Euro NCAP Whiplash Rating - Toyota Position & Proposal. May 2011

Transcription

1 Euro NCAP Whiplash Rating - Toyota Position & Proposal May

2 Content Background and Priority J-NCAP Extended Review Overall Conclusion 2

3 Schedule 2011 February June Folksam Chalmers TNO ADAC BASt (15.03) TRL (11.05) B. Fildes (ESV) Euro NCAP (TBC) 3

4 Background: Past TOYOTA presentation 4

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9 Marginal rating Good real-life effectiveness 9

10 1 st Priority Improvement Remove HRCT, T1Gmax, RV No relevance in real life safety Design restrictive 10

11 J-NCAP 11

12 J-NCAP criteria and thresholds are based on the work of Ono et al. Evaluation Criteria for the Reduction of Minor Neck Injuries during Rear-end Impacts Based on Human Volunteer Experiments and Accident Reconstruction Using Human FE Model Simulations 12 Koshiro Ono1), Susumu Ejima1), Kunio Yamazaki1), Fusako Sato1), Jonas Aditya Pramudita2), Koji Kaneoka3), and Sadayuki Ujihashi 2) 1) Japan Automobile Research Institute, 2) Tokyo Institute of Technology, Japan, 3) Waseda University, Japan

13 J-NCAP criteria and point generation New Car Assessment Japan 2010, page

14 J-NCAP thresholds: sliding scale between 5% and 95% WAD 2+ risk 5% WAD2+ risk 95% WAD2+ risk JAPAN NEW CAR ASSESSMENT PROGRAM FOR MINOR NECK INJURY PROTECTION IN REAR-END COLLISIONS Takahiro IKARI, Kenichi KAITO National Agency for Automotive Safety and Victims Aid (NASVA), JAPAN Taichi NAKAJIMA, Kunio YAMAZAKI, Koshiro ONO Japan Automobile Research Institute (JARI), JAPAN ESV Paper Number

15 Extended Criteria Review 15

16 Extended Criteria Review (1) gtr7 (2) Biomechanics of Whiplash (3) Real life data analysis Today s Agenda (4) Criteria proposal (5) Implications (6) Threshold proposal (7) Implications (8) New rating scheme For a later day (9) Evaluation of real life relevance 16

17 Whiplash Regulation, Assessment started under making ~ GTR GTR-Phase1 GTR-Phase2 (Step1)? GTR-Phase2 (Step2)? Assessment Reguration JP EU US JP EU US Korea IIHS Folksam Thatcham E-NCAP J-NCAP FMVSS202a(FR) K-NCAP (RR) ECE17-10? ECE17-10? New FMVSS202a? China C-NCAP? 17

18 Purpose and situation of Head Restraint GTR making Solving the following problem of the Whiplash evaluation of the current state is necessary. Governments and the industry are jointly working on it within WP29/GRSP.. 1.Evaluation by Injury Criteria Japan proposed the assessment based on Ono 2009 (completed). An original research that uses PMHS is being conducted in the United States (until end of 2011). Injury Criteria of GTR7 is to be considered by a joint research of JARI(Ono) and NHTSA. Japan proposal NHTSA study 18

19 2.Guarantee of Repeatability Reproducibility The Cause of variability is studied in each country. Improvement of BioRID Ⅱ calibration is studied by Humanetics Co.. Reduction of dummy setting tolerance (Completed at GTR7-Phase1). When establishing the regulation, improvement of Repeatability Reproducibility is requested and necessary. PDB study Humanetics Co. Calibration study Dummy set proposal 19 (Fixed at GTR7-Phase1. )

20 3. Test method to reflect the real world Seat back angle to be set (and tested) at design angle is considered in each country. Test speed appropriate for permanent injury reduction is considered in each country. Large stature (AM95-three dimensional manikin) is considered by the Netherlands &TNO. Small design torso angle Dummy setting study Test speed for injury reduction study High height person study 20

