An Assessment of the Relations hip Between Frontal Impact ...
Vehicle Safety. Vehicle Safety Requirements Safety Requirements Side Impact Frontal Impact – Rigid...
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Transcript of Vehicle Safety. Vehicle Safety Requirements Safety Requirements Side Impact Frontal Impact – Rigid...
Vehicle Safety
Vehicle Safety Requirements
Safety Requirements
Side Impact
Frontal Impact – Rigid Barrier
Frontal Offset Impact
Rear impact
Pedestrian Protection
Roof Crush
Seat subsystem
Interior Head Impact
Low Speed Bumper Impact
Vehicle Safety Loadcases
FULL-WIDTH FRONTAL
AU/EU/JP/US NCAPFMVSS 208
FRONTAL OFFSET
AU/EU/JP NCAP
US IIHSREAR IMPACT
ECE R32
FMVSS 301
SIDE IMPACT
IIHS/JP/AU/EU NCAPUS NCAP
FRONT SEAT
REAR SEAT
FMVSS 214 ECE R95 EU NCAP
SIDE POLE IMPACT
FMVSS 216
ROOF CRUSH HEAD IMPACT
FREE MOTION
HEAD FORM
UPPER L
EG
LE
G
CHILD
HEADADULT HEAD
PEDESTRIAN IMPACT
Off-set Frontal Impact
Parameter Target
HPC < 1000
Head Resultant Accel. < 80 G
Residual Steering Column X-Displacement
< 100 mm
Residual Steering Column Z-Displacement < 80 mm
Neck Injury Criteria
Thorax Compression Criteria < 50 mm
Viscous Criteria (Thorax) < 1.0 m/s
Tibia Compression Force < 8.0 kN
Tibia Index < 1.3
Sliding Knee joint movement < 15 mm
Femur Force
No locking of Door lock systems
Door openability
Dummy release and removal
Fuel Leakage
EEVCODB
56 kph
Vehicle
2 Hybrid-III Belted Dummies
Test Weight = Kerb Weight + Dummies Weight
Speed = 56 (-0, +1) kph
40% Offset deformable barrier impact
ECE-94 Offset Frontal Impact ECE-94 Offset Frontal Impact Regulation Regulation
Off-set Frontal Impact
Assessments1. Available Crush space
2. Steering Column Vertical and Rearward Intrusions
2. Dash and Toe-board intrusions
3. Deceleration pulse and Total dynamic crush
4. Major Load paths
5. Energy absorption for key components
6. Fuel Tank damage
7. Front Door aperture deformation
Deformed Shape Deformed Shape
Off-set Frontal Impact
Baseline Intrusions
Steering Column Intrusions
Toe Pan Intrusions
Brake Booster Location
Toe Board Locations
Hinge Pillar
Steering Column Intrusions Measured at the Wheel Hub Location
Dash Board Intrusions were Higher and Needs Improvement Steering Column Intrusions Are Meeting the Requirements
Off-set Frontal Impact
The Material Grade and Thickness of these components were upgraded to increase the stiffness
Dash and Steering Column intrusions were significantly improved in final version
Peak crash pulse was also within the target level
Counter Measures to reduce Dash intrusion
Side Impact
17.3”
9.8”
19.7”
Barrier Side ViewFoam material
9.8”
Front
50 kph (+/- 1)
2094 lbs
Test Weight = Kerb Weight + 1 Dummy Weight
EEVC Moving Deformable Barrier
TargetVehicle
59”Centerline atR-point
Parameter Unit Target
HPC (HIC) (If Head contacts) - < 1000
Rib deflection mm < 42
Viscous Criteria (Thorax) m/s < 1.0
Pubic Symphysis Force kN </= 6
Abdomen Force kN < 2.5
Door openability
Dummy release / removal
Fuel leakage
Internal components
ECE-95 Side Impact Regulation ECE-95 Side Impact Regulation
Side Impact
Center of the Barrier Oriented to R Point Plane of Dummy
Unladen Ground Line Data was Used As Ground
Contact Defined Between Barrier and Occupant Side Vehicle Parts
Distance Between Lower Edge of Honey Comb Barrier to Floor was 300mm
R Plane : Middle of Barrier
50kph
Analysis Setup Details
300mm
Side Impact
Vehicle Global Deformation
Collapse of Sill Section at B Post Flange End
H -Point
B/line
Overall Vehicle Deformation Looks Good B-pillar Intrusion Measured at Belt Line Level Is
Lesser Than Intrusion Measured at H Point Level. Overall Deformed Shape of the Pillar Looks Good
Sill Section Below the Slide Door Lower Edge Buckles Close to B-pillar Due to Weaker Sill Section at This Location
B Post Lateral Deformation (Undeformed in Blue)
Side Impact
Parameter Intrusion (mm)
B-POST Belt Line Intrusion -----
B-POST H-point Level Intrusion -----
B-POST Base Intrusion -----
B-POST Top Intrusion -----Measurement Points
B-POST Roof Rail Level
B-POST BeltLine Level
B-Post H-Point Level B-Post Base
Intrusion Measurement on B-post
Top
Beltline
H point
Base
Front View 105ms(Undeformed in Blue)
Roof Crush
Force
Front View
762 mm
Side View
1829 mm
Force
Test Device
Rigid Horizontal Surface
Meet following roof strength criteria:This standard establishes strength requirements for passenger compartment roof.Force applied is 1.5 times unloaded vehicle weight in kgs. times 9.8, but should not exceed 22,240 N for passenger cars.Lower surface of test device must not move more than 127 mm.
