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VEHICLECRASHWORTHINESSANDOCCUPANTPROTECTION
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MotorVehicleSafet
TheAutomobile
Structure
Materials
Crashworthiness
CrashworthinessGoals
CrashworthinessRequirements
AchievingCrashworthiness
ras wort nesstests
CrashworthinessModelRequirements
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Contents
The first motor vehicle fatalit occurred in 1889 in New
York City. An early period of safety from the turn of the century to
1935 period of genesis, growth, and development to
understanding the extremely complex process of vehicle
collisions.
The second period from 1936 to 1965 intermediate safety
period with crash avoidance devices.
The third period starts in 1966
the creation of the National
Highway Traffic Safety Administration (NHTSA).
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Currentcarbod structuresandli httrucks
body
over
frame
structure
unitbodystructure(includingspaceframe)
e c e o y External to minimize drag
accommodate its occupants
Vehicle body with the suspension to minimize road
Vehiclestructuretomaintainitsintegrityandprovideadequateprotectioninsurvivablecrashes
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BodyonFrameBodyinwhiteofaUnibody
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The ma orit of mass roduced vehicle bodies over the
last six decades were manufactured from stampedsteel components.
Until the 1920s, automakers built vehicle bodies from
a composite of wood panels joined with steel brackets. As metallurgists improved the formability of sheet steel
and toolmakers built durable dies capable of stamping
joining large body shells.
.
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Crashworthinessmeasure of the abilit of a structure
and any of its components to protect the occupants insurvivable crashes. (aerospace industry)
Crashworthiness connotes a measure of the vehicles
structural ability to plastically deform and yet maintaina su c en surv va space or s occupan s n cras es
involving reasonable deceleration loads.
additional protection to reduce severe injuries and
fatalities.
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absorb part of the crash kinetic energy.
compartment and simultaneously control the crash
deceleration ulse.
Accident reconstruction and analysis of vehicle crashes
rovide information re ardin the safet erformance.
Currently, vehicle crashworthiness is evaluated in four
distinct modes: frontal side rear and rollover crashes.
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properride
and
handling.
thatgiverisetoharshness.
Accommo ate orarangeo occupants zes,
ages,andcrashspeedsforbothgenders.
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Characteristics:
Deformable,
yet
stiff,
front
structure
with
crumple
zonestoabsorbthecrashkineticenergy.
.
Properlydesignedsidestructuresanddoorsto
minimizeintrusion.
Strongroofstructureforrolloverprotection.
Properlydesignedrestraintsystemsthatworkinharmon withthevehiclestructure.
Accommodatevarious
chassis
designs
for
different
powertrainlocationsanddriveconfigurations
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Uni ueworkofautomotivestructural
crashworthinessengineer
:
must meet all service load requirement and it mustdeform plastically in a short period of time(milliseconds) to absorb the crash energy in a
controllable manner.
must be light and be economically massproduced.
The structural stiffness must be tuned for ride and
an ing, NVH an must e compati e wit ot ervehicles on the road, so it is not too soft or tooa ressive.
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packagingthe
occupants
for decelerations
transmittedtotheoccupantsaremanageablebytheinteriorrestraintstofallwithintherangeof
human
tolerance.
u g y g reduceoccupantharm.
,combination
of
crash
avoidance
and
crashworthinessmeasures.
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in crashworthiness simulations, vehicle.
Three categories of tests:
omponen es s
Sledtests
Fullscale
barrier
impacts
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Dynamic
and/or
quasi
static
response
to
loading
.
Crucialinidentifying
Energyabsorptioncapacity
developmentofmathematicalmodelsand
.
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Vehicle
buck
passenger
compartment
Ant ropomorp ictest evicesorca avers
driversor
passenger.
Dynamicloadvehicledecelerationtimepulse
Primar ob ective toevaluaterestraints
Sensorsondummy,highspeedphotography
.
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Fullscalebarriertest:
Collision
of
aguided
vehicle,
propelled
into
abarrieratapredeterminedinitialvelocityand
.
Abarriertestusesacompletevehicle.
. Frontalimpactwithbarrierzero, 30
Unrestraineddummiesinthedriverandrightfront
passenger NCAP higherspeedimpactwithrestrained
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CrashworthinessModelsContentsRequirements
Accurac themodelshouldbeableto ieldreasonabl
accurate
predictions
of
the
essential
features
being
sought Speed themodelshouldbeexecutablewithareasonable
turnaroundtime,nottoexceed12hoursregardlessofits
size,toallowforiterationsandparameterstudies.
notyieldlargemodelresponses.
Developmenttime themodelcouldbebuiltina
reasonablyshort
period
of
time,
not
to
exceed
two
weeks