22 Biomechanics of Whiplash injuries Injury criteria review None of the proposed injury criteria were found to have a definite biomechanical basis and their validity in predicting the risk needs to be established. None of the criteria can be recommended on a strictly biomechanical basis. Considered were main injury criteria proposed in literature: Nij, Nkm, LNL, IV-NIC, NDC, NIC, other: Head RV and Seatbelt load. Dummy Requirements and Injury Criteria for a Low-speed Rear Impact Whiplash Dummy. EEVC WG12 report, p.29, September 2007 However, some valuable insight can gained from a biomechanical review of Whiplash injuries. On the following pages, Mainstream findings will be 22 presented, Controversial research findings are not included.

23 Biomechanics of Whiplash injuries The biomechanical evidence for Whiplash injuries Classic injury criteria development For whiplash Effectiveness review thresholds Physiological damage (injury) Injury mechanism Injury criterion Injury criterion with thresholds Symptoms (short and long term) correlation 23

24 Biomechanics of Whiplash injuries Whiplash Injuries Injury mechanism Criteria Thresholds 24

25 Biomechanics of Whiplash injuries Symptoms Neck pain, headache, vision disorder, dizziness, unconsciousness, neurological symptoms and other EEVC WG12 report, p.24, September 2007 Schmitt, K.U. Trauma Biomechanics, 2 nd Edition, p.91 Syptoms and injuries are related: Nociceptors have been shown to exist in various components of spinal tissues, namely the muscle (Bogduk & Marsland 1988), disc annulus and facet joint ligaments (McLain 1994). Consequently, injury to any of these tissues has the potential to cause neck pain. Whiplash associated disorders: a comprehensive review, p. 31. Anderson et al. Centre for Automotive Safety Research. University of Adelaide. April

26 Biomechanics of Whiplash injuries Physiological damage (injuries) Yoganandan et al. (2000) reported injuries to several ligaments, the intervertebral discs and the facet joint structures. Taylor et al. (1998) and Svensson et al. (2000) reported damage in cervical spinal root ganglia Brault et al. (2000) reported muscle injuries EEVC WG12 report, p.24, September 2007 But muscle stiffness following the impact typically last only a few days Whiplash associated disorders: a comprehensive review, p. 31. Anderson et al. Centre for Automotive Safety Research. University of Adelaide. April

27 Biomechanics of Whiplash injuries Physiological damage (injuries) The structures most likely to be injured in whiplash are the facet capsule, the intervertebral discs and the upper cervical ligaments. Injuries to other structures may occur but the available evidence appears to suggest that these are less common Whiplash associated disorders: a comprehensive review, p

28 Biomechanics of Whiplash injuries Whiplash Facet joint Disc Ligaments Muscles Spinal root ganglia Injuries Injury mechanism Criteria Thresholds 28

29 Biomechanics of Whiplash injuries Injury mechanism Hyperextension of the neck not relevant any more Muscle strains unlikely and pain only last for a few days Spinal column pressure pulses could cause ganglion damage Cervical spine motion (local hyperextension/flexion) - has been shown to be able to lead to facet joint impingement Neck shear force can cause excessive facet joint strain. Neck compression can cause the facet capsules to stretch and possibly torn, resulting in inflammation and pain. Whiplash associated disorders: a comprehensive review, p

30 Biomechanics of Whiplash injuries Injury mechanism Many causes for soft tissue neck injuries are hypothesised, In practice, the S-shape deformation is regarded to play a crucial role when discussing possible injury mechanism Schmitt, K.U. Trauma Biomechanics, 2 nd edition p.94 30

31 Biomechanics of Whiplash injuries Whiplash Facet joint Disc Ligaments Muscles Spinal root ganglia Injuries local hyperextension / flexion Neck shear Neck compression Muscle strain Pressure pulse Injury mechanism Criteria Thresholds 31