FMVSS 216 Roof Crush Regulation FMVSS 216 Roof Crush Regulation
Roof Crush
1829mm 762mm
254 mm (Forward Edge of the Test Device to Forward Most Point of Roof)
25 deg
5 deg
SPC Constraints
Boundary Conditions• Rigid Flat Surface Was Oriented at the Front Driver
Side Roof As Shown in the Above Pictures• Prescribed Velocity Was Applied to the Rigid Flat
Surface and the Run Was Done Till 125mm Roof Crush
• BIW Was Fixed at the Sill Area (for All DoFs) Using Single Point Constraints
Acceptance Criteria
• Force Equivalent to 1.5 Times the Unloaded Vehicle Weight or 22,240N, Whichever Is Less Should Be Applied on the Vehicle Roof Structure Using the Rigid Flat Test Device As Per FMVSS 216 Test Setup
• The Lower Surface of the Test Device Must Not Move More Than 125mm for This Load
Roof Crush
B-Pillar
Front View Left View
The Model Is Meeting the Roof Crush Resistance As Required by FMVSS 216 B-pillar Buckles at the Belt Line Location
Pedestrian Protection
Euro-NCAP Pedestrian Impact Euro-NCAP Pedestrian Impact Criteria Measured
UPPER LEG
LE
G
CHILD
HEAD
ADULT HEAD
Body Form Impactor
Injury Criteria Limit
Legform Knee Bending Angle 15 deg
Legform Knee Shear Displacement
6 mm
Legform Upper Tibia Acceleration
150 g
Upper Legform Sum of Impact Forces
5 kN
Upper Legform Bending moment 300 N-m
Child Headform Head Injury Criteria 1000
Adult Headform Head Injury Criteria 1000
Pedestrian Protection
Initial Velocity
Lower Leg Consisted of TIBIA and FEMUR Joined at KneeInitial Velocity Assigned to Leg Form and Set as Free FlightVehicle Front end Model was Constrained at RearLeg Impact was Done with 42 KMPH Initial VelocityTIBIA Acceleration, Knee Shear and Knee Bending Calculated for
Each CaseFoam and Facia Modified During the Iterative Process
Pedestrian Protection
Bumper System Met the Knee Injury Criteria as Required by EEVC
Force on Bumper Sensor was Maximum and Consistent Irrespective of Position of Impact
Equivalent Impactors Developed for Pedestrian Dummies
Head Impact
FMVSS 201U - Interior Head Impact FMVSS 201U - Interior Head Impact
Criteria Measured
HEAD IMPACT
FMVSS 201U
FREE MOTION HEAD FORM
Velocity = 15 mph
HIC < 10000
Impact LocationsA-Pillar Lower
A-Pillar Mid
A-Pillar Joint
Windshield Header
Visor Attachment
Roof Side Rail between A/B Pillars
B-Piller Lower
B-Pillar Mid
B-Pillar Mid
B-Pillar Joint
Roof Side Rail between B/C Pillars
C-Pillar Joint
Rear Header
Upper Roof
Moon roof Frame
Head Impact
Head Impact Simulation
Head Impact
Hit on Roof Above C-Pillar (Roofc) Hit on Roof Above B-pillar (Roofb)
Hit on Sun Roof Guide Rail Hit on Grab Handle
Head Impact
Design Issues:Does Not Meet HIC Requirement at
Various LocationSpace Between Headliner and Roof Not
Sufficient for Any Countermeasure
Design Solutions:Headliner Contour Changed to Create
Space Between Headliner and Roof Bow
Honeycomb Countermeasure Added to Meet HIC Requirement
Roof BowRoof Bow
C-Pillar C-Pillar
HeadlinerHeadliner
Honeycomb Countermeasure
Head Impact
Example: Counter Measure
Honeycomb Piece asCounter Measure
Several Honeycomb Density Evaluated
Several Thickness Evaluated
Other Counter Measures Evaluated
Cost Effective Solution Provided
Frontal Impact
Body Rail
EngineCompartment
PassengerCompartment
Barrier
ImpactSpeed
FrontClearance
DashClearance
Frontal Impact
Initial Kinetic Energy = ½ M V 2
Final Kinetic Energy = 0 as vehicle comes to a stop
Initial Kinetic Energy is absorbed by deforming body rail
Collision impact duration is less than 100 ms, henceResulting deceleration is quite large 30-80 G
Frontal Impact
Strain ε
Str
ess
σ
Yield Stress σy
Failure Stress σf
Failure
Strain εf
Material Stress-Strain Curve
Rail Crush
Rai
l L
oad
Rail Load = σ* A
Rail Crush = ε* L
Where A is the cross-sectional area of the rail L is the length of the rail
FrontClearance
AbsorbedImpactEnergy
Frontal Impact
Assignment:
Assume impact speed of 50 kph
Pick any material for the rail and find stress/strain curve
Assume length of the rail based on vehicle dimensions
Calculate required rail section area and design a section
Show that initial K.E. = energy absorbed by the rail