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
FRONTAL OFFSET
REAR IMPACT
US IIHS
ECE R32
AU/EU/JP/US NCAP
FMVSS 208
FRONT SEAT
REAR SEAT
US NCAP
FMVSS 214
ROOF CRUSH
AU/EU/JP NCAP
FMVSS 301
SIDE POLE IMPACT
SIDE IMPACT
IIHS/JP/AU/EU NCAP
ECE R95
HEAD IMPACT
EU NCAP
PEDESTRIAN IMPACT
ADULT
HEAD
LEG
FREE
MOTION
HEAD FORM
FMVSS 216
Off-set Frontal Impact
Parameter
ECE-94 Offset Frontal Impact
Regulation
Vehicle
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
EEVC
ODB
56 kph
Test Weight = Kerb Weight + Dummies Weight
2 Hybrid-III Belted Dummies
Thorax Compression Criteria
< 50 mm
Viscous Criteria (Thorax)
< 1.0 m/s
Tibia Compression Force
< 8.0 kN
Tibia Index
Sliding Knee joint movement
Femur Force
Speed = 56 (-0, +1) kph
40% Offset deformable barrier impact
No locking of Door lock systems
Door openability
Dummy release and removal
Fuel Leakage
< 1.3
< 15 mm
Off-set Frontal Impact
Assessments
Deformed Shape
1.
2.
2.
3.
4.
5.
6.
7.
Available Crush space
Steering Column Vertical and Rearward Intrusions
Dash and Toe-board intrusions
Deceleration pulse and Total dynamic crush
Major Load paths
Energy absorption for key components
Fuel Tank damage
Front Door aperture deformation
Off-set Frontal Impact
Baseline Intrusions
Toe Pan Intrusions
Brake Booster Location
Toe Board Locations
Hinge Pillar
Steering Column Intrusions
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
Counter Measures to reduce Dash intrusion
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
Side Impact
ECE-95 Side Impact Regulation
Target
Vehicle
50 kph (+/- 1)
Centerline at
R-point
59”
2094 lbs
EEVC Moving Deformable Barrier
Front
Test Weight = Kerb Weight + 1 Dummy Weight
17.3”
9.8”
9.8”
Parameter
Unit
Target
-
< 1000
Rib deflection
mm
< 42
Viscous Criteria (Thorax)
m/s
< 1.0
Pubic Symphysis Force
kN
</= 6
Abdomen Force
kN
< 2.5
HPC (HIC) (If Head contacts)
Door openability
Dummy release / removal
Fuel leakage
19.7”
Barrier Side View
Foam material
Internal components
Side Impact
Analysis Setup Details
R Plane : Middle of Barrier
50kph
300mm
 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
Side Impact
Vehicle Global Deformation
B/line
H -Point
 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)
Collapse of Sill Section at B
Post Flange End
Side Impact
Intrusion Measurement on B-post
Top
B-POST Roof
Rail Level
Beltline
H point
B-POST Belt
Line Level
Base
Front View 105ms
(Undeformed in Blue)
Parameter
B-Post H-Point
Level
B-Post Base
Measurement Points
Intrusion (mm)
B-POST Belt Line Intrusion
-----
B-POST H-point Level Intrusion
-----
B-POST Base Intrusion
-----
B-POST Top Intrusion
-----
Roof Crush
1829 mm
FMVSS 216 Roof Crush Regulation
762 mm
Force
Force
Test Device
Front View
Side View
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.
Roof Crush
5 deg
25 deg
254 mm (Forward Edge of the Test
Device to Forward Most Point of Roof)
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
Front View
Left View
B-Pillar
 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
Criteria Measured
Body Form
Impactor
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
LEG
ADULT
HEAD
Injury Criteria
Pedestrian Protection
Initial Velocity





Lower Leg Consisted of TIBIA and FEMUR Joined at Knee
Initial Velocity Assigned to Leg Form and Set as Free Flight
Vehicle Front end Model was Constrained at Rear
Leg Impact was Done with 42 KMPH Initial Velocity
TIBIA Acceleration, Knee Shear and Knee Bending Calculated for
Each Case
 Foam 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
Impact Locations
A-Pillar Lower
A-Pillar Mid
HEAD IMPACT
A-Pillar Joint
Windshield Header
FREE MOTION HEAD
FORM
Visor Attachment
Roof Side Rail between A/B Pillars
Velocity = 15 mph
B-Piller Lower
B-Pillar Mid
B-Pillar Mid
FMVSS 201U
B-Pillar Joint
Roof Side Rail between B/C Pillars
Criteria Measured
C-Pillar Joint
Rear Header
HIC
< 10000
Upper Roof
Moon roof Frame
Head Impact
Head Impact Simulation
Head Impact
Hit on Roof Above C-Pillar (Roofc)
Hit on Sun Roof Guide Rail
Hit on Roof Above B-pillar (Roofb)
Hit on Grab Handle
Head Impact
Roof Bow
Honeycomb
Countermeasure
Roof Bow
C-Pillar
C-Pillar
Headliner
Design Issues:
 Does Not Meet HIC Requirement at
Various Location
 Space Between Headliner and Roof Not
Sufficient for Any Countermeasure
Headliner
Design Solutions:
 Headliner Contour Changed to Create
Space Between Headliner and Roof
Bow
 Honeycomb Countermeasure Added to
Meet HIC Requirement
Head Impact
Example: Counter Measure
Honeycomb Piece as
Counter Measure
 Several Honeycomb
Density Evaluated
 Several Thickness
Evaluated
 Other Counter
Measures Evaluated
 Cost Effective
Solution Provided
Frontal Impact
Passenger
Compartment
Barrier
Engine
Compartment
Impact
Speed
Body Rail
Front
Clearance
Dash
Clearance
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, hence
Resulting deceleration is quite large 30-80 G
Frontal Impact
Yield Stress σy
Stress σ
Failure Stress σf
Rail Load
Absorbed
Impact
Energy
Failure
Strain εf
Strain ε
Rail Crush
Material Stress-Strain Curve
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
Front
Clearance
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