Liu Y Wang X Men and F Lin ldquoAn investigation on pistonpin seat fatigue life on themechanical fatigue experimentsrdquoKeyEngineering Materials vol 324-325 pp 527ndash530 2006
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Antennas andPropagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
10 Advances in Mechanical Engineering
[5] S Y Liu F H Lin Y Z Qin and ZMWang ldquoPiston durabilityresearch based on the pin-bore profile designrdquo Chinese InternalCombustion Engine Engineering vol 28 no 1 pp 46ndash50 2007
[6] Y Wang Y Dong and Y Liu ldquoSimulation investigation onthe thermo-mechanical coupling of the QT 300 pistonrdquo inProceedings of the 2nd International Conference on InformationandComputing Science (ICIC rsquo09) vol 4 pp 77ndash80ManchesterUK May 2009
[7] YWang Y Liu andH Shi ldquoSimulation and analysis of thermo-mechanical coupling load and mechanical dynamic load for apistonrdquo in Proceedings of the 2nd International Conference onComputer Modeling and Simulation (ICCMS rsquo10) pp 106ndash110Sanya China January 2010
[8] MAyatollahi R FMohammadi andHR Chamani ldquoThermo-mechanical fatigue life assessment of a diesel engine pistonrdquoInternational Journal of Automotive Engineering vol 1 no 4 pp256ndash266 2011
[9] S R LampmanAsmMetals Handbook Volume 19mdashFatigue andFracture ASM International 1997
[10] T Gocmez A Awarke and S Pischinger ldquoA new low cyclefatigue criterion for isothermal and out-of-phase thermome-chanical loadingrdquo International Journal of Fatigue vol 32 no4 pp 769ndash779 2010
[11] R Minichmayr M Riedler G Winter H Leitner and WEichlseder ldquoThermo-mechanical fatigue life assessment of alu-miniumcomponents using the damage ratemodel of SehitoglurdquoInternational Journal of Fatigue vol 30 no 2 pp 298ndash3042008
[12] M M Rahman A K Ariffin N Jamaludin S Abdullah andM M Noor ldquoFinite element based fatigue life prediction of anew free piston engine mountingrdquo Journal of Applied Sciencesvol 8 no 9 pp 1612ndash1621 2008
[13] P Gudimetal and C V Gopinath ldquoFinite element analysis ofreverse engineered internal combustion engine pistonrdquo AsianInternational Journal of Science and Technology in Productionand Manufacturing Engineering vol 2 no 4 pp 85ndash92 2006
[14] X Lu Q Li W Zhang Y Guo T He and D Zou ldquoThermalanalysis on piston of marine diesel enginerdquo Applied ThermalEngineering vol 50 no 1 pp 168ndash176 2013
[15] X-Q Lu T He D-Q Zou Y-B Guo and W-Y Li ldquoThermalanalysis of composite piston in marine diesel engine based oninverse evaluation method of heat transfer coefficientrdquo ChineseInternal Combustion Engine Engineering vol 33 no 4 pp 71ndash76 2012
[16] T Tian L B Noordzij V W Wong and J B Heywood ldquoMod-eling piston-ring dynamics blowby and ring-twist effectsrdquoJournal of Engineering for Gas Turbines and Power vol 120 no4 pp 843ndash854 1998
[17] R J Gamble M Priest R J Chittenden and C M TaylorldquoPreliminary study of the influence of piston secondary motionon piston ring tribologyrdquo Tribology Series vol 38 pp 679ndash6912000
[18] R Keribar Z Dursunkaya and M F Flemming ldquoIntegratedmodel of ring pack performancerdquo Journal of Engineering for GasTurbines and Power vol 113 no 3 pp 382ndash389 1991
[19] D-M Lou Z-Y Zhang and L-L Wang ldquoHeat transferboundary condition and thermal load of combined-piston forlocomotive diesel enginesrdquo Journal of Tongji University vol 33no 5 pp 664ndash667 2005
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Antennas andPropagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
- Thermomechanical fatigue life prediction for a marine diesel engine piston considering ring dynamics
-
- Recommended Citation
- Authors
-
- tmp1423617748pdfEWJA4
-
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mechanical Engineering
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Distributed Sensor Networks
International Journal of
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
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