crash analysis 240509

8/18/2019 Crash Analysis 240509

1/39

ANALYSIS OF AN AUTOMOBILE


2/39

WHY ANALYSIS ??


3/39

STRUCTURAL ANALYSIS

Structural analysis comprises the set of physical laws and mathematics

required to study and predict the behavior of structures

This analysis is used to judge the ultimate loadsThis analysis incorporates the fields of mechanics and dynamics

Examples are buildings, bridges, aircraft, train wagon, car and ships

This is theoretical analysis and deals with computation ofdeformations, internal forces and stresses

Basically structural analysis is alienated in below mentioned veritiesof analysis

Strength of materials methodElasticity methodFinite element method


4/39

ANALYSIS OF AN AUTOMOBILE

LINEAR STATIC

CRASH

NOISE, VIBRATION, AND HARSHNESS ANALYSIS

DYNAMIC

NON LINEAR STATIC

BUCKLING

THERMALFATIGUE OR DURABILITY

OPTIMIZATION CFD


5/39

LINEAR STATIC ANALYSIS

LINEAR This analysis deals with stress strain diagram! " # $E

STATIC There are two conditions for static analysis

%& with dead load condition

'f ( dT #)*& Equilibrium condition

+ Fx, Fy, F-&.+ /x,/y,/-)

0ractical applications 1erospace, 1utomobile, 2ffshore and civil engineering

Softwares used 3astran,1nsys,1baqus,45deas 36,7adioss,cosmos,89,

pro5mechanica, :atia etc


6/39

NON LINEAR ANALYSIS

4n this analysis there are three parameters

Geomentri!" 'eals with the deflection

; # 0


7/39

FATIGUE OR DURABILITY ANALYSIS

calculations for life of the structure when subjected to repetitive load

S53 curve or $53 curves gives the basic >nowledge for calculations of fatigue

'amage @ % safe'amage A % fail

1pplication 1ll 1utomobile componentsSoftwares used /S: Fatigue!FE/F1T,FE S1FE,


8/39

DYNAMIC ANALYSIS

'ynamic analysis can be done in two ways

/CD .:C.>C8#Ft&

Free (natural frequency)# The frequency with which any object will vibrate noexternal force applied&*ore The frequency with which object will vibrate with response to externalforce applied A''"i!tion% # subjected to force ( displacement ( velocity ( acceleration varyingith respect to rate of frequency

Softwares used 3astran, 1nsys, 1baqus, /atlab, 45deas36, 7adioss


9/39

NOISE,VIBRATION,AND HARSHNESS ANALYSIS

1lso >nown as noise and vibration 3GH&, is the study and modification of the noise

and vibration characteristics of vehicles, particularly cars and truc>s

Iarshness is a subjective quality, and is measured either via JjuryJ evaluations, orwith analytical tools that provide results reflecting human subjective impressions

4nterior 3HI deals with noise and vibration experienced by the occupants of thecabin, while exterior 3HI is largely concerned with the noise radiated by the vehicle,and includes drive5by noise testing

4n some cases the 3HI engineer is as>ed to change the sound quality, i!e! addingor subtracting particular harmonics, rather than ma>ing the car quieter


10/39

BUCKLING ANALYSIS

Buc>ling &*

1pplicable only for compressive load columns&

Slender beam G sheet metal parts

Bending stiffness@@@axial stiffness


11/39

THERMAL ANALYSIS

1pplications Engine, 7adiator , Exhaust System, 0ower 0lants, Satellite 'esign

Softwares 8sed 1nsys,3anstran,1baqus,45deas 36


12/39

OPTIMIZATION

Basically in two categories 9eometrical 0arameters Shape optimi-ation

For optimi-ing geometrical parameters, there is no particular softwareBut we can set some pre defined parameters within specified limits

4n shape case usually restricted to only linear static G normal mode of dynamics

4n this software can give hint for addition or removal of geometry

1pplications prototype designing

Softwares used 2ptistruct, Tosca, 3astran, 1nsys


13/39

COMPUTATIONAL FLUID DYNAMICS(CFD&:omputational fluid dynamics :F'& is the branch of fluid mechanics which uses

3umerical methods to analy-e fluid dynamics problems!F"+i& Me!ni%

F"+i& St!ti% (H-&ro%t!ti%) F"+i& D-n!mi%

Fluid at rest Easy from calculation point of view 3o variation wrt time, less realistic view


14/39

CRASH ANALYSIS

/143 the structural integrity of the component

PEDESTRAIN

To find the effects of crash on human body and ma>ing the ride safe for driveras well as passengers!


