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Occupant Motion and Injury Risk Analysis
In Rollover Accident
FHWA / NHTSA National Crash Analysis CenterThe George Washington University Virginia Campus
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NCACFHWA / NHTSA / National Crash Analysis CenterThe George Washington University
OUTLINE
Study Purpose
Modeling
Input Data and Parameters
Roof Crush
Vehicle motion
Results
Conclusion
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NCACFHWA / NHTSA / National Crash Analysis CenterThe George Washington University
Study Purpose
Study relationships to injury risk to belted occupants during
rollover.
Driver kinematics and physical measures are predicted by
MADYMO, an occupant modeling package, for a roll event (2.5
rolls).
Vehicle motion is pre-specified.
MADYMO calculates accelerations and loads on the dummy, so
that injury risk can be estimated.
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Parameters of the Study
Passenger or driver side leading roll
Shape of roof crush: No Deformation ( O ) (Baseline)
Roof Crush In ( M )
Roof Crush Out ( R)
Matchbox ( S )
A-pillar Crush ( T ) (FMVSS 216-like)
Extent of crush: No deformation at the first roof impact; 5 at the second
5 at the first roof impact; 10 at the second
Side window breaking time follows first impact
Upper interior compliant with FMVSS 201
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NCACFHWA / NHTSA / National Crash Analysis CenterThe George Washington University
Roof Crush Modes
M R
S T
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NCACFHWA / NHTSA / National Crash Analysis CenterThe George Washington University
Vehicle Motion
Desire to model as generically as possible
Need data on pre-roll and roll motion
Pre-roll calculated in HVE
Roll calculated by hand from rollover reconstructions
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NCACFHWA / NHTSA / National Crash Analysis CenterThe George Washington University
Accident Reconstruction: Pre-Roll
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NCACFHWA / NHTSA / National Crash Analysis CenterThe George Washington University
Accident Reconstruction: Roll
4 Rolls, Passenger Side Leading
NOTE: For the study, only 2.5 rolls are considered.
Airborne
Wheel Contact
CG Trajectory
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The George Washington University
Ballistic For Rollover Reconstruction
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Trajectory from Pre-Roll (HVE) and Reconstruction
Point of
Roll
HVE
Data Reconstruction Data
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The George Washington University
Simulation Matrix: 18 Cases; 2.5 rolls each
Roll 2
10 in
Roll 1
5 in
CRU
SH2
Roll 2
5 in
Roll 1
0 in
CRUSH1
TSRMOTSRMO
Driver Leading SidePassenger Leading Side
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Results
MADYMO allows relevant output from the dummy to
evaluate the injury risk.
Injury risk is calculated separately for each roll..
Output data is normalized to the baseline (no crush) or tothe Injury Assessment Reference Values (IARV).
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The George Washington University
Data Collected on the Dummy
Head Acceleration,
Velocity and
Displacement
Neck LoadsThorax Acceleration
and Displacement
Chest Deflection
Pelvis Accelerationand Displacement
Lap BeltLoads
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Matrix of Videos
Roll 2
10 in
Roll 1
5 in
CRUSH2
Roll 2
5 in
Roll 1
0 in
CRUSH1
TSRMOTSRMO
Driver Leading SidePassenger Leading Side
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Results
Occupant kinematics are greatly affected by vehicle pre-
roll and roll kinematics.
In passenger side leading rolls, there appears to be a higher
risk of partial ejection and ground contact.
In driver side leading rolls, head velocity relative to thevehicle interior is significant contact related injury risk
may be higher.
Primary restraint is maintained by the lap belt.
Injury metrics are being evaluated
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Limit of the study
No contact dummy/ground
Roll trajectory is not accurate enough to enable groundcontact at this stage.
The model is not validated: results can only be comparedto baseline test run with the same model.
Roof deformation is prescribed not predicted dynamically
in real-time
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The George Washington University
Outline
Validation of FMVSS 216 test using LS-DYNA
Validation of FMVSS 216 related research test with LS-
DYNA
Direct comparison of the standard and research tests to
find critical orientations for the roof performance
Conduct vehicle drop tests Validating model to all tests
Utilize model to investigate roof behavior and relationship
to injury risk
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
FMVSS 216 Update Research
FMVSS 216 is a relatively old standard and is approaching
revision.
Vehicles may now be optimized to the standard using
detailed computer modeling.
Change in rotation configuration of loading device is a key
investigative issue because: In reality vehicles, such as light trucks, can contact the ground at
higher roll and pitch angles.
