nonlinear incremental thermal stress strain … incremental thermal stress strain analysis ... (etl...
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Nonlinear IncrementalThermal Stress Strain AnalysisPortugues Dam
Thermal Analysis Project TeamDavid Dollar Project Manager (USACE, Jacksonville District)
Ahmed Nisar (MMI Engineering)
Paul Jacob (MMI Engineering)
Charles Logie (MMI Engineering)2005 Tri-Services Infrastructure Conference August, 2005
Objectives of Study
� Long term stable temperature response� Location and behavior of contraction joints� Potential for cracking� Significance of material properties
Project Approach
� Phase I - Preliminary Analysis• Model testing (concurrent with dam design)• Parametric study to determine significant
parameters
� Phase II – Final Analysis• Final dam geometry• Final material properties
Heat loss (or gain) toatmosphere through uppersurface of (most recent lift)
Heat loss (or gain) to atmospherethrough upper part of upstream face
Internal heatgeneration
Solar Radiation
Heat loss (or gain )toatmosphere through dam crest
Heat loss (or gain) toatmosphere throughdownstream face
Heat loss (or gain) toatmosphere from foundationHeat loss (or gain) to water
from foundation
Heat loss (or gain) towater through lower partof upstream face
Heat loss (or gain) to atmosphereon north side (most recent lift)
Heat loss (or gain) toatmosphere through uppersurface of (most recent lift)
Heat loss (or gain) to atmosphereon south side (most recent lift)
Heat loss (or gain) to atmosphereon north side (previously placedlifts)
Heat loss (or gain) toatmosphere on south side(previously placed lifts)
Internal heatgeneration(previously placedlifts)
Internal heatgeneration(most recent lift)
Solar Radiation
Analysis Procedure
Analysis Approach(ETL 1110-2-365)
� De-coupled thermal/stress analysisusing ABAQUS/Standard
� Combination 2D and 3D analysis� Incremental placement of lifts� Material nonlinearity� Boundary conditions
2D Dam Geometry
3D Dam Geometry
Thermal Material Properties
� Roller compactedconcrete– Non linear internal
heat generation(heat of hydrationfrom adiabatictemperature rise)
– All other propertieslinear (Cp, k, γ)
� Linear (uniform)foundation material
0
10
20
30
40
50
60
0 10 20 30 40 50 60
Time (Days)
Tem
pera
ture
Ris
e (D
egre
es, F
)
tCH p ∆
∆⋅⋅= θγ& (BTU/in3/day)
Structural Material Properties
� General nonlinearproperties for RCC– Modulus– Shrinkage– Creep/Aging
� Linear foundationmaterial
0
20
40
60
80
0 50 100 150 200 250 300 350 400
Time (days)
Shrin
kage
Str
ain
(mill
iont
hs)
Analysis FitTest Data
0.0E+00
1.0E+06
2.0E+06
3.0E+06
4.0E+06
5.0E+06
0 50 100 150 200 250 300 350 400
Time (days)
Elas
tic M
odul
us (p
si)
)
Analysis FitTest Data
0
200
400
600
800
1000
0 50 100 150 200 250 300 350 400 450
Time (days)
Test DataVerification 6Verification 10Verification 11
Boundary Conditions
� Thermal analysis– Time/temperature dependent transfer films– Solar radiation flux– Heat loss to foundation
� Structural analysis– Foundation constraint– 3D Model - contact at construction joints
Average Solar Radiation (1961-1990)(every hour for 365 days)
0
200
400
600
800
1000
1200
1400
1600
0 2 4 6 8 10 12 14 16 18 20 22 24
Hour
Sola
r Rad
iatio
n (w
att-h
our p
er s
quar
e m
eter
)
Extraterrestrial Horizontal
Global Horizontal
365 lines of data
Average Data (1961 - 1990) 15th Day of Each MonthGlobal Horizontal (Normalized to Max)
0
0.2
0.4
0.6
0.8
1
1.2
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 0:00
Hour
Sola
r Rad
iatio
n (w
att-h
our p
er s
quar
e m
eter
)
JanFebMarAprMayJuneJulyAugSepOctNovDec
Average Maximum Radiation
Zero Solar Radiation
15th Day of 2004 Normalized to Max Temp of the Day
0.7
0.8
0.9
1
1.1
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
Time of Day
Tem
pera
ture
(deg
F)
1/15/20042/16/20043/15/20044/15/20045/15/20046/16/20047/15/20048/15/20049/14/200410/19/200411/18/200412/14/2004
Average Minimum Temperature
Average Maximum Temperature
0.95 x Average MaximumTemperature
Solar Radiation
Lift 50
Lift 100
Lift 150
Lift 200
End of Construction
1-Year After Construction
Run 10monthly temperature variation
with solar radiation
Run 2monthly temperature variation
without solar radiation
Phase IExampleResults
EL 220
EL 200
EL 000
EL 050
EL 100
EL 150
(a) Solar Radiation not Included (Run 2)
(b) Solar Radiation Included (Run 10)
EL 000 Mid-Point
EL 050 Mid-Point
EL 100 Mid-Point
EL 150 Mid-Point
EL 200 Mid-Point
60
70
80
90
100
110
120
130
0 100 200 300 400 500Time (days)
Tem
pera
ture
(Deg
rees
, F)
60
70
80
90
100
110
120
130
0 100 200 300 400 50Time (days)
Tem
pera
ture
(Deg
rees
, F)Phase I
ExampleResults
After Placement of 50 Lifts After Placement of 100 Lifts After Placement of 150 Lifts After Placement of 200 Lifts
At the End of Construction 1 year after the Construction 5 years after the Construction 10 years after the Construction
Phase I Example Results
Simplified Analysis
� Tatro & Schrader� ACI 207.2R-95� ETL 1110-2-542
Simplified Analysis
Results Status (Phase II) - Thermal
Results Status Phase II - Stress
Remaining Steps
� Thermal component of analysis are nearingcompletion
� Stress analysis– Construction sequence completed– Long term cool down requires coarser mesh to
achieve adequate computational performance
� Coarse mesh mapping of thermal results isunderway – reasonable comparison is beingobtained
Mesh Mapping Methods
Analytical Management� Management of model size
– Geometry (lift size)– Load time step resolution
(solar radiation/daily temperature variation)– Long duration for dam cool down (years
rather than months)
� 3rd party material model usage– It would be more convenient to use an internal
material model in ABAQUS
Analytical Management
� Software bugs– Debugging vendor software– Memory management issues
(porting of software to non native platforms)
� Software limitations (and workarounds)– Mesh mapping to reduce computational
overheads of stress analysis phase of work– Selection of contact algorithms