15/39

CRASH TEST

1 crash test is a form of destructive testing usually performed in order to ensuresafe design standards in :rashworthiness and crash compatibility for automobilesor related components

:rash tests are conducted under rigorous scientific and safety standards! Eachcrash test is very expensive so the maximum amount of data must be extractedfrom each test! 8sually, this requires the use of high5speed data5acquisition, atleast one triaxial accelerometer and a crash test dummy

:rash test integrates the biomechanics to study about safety of occupantsMain tests in the Crash analysis of the car is

Front impact test7ear impact testSide impact test2ffset impact test0ole or street light impact test0edestrian impact test


16/39

BIO MECHANICS

The application of mechanical principles to living organisms! This includesbioengineering, the research and analysis of the mechanics of livingorganisms and the application of engineering principles to and from biologicalsystem

Thermodynamics,continuum mechanics and mechanical engineering disciplinessuch as fluid mechanics and solid mechanics, play prominent roles in the study ofbiomechanics! By applying the laws and concepts of physics, biomechanicalmechanisms and structures can be simulated and studied!

http://en.wikipedia.org/wiki/File:Penguinu.jpg


17/39

CRASH DUMMY

:rash test dummies are full5scale anthropomorphic test devices 1T'& that

simulate the dimensions, weight proportions and articulation of the human body instrumented to record data about the dynamic behavior of the 1T' insimulated vehicle impacts9athers the information of variables such as velocity of impact, crushing force,bending, folding, or torque of the body, and deceleration rates during a collisionfor use in crash tests! They remain indispensable in the development of and

ergonomics in all types of vehicles, i!e! from automobiles to aircraft.Bio74' is a dummy designed to assess the effects of a rearimpact

:71B4 is a child dummy used to evaluate the effectivenessof child restraint devices

S4' is the side impact dummyTI27 is an advanced male dummy

The dummies contain three types of sensors 1ccelerometers


18/39

FRONT IMPACT

Frontal crash testing For frontal crash test, the car is driven at a speed of =Mmiles per hour into a wall! all resembles another car driving at a same speed!This testing is mainly done to determine the impact of head collision! The testingarea is fitted with a camera that records the action or impact of collision


19/39

REAR IMPACT

44IS is the only 8S organi-ation to asses rear crash protection!Both static and motiontests are required for the 44IS to evaluate the rear crash protection! 4n the static one, acrash test dummy si-ed as an average adult male is put in the driving seat which is tiltedat about *M degrees! The head restraint should be =!M inches or less from the top of thehead and less than four inches from the bac> of the head! 4f it is adjustable which inmost cases is&, measurements are ta>en in both the down position and the most

favorable position


20/39

SIDE IMPACT

Side impact crash testing 4n side impact crash test, the car is driven against atrolley of %,=NO >g that slides with the sides of the car! The trolley is composed ofaluminum to imitate another vehicle bumper! The fitted cameras record the impactof collision from the sides of the car


21/39

OFFSET IMPACT

4n the frontal offset impact test a vehicle is aligned with a rigid barrier with a

deformable aluminum face so that P)Q of the width of the vehicle stri>es thebarrier on the driver?s side

The vehicle runs into the barrier at NP >m(h P) mph&, in order to measure andevaluate the impact on the dummies? head, chest, and legs 5 as well as to chec>the condition of the deformed vehicle! Because a smaller portion of the vehicle?sstructure sustains the force, the impact on the dummy is wea>er than in a fullfrontal impact


22/39

STREET LIGHT OR POLE IMPACTEuro 3:10 introduced the ?pole? test in *))) to assess the degree of protection

offeredThe car is propelled front and sideways at %Omph *R>ph& into a rigid pole! Thepole is relatively narrow, and usually penetrates the side of the car deeply


23/39

PEDESTRIAN IMPACTEstimates injuries to pedestrians struc> by a vehicle travelling

at P)>m(h it consists of dummy components projected at the vehicle front and bonnet toevaluate injury ris> for the head of an adult and child, upper leg and >nee.