32 Biomechanics of Whiplash injuries Injury criteria review Several injury criteria (response measurement) Item Who? Year Where? Associated injury mechanism NIC Bostrom '96 IRCOBI Pressure pulses in spinal ganglia Nkm Schmitt '01 ESV Excessive load (some relation with facet injury) Combination of Fx and My LNL Heitplatz '03 ESV Excessive load (some relation with facet injury) Combination of lower Neck Fx, Fz, My MIX Kullgren '03 ESV - (combination of NIC and Nkm) WIC Muñoz '05 ESV - (excessive load?) 32

33 Biomechanics of Whiplash injuries Several injury criteria (response measurement) contd. Item T1G Who? Year Where? Associated injury mechanism - (Seat design parameter) Fx (upper) Ono '09 IRCOBI Facet injury (via cervical strain) Fz (upper) Ono Fx (lower) Stemper Fz (lower) Stemper My (lower) Stemper My (upper) Ono '09 IRCOBI '07 IRCOBI '07 IRCOBI '07 IRCOBI '09 IRCOBI Facet injury (via cervical strain) Facet injury (via cervical strain) Facet injury (via cervical strain) Facet injury (excessive load and/or motion) Facet injury (excessive load and/or motion) 33

34 Biomechanics of Whiplash injuries Several injury criteria (kinematic measurement) Item Who? Year Where? Associated injury mechanism IV-NIC Panjabi '99 IRCOBI Facet joint, Disc and ligament (excessive rotation) VT1 Muser '00 IRCOBI - (excessive load in rebound phase) NDC Viano '02 SAE - (Kinematic measurement for excessive load) PWI Mallory '05 ESV - (Head rotation) Head RV T-HRC - (excessive load in rebound phase) - (Head to headrest contact timing) 34

35 Biomechanics of Whiplash injuries Injury criteria review Whiplash Facet joint Disc Ligaments Muscles Spinal root ganglia Injuries local hyperextension/ flexion Neck shear Neck compression Muscle strain Pressure pulse Injury mechanism Fx, Fz, My, IV- NIC Nkm, LNL as combination NIC MIX, NDC T1G, T-HRC, Head RV, VT1 Criteria Thresholds 35

36 Biomechanics of Whiplash injuries Injury-risk curves for thresholds derivation Kullgren 2003 Ono

37 Injury criteria thresholds with correlation to Whiplash injuries Item NIC Nkm Who? Year Where? Derived thresholds Bostrom 2000 Book Kullgren 2003 ESV 15 m/s2 (20% risk for long term injuries) (1) Ono 2009 IRCOBI 8/30 (5%/95% risk of WAD2+) Kullgren 2003 ESV 0.8 (20% risk for long term injuries) (2) Schmitt 2001 ESV 1 Fairly old findings. Nkm might correlate because Fx and My do. Thus, Fx and My should be used Fx (upper) Fz (upper) My (upper) Fx (lower) Fz (lower) My (lower) Ono 2009 IRCOBI 340/730N (5%/95% risk of WAD2+) 475/1130N Ono 2009 IRCOBI Kullgren 2003 ESV 12/40Nm 340/730N 257/1480N Values for 5%/95% risk of >1m symptoms are approx. (1) 11/28 (2) 0,5/1,7 (3) 3/8 12/40Nm 5Nm (20% risk for long term injuries) (3) (recommended to use NIC and Nkm only) 37

38 Biomechanics of Whiplash injuries Injury criteria review Whiplash Facet joint Disc Ligaments Muscles Spinal root ganglia Injuries local hyperextension/ flexion Neck shear Neck compr. Muscle strain Pressure pulse Injury mechanism (Nkm), (LNL), Fx, Fz, My, IV- NIC NIC MIX, NDC T1G, T-HRC, Head RV, VT1 Criteria Fx: N Fz: N My: 12-40Nm NIC MIX: 3.2 Thresholds 38

