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