24/39

ROLL OVER

7oll5over Tests which tests a car?s ability specifically the pillars holding the roof& to

support itself in a dynamic impact! /ore recently dynamic rollover tests have beenproposed as opposed to static crush testing video&


25/39

MESHING AND MESHING ELEMENTS

Meshing method of reducing degrees of freedom from infinite to finite with help ofdiscreti-ation

This is the input for crash analysis software

asic !eshing notations are

3odes and elements

3odes are the vertices of the elements

Types of elements

"-D ele!ents element shape is line

#-D ele!ents shape is quad, tri

$-D ele!ents shape is tetra, penta,hex,pyramid


26/39

CRASH AVOIDANCE SYSTEMS:rash avoidance systems and devices help the driver and help the vehicle itself to

avoid a collision! 4t includes the fallowing functionsThe vehicle?s headlamps, reflectors, and other lights and signalsThe vehicle?s bra>es, steering, and suspension systems 1 subset of crash avoidance is %ri&er assistance systems, which help the driver todetect ordinarily5hidden obstacles and to control the vehicle! 4t includesTraction control systems which restore traction if driven wheels begin to spin

Tire pressure monitoring systems or 'eflation 'etection Systems7everse bac>up sensors, which alert drivers to difficult5to5see objects in their pathwhen reversingElectronic Stability :ontrol, which intervenes to avert an impending loss of control bra>ing systemsElectronic bra>e force distribution systems:ornering Bra>e :ontrol systemsEmergency bra>e assist systemsForward :ollision arning Systems'ynamic Bra>e :ontrol systems


27/39

SENSOR ROLE

:rash sensors collect the data necessary to ma>e decisions about air bagdeployment!:rash sensors measure how quic>ly a vehicle slows down in a frontal crash oraccelerates to the side in a side5impact crash! Some vehicles are equipped with asensing system designed to detect the onset of a rollover crash!Frontal crash sensors may be located in the front of the vehicle near the engine,

in the passenger compartment, or sometimes in the electronic control unit E:8&!Side5impact crash sensors may be located in the E:8, the door, the doorsill, orbetween the front and rear doors!7ollover crash sensors may be located in the E:8 or at the vehicle?s center ofgravity!Severe or panic bra>ing alone cannot cause an air bag to deploy air bags

deploy only in crashes


28/39

Nissan %esign combines radar sensors and a computer system to judge a car?s

speed and the distance to the vehicle in front

Toyota %esign The 1H/, or Jaround view monitor,J shows what?s surrounding thecar from all around, putting together photo images from the cameras to helpdrivers steer into tight par>ing spotsvery useful in a crowded country li>e apan

Toyota %esign 4ntelligent 0ar>ing 1ssist system, in which the car par>s by itself even if the driver has no hands on the steering wheel calculating from its built5in computer, steering sensor and a tiny camera in therear the proper route into a par>ing spot

RATIONALISATION IN DESIGNING THE SENSORS


29/39

SAFETY MEASURESSeatbelts limit the forward motion of an occupant, stretch to slow down the occupant?s

deceleration in a crash, and prevent occupants being ejected from the vehicle 1irbags inflate to cushion the impact of a vehicle occupant with various parts of thevehicle?s interior into granules with minimally sharp edges, rather than splintering into jaggedfragments as ordinary glass does:rumple -ones absorb and dissipate the energy of a collision, displacing and diverting itaway from the passenger compartment and reducing the impact force on the vehicleoccupantsSide impact protection beams