Vehicle components (pillars, doors, roof, etc) in wider angle
contacts may reduce ability to crush and induce bending modes.
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
FMVSS 216 Test Specifications
216 Tests Original Updated ProtocolTest Type Static Static
Dimensions of Loading Device (in) 30*72 30*72
Roll Angle (deg) 25 45
Pitch Angle (deg) 5 10
Velocity of Loading Device (in/sec) 0.5 0.5Maximum Amount of Load (N) 60,000 60,000
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The George Washington University
NHTSA 216 Research Tests
25-5 config before and after test 45-10 config before and after test
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The George Washington University
NHTSA Tests
FMVSS 216 test w/
25o roll & 5o pitch
FMVSS 216 test w/
45o roll & 10o pitch
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NHTSA Test Results
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The George Washington University
Replicate Research Tests by finite element modeling
Finite element model of S-10 pick up truck
Finite element model is created to simulate roof crush for
any scenario of impact.
Complex finite element calculations can be solved very
fast by running on super computers.
FMVSS 216 tests are used as validation points.
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Finite Element Modeling of S-10 Pickup Truck
A 4x4 Matrix can be created to describe
the effect of rotation change:
W/O Windshield
W/ Windshield
45-1025-5Test Type
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Finite Element Modeling of the S-10 Pickup Truck
216 test with 25-5configuration.
Without glass
Simulation period: 0.37 sec
Contact Velocity: 0.5
in/sec (12.7 m/sec)
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Finite Element Modeling of the S-10 Pickup Truck
216 test with 45-10
configuration
Without glass
Simulation period: 0.37 sec
Contact Velocity: 0.5 in/sec(12.7 m/sec)
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Finite Element Modeling of the S-10 Pickup Truck
216 test with 45-10
configuration
With glass
Simulation period: 0.37 sec
Contact Velocity: 0.5 in/sec(12.7 m/sec)
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
Multiple drop tests of Chevrolet S-10 on roof structure Simulate roof crush specifications of FMVSS 216 in dynamic drop
Monitor impact forces with load cell plate
Monitor timing, extent, and rate of intrusion relative to occupant
compartment
Monitor vehicle accelerations
Investigate contributions of roof structure and window glass
Instrumentation on S-10 focused on model validation Accelerometers for vehicle structural validation and effect on occupant
interaction
Load cell plate for vehicle structural validation String pots for structural validation and intrusion measurements
NCAC Research Tests for Roof Crush
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NCACFHWA / NHTSA / National Crash Analysis Center
The George Washington University
NCAC Research Tests for Roof Crush
25oFront View 5o Side View
Drop Height = 6 (152mm)
String Pots
Roof Intrusion
Accelerometers
(Linear)
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The George Washington University
10 (254 mm)
72 (1829 mm)
30(762mm)
Point of first contact with roof
(approximate corner of A-pillar)
15(127mm)
12 Load Cells
10 x 10
NCAC Research Tests for Roof Crush
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The George Washington University
Simulate drop test:
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The George Washington University
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The George Washington University
NCAC Drop Test
1st Impact
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The George Washington University
NCAC Drop Test - 1st Impact
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The George Washington University
NCAC Drop Test - 1st Impact
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The George Washington University
NCAC Drop Test
2nd Impact
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The George Washington University
NCAC Drop Test - 1st Impact
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The George Washington University
NCAC Drop Test Results
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The George Washington University
NCAC Drop Test Results
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The George Washington University
NCAC Drop Test Results
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The George Washington University
Utilize Various Test Data in Occupant Model
Roll angles modified so that impact occurs at 25 or 45
degrees of roll
Pitch angles modified so that impact occurs at 5 or 10degrees of pitch
The crush direction is on the normal to the impact (25/5
deg or 45/10 deg) to correspond with test data loading
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The George Washington University
Matrix of Videos
45 / 10
deg
25 / 5
degRoll and
Pitch
Angles
at
Impact
FOIL
Drop Test5 100 50 0
Crush extend at first and second
impactPassenger Side
Leading Rolloverwith A-pillar
crush (T mode)
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The George Washington University
Next Step Toward Evaluation:
Validate computer model to four tests
Investigate influence of the windshield
Run simulations for more additional configurations withdifferent angles
Use different materials for vehicle components (pillars,headers, etc) in order to study effect on roof crush
resistance Integrate detailed roof performance with occupant model
for full injury risk assessment.
Utilize computer models to assess countermeasures andbenefits