Transcript Safety
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