Vehicle Safety. Vehicle Safety Requirements Safety Requirements Side Impact Frontal Impact – Rigid Barrier Frontal Offset Impact Rear impact Pedestrian.

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    18-Dec-2015

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  • Slide 1
  • Vehicle Safety
  • Slide 2
  • 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
  • Slide 3
  • Vehicle Safety Loadcases FULL-WIDTH FRONTAL AU/EU/JP/US NCAP FMVSS 208 FRONTAL OFFSET AU/EU/JP NCAP US IIHS REAR IMPACT ECE R32 FMVSS 301 SIDE IMPACT IIHS/JP/AU/EU NCAP US NCAP FRONT SEAT REAR SEAT FMVSS 214 ECE R95 EU NCAP SIDE POLE IMPACT FMVSS 216 ROOF CRUSH HEAD IMPACT FREE MOTION HEAD FORM UPPE R LEG LEG CHILD HEAD ADULT HEAD PEDESTRIAN IMPACT
  • Slide 4
  • Off-set Frontal Impact ParameterTarget 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 EEVC ODB 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 Regulation
  • Slide 5
  • Off-set Frontal Impact Assessments 1. 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
  • Slide 6
  • 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
  • Slide 7
  • 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
  • Slide 8
  • Side Impact 17.3 9.8 19.7 Barrier Side View Foam material 9.8 Front 50 kph (+/- 1) 2094 lbs Test Weight = Kerb Weight + 1 Dummy Weight EEVC Moving Deformable Barrier Target Vehicle 59 Centerline at R-point ParameterUnitTarget HPC (HIC) (If Head contacts)-< 1000 Rib deflectionmm< 42 Viscous Criteria (Thorax)m/s< 1.0 Pubic Symphysis ForcekN
  • Slide 9
  • 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
  • Slide 10
  • 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)
  • Slide 11
  • Side Impact ParameterIntrusion (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 Belt Line 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)
  • Slide 12
  • 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
  • Slide 13
  • 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
  • Slide 14
  • 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
  • Slide 15
  • Pedestrian Protection Euro-NCAP Pedestrian Impact Criteria Measured UPPER LEG LEG CHILD HEAD ADULT HEAD Body Form Impactor Injury CriteriaLimit LegformKnee Bending Angle15 deg LegformKnee Shear Displacement 6 mm LegformUpper Tibia Acceleration 150 g Upper LegformSum of Impact Forces 5 kN Upper LegformBending moment300 N-m Child HeadformHead Injury Criteria1000 Adult HeadformHead Injury Criteria1000
  • Slide 16
  • 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
  • Slide 17
  • 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
  • Slide 18
  • Head Impact FMVSS 201U - Interior Head Impact Criteria Measured HEAD IMPACT FMVSS 201U FREE MOTION HEAD FORM Velocity = 15 mph HIC < 10000 Impact Locations A-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 Joint Roof Side Rail between B/C Pillars C-Pillar Joint Rear Header Upper Roof Moon roof Frame
  • Slide 19
  • Head Impact Head Impact Simulation
  • Slide 20
  • 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
  • Slide 21
  • Head Impact Design Issues: Does Not Meet HIC Requirement at Various Location Space 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 Bow C-Pillar Headliner Honeycomb Countermeasure
  • Slide 22
  • 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
  • Slide 23
  • Frontal Impact Body Rail Engine Compartment Passenger Compartment Barrier Impact Speed Front Clearance Dash Clearance
  • Slide 24
  • Frontal Impact Initial Kinetic Energy = 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
  • Slide 25
  • Frontal Impact Strain Stress Yield Stress y Failure Stress f Failure Strain f Material Stress-Strain Curve Rail Crush Rail Load Rail Load = * A Rail Crush = * L Where A is the cross-sectional area of the rail L is the length of the rail Front Clearance Absorbed Impact Energy
  • Slide 26
  • 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

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