:ollapsible steering columns reduce the ris> and severity of driver impalement on thecolumn in a frontal crashpedestrian protection systems0adding of the instrument panel and other interior parts of the vehicle li>ely to be struc>by the occupants during a crash


30/39

AIR CUSHION RESTRAINT SYSTEM

1irbags were created to prevent a driver and(or passenger from hitting the

interior structure of the vehicle in a car accident! hen an airbag deploys, itprotects the occupants from moving forward into the steering wheel ordashboard

airbag must inflate quic>ly, it can deploy at an extreme force, typically at aspeed of %)) miles per hour!

1irbag is a gas generator containing a mixture of nan=, U32=, and Sio*

The more complex sensors, called /icro5 /achined 1ccelerometers aremounted inside the control module, or airbag brain itself! These actuallymeasure the speed and severity of the crash

control module detects true crash, and it will send an impulse to the igniter

1fter deflation of the airbag, Simply open the doors or windows to ventilatethe vehicle

3ow a days head protecting air bags also being fitted in cars


31/39

SEAT BELTS AND LATCHES

es child safety seat installation easierVwithout usingseat belts

Fasten the child safety seatWs lower attachments to the vehicleWs lower anchors!Tighten and adjust according to the instructions and chec> for a secure fit


32/39

/HAT IS NCAP AND ITS ROLES

3:10 roles

4t executes the fallowing tests on the costumer?s vehicle

safety and child restraint systemsrollover injury ris>vehicle to vehicle compatibility

airbag system performanceoccupant injury tolerancesblunt traumatic aortic injury T14&side5impact injury patternscrash investigation variablesautomotive fire safety

NCAP # NE/ CAR ASSESSMENT PROGRAM

2rgani-ation, that deals with biomechanics research focuses on reducingtransportation5related injuries and fatalities!


33/39

NCAP AGENCIES

1714

1utomotive 7esearch 1ssociation of 4ndia

44IS The 4nsurance 4nstitute for Iighway Safety

3:10 8S 1merican 3ew :ar 1ssessment 0rogram

F/HSS Federal motor vehicle safety standards

3ITS1 3ational Iighway Traffic Safety 1dministration

Euro 3:10 European 3ew :ar 1ssessment 0rogram

13:10 1ustralian 3ew :ar 1ssessment 0rogram

31SH1 3ational 1gency For 1utomotive Safety 1nd Hictim?s 1idapan


34/39

CRASH TEST RATINGS

The most significant safety determinant is X X


35/39

DESIGN CONSIDERATIONS

Body Structures according to aerodynamics

0rovision of Structural 4ntegrity

2ptimum stiffness

:ontrolled energy absorption during crashSufficient durability A%)years&

Sufficient openings in hollow parts

give access and drainage of anticorrosion

chemicals and paints during

/anufacturing feasibility 3ecessary access for welding tools


36/39

SUITABLE MATERIALS

1dvanced materialsweight reduction 1luminum 0lasticSandwich structure

Functional area of the componentbased on strength5per5unit massfatigue limit

chemical 0rotective and cost

/anufacturing engineers and designers suggests the material dependingupon the fallowing parameters

:2//23 Y81


37/39

TOP TEN SAFETY CARS IN 0112

Mere&e%3Ben4 M C"!%%S!*et- Fe!t+re%# D+!" *ront !n& re!r %i&e3

mo+nte& !ir$!5%6 *ront !n& re!r e!&

!ir$!5%6 &ri7er !n& '!%%en5er e!&

re%tr!int% t!t re&+e ne8 in9+rie%

A+&i :;

S!*et- Fe!t+re%# Dri7er !n& '!%%en5er

e!&3re%tr!int


38/39

Cadillac _GM

4t can withstand roc>et and chemical attac>s 1 reinforced five inch steel plate runs under the car for protection inthe unli>ely event of a bomb being placed underneath and so on

/ORLD=S SAFEST CAR


39/39

safe drive with safe car

THANK YOU ALL

crash analysis 240509

Documents