Impact of the new regulation for Child restraint systems on the crash simulation


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Impact of the new regulation for Child restraint systems on the crash simulation

  1. 1. Impact of the new regulation for Childrestraint systems on the crashsimulationSylvaine PormentéFrançois Renaudin23rd April 2013
  2. 2. 2Corporate informationDorel groupJuvenile brands portfolioOverview of I-Size regulationNew regulation4 Key pointsImpact on simulationSled bench studyDummy evaluationConclusionContents
  3. 3. 3• Celebrating 50 years of innovation• Headquarters in Montreal, Canada• Approximately 5000 employees worldwide• Operates in 22 countries• $2.4 billion in sales, Sells to over 100countries• World’s largest juvenile products company• U.S. market leader in recreational bikes• #2 U.S. brand in RTA (ready to assemble)home furnitureDorel Industries Inc.key brands
  4. 4. Strong Brand portfolio
  5. 5. I-Size regulation• I-Size is a new regulation– Increase the safety level for children in cars– Improve ease of use for parents :• Promote Isofix which facilitates child seat installation• Force CRS manufacturer to adapte to child anthropometry• Increase compatibility between child seat and cars• Will be enforced by July 2013• For a while, the current standard ECER44/04 will remain in effect for all beltinstalled child seats• I-Size Phase 2 in progress for– Booster seats– Belted restraint products5
  6. 6. 100 % Isofix– 2 Anchorages and an anti rotation deviceTop Tether or support leg– No use of the adult safety belt– Only harness to restraint children (integral system)– External dimensions for compatibility with vehicle : Envelope for Rearwardfacing or front facing position– Weight: MCRS + largest child < 33 kg,Key points : Isofix6
  7. 7. Key points : Dynamic testSide impact• Specific pulse• Intruding door with controlled door intrusionvelocity• Kinematics criteria:– No head contact with door panel– shall not exceeded a vertical plan ontop of a door• Injury criteriaNew bench• New cushion (foam, geometry)7
  8. 8. Key points : Crash Safety– New Q dummies family will replace old P-dummies– Additional criteria compared to R44– Abdominal loading not available for phase 1 of i-Size regulation– Rearward facing mandatory up to 15 monthsTo be reviewed within 3 years following entry into force of this regulation /Frontal impactSide impact5,2tt1212 adttt1)tt(HPC21  8
  9. 9. Key points : new classification• Classification of CRS– Classification by stature– CRS dimensions: in accordance with internal and external envelopes9
  10. 10. Integration in simulation of the new I-Size constraintsto be more predictive to validate CRS designin terms of integrity but also in terms of performanceNeed to have robust, reliable and validated tools for the I-size context Calibration and validation of the environment of the CRS– Foam of the new bench seat– Side impact door padding. Validation of the representativity of the Q dummies– the global and local behaviour– Need to reduce boundaries conditions influenceImpact on crash simulation10Softwares environnementAltair HyperWorks 11,0dummy radioss format
  11. 11. 0,0500,01000,01500,02000,02500,00,0 10,0 20,0 30,0 40,0Force(N)Displacement (mm)testsimulation loadingEnvironment : Bench foam modeling2 / Dynamic Correlation– Simple tests performed to represent CRS dynamic loading on the bench Improved law1 / Static Correlation– Static foam law (force/displacement)– Compression + hysteresisMass (kg) error %25.6 1,730.1 -0,833.1 3,1 11
  12. 12. 1 / Dummy test (Q3)– With a standard installation on rigid seat– Head data (acceleration and displacement): the simulation shows aconservative result against the testThe validation requirements (certification) of these models seems notcover the loadcase observed in I-Size use.Need to enhance the certification test matrix in collaboration withAltair for the numerical aspects (through a Competitive ClusterProETech)Dummy Evaluation2 / Specifics tests– Neck and Head evaluation in dynamic condition– Strong harnessed dummy on rigid seat– Dummy on rigid seat with a rigid shield12
  13. 13. Head formNeckPendulumQ3 neck/head segmentInput data :– frontal and lateral impact– 4 m/s < velocity < 8 ms/sResults• Good correlation for low speed• For 8m/s (value similar to frontal impact head velocity)– Moment is overestimated (17%)– 20% difference for HIC and neck force data– The return motion of head is earlier in simulationDorel and Altair enhanced the material laws to improve the response ofhead / neckDOE on material law based on neck certification testresponses : head rotation and neck moment13Certification tests do not cover the range of velocities observed in testsconducted by Dorel.
  14. 14. Q3 neck/head segmentInitial Law Improved lawBetter behaviorReduce gap– Neck Moment– Head Acceleration– Head displacementReduce time shifting– back and-forth motionhead14
  15. 15. Harnessed Q3 on rigid seatInput data :Frontal Impact with I-size pulse - Steel rigid seat - Harness with hight pretension3 steps : pretension / kinematic relaxation / descelerationResults- Strong Abdominal deformationPossible causes– Interaction between dummy and Harness– Stiffness forThoraxAbdomenPelvis– Initial dummy positioning1540 ms 90 ms 130 msNew test with rigid shield instead of harness
  16. 16.  Futur work will focus onabdomen and thorax stiffness investigationStrain rate influenceQ3 on rigid seat with rigid shield– Not correlated kinematic– Strong crushing area (abdomen) The lack of abdomen stiffness disrupts the results Not acceptable dummy behavior40 ms 55 ms16
  17. 17. Conclusion Altair Hyperworks tools are integrated in the development ofour CRS products to validate design in terms of integrity butalso in terms of performance Working with performance criteria implies to know all theelements in interaction with the CRS. The Need for improved Q dummy modeling Collaboration with Altair and Humanetics to obtain a robust Qdummies family adapted to the I-size regulationFor both configuration: frontal and side impact17
  18. 18. ACKNOWLEDGEMENTSCurrent study was supported byFrench Ministry of Industry and Pays de laLoire Regional CouncilThrough the ProETech Competitive ClusterIn collaboration with Altair18