39 Biomechanics of Whiplash injuries Injury criteria review Summary (1): Injury criteria based on an underlying injury mechanism and are correlated with whiplash injuries exist Item Established Mechanism Correlation Thresholds NIC Bostrom 96 Pressure pulses in spinal ganglia Bostrom 00 Kullgren 03 Ono m/s2 8/30 m/s2 Nkm Fx (upper) Fz (upper) Schmitt 01 Ono 09 Excessive load (some relation with facet injury) Facet injury (via cervical strain) Schmitt 01 Kullgren 03 Ono /730N 475/1130N Nkm might correlate because Fx and My do. Thus, Fx and My should be used Fx (lower) Fz (lower) Stemper 07 Ono 09 Facet injury (via cervical strain) Ono /730N 475/1130N My upper Ono 09 Facet injury (via cervical strain) Ono 09 12/40Nm My lower Ono 09 Stemper 07 Facet injury (via cervical strain) Ono 09 Kullgren 03 12/40Nm 39 5Nm (recommended not to use)

40 Biomechanics of Whiplash injuries Summary (2) : Any other injury criterion should only be used after further thorough evaluation Item Established Mechanism Correlation Thresholds LNL Heitplatz '03 Excessive load (some relation with facet injury) - - MIX Kullgren 03 - Kullgren WIC Muñoz T1G IV-NIC Panjabi 99 Facet, disc and ligament injury (excessive rotation) - - VT1 Muser 00 - (excessive load in rebound) - - NDC Viano PWI Mallory Head RV - - Ono 09 - T-HRC

41 Biomechanics of Whiplash injuries Injury criteria review Whiplash Facet joint Disc Ligaments Muscles Spinal root ganglia Injuries local hyperextension/ flexion Neck shear Neck compr. Muscle strain Pressure pulse Injury mechanism (Nkm), (LNL), Fx, Fz, My, IV- NIC NIC MIX, NDC T1G, T-HRC, Head RV, VT1 Criteria Fx: N Fz: N My: 12-40Nm NIC MIX: 3.2 Thresholds 41

43 IIWPG rating & injury risk W/O, Cars after 97 With Anti_whiplash Whiplash System W/O, Cars before Relative LT Risk (%) Slight differences Good Acceptable Marginal Poor Not tested Kullgren et al. (ESV 2007) 43

44 IIWPG rating & injury risk Proportion of LT injuries (%) 7.0% 6.0% 5.0% 4.0% 3.0% 2.0% 1.0% 0.0% Good significantly better than poor 5.8% 4.7% 4.6% 3.8% 3.6% Only marginal significantly better than all good acceptable marginal poor all Farmer et al. (Traffic Injury Prevention 2007) 44

45 IIWPG rating & injury risk Not all questions are answered It is still a valuable exercise to compare rating and real-life risk 45

46 Injury and seat performance criteria versus injury risk EEVC WG12 Report Document Number 578 Evaluation of Seat Performance Criteria for Rear-end Impact Testing (Interim report) January 2011 Johan Davidsson, Chalmers University of Technology Anders Kullgren, Folksam Research Methods: - Analysing real life risk from Swedish insurance data ( ) of rear impacts with filed Whiplash claim -Taking proportions of Symptoms > 1 month and permanent disability -Grouping similar seats (e.g. all Volvo Whips seats) -Taking representative test values (medium pulse) for injury and seat performance measurements 46

47 Injury and seat performance criteria versus injury risk Findings: Some injury and seat performance criteria correlate with injury risk 47

48 Injury and seat performance criteria versus injury risk Findings: Some injury and seat performance criteria do not correlate with injury risk 48

49 Injury and seat performance criteria versus injury risk Findings: Some injury and seat performance criteria correlate with injury risk some do not 49

50 Injury and seat performance criteria versus injury risk Conclusion NIC, Fx (upper), Head to T1 rotation and Nkm are suggested to be included in performance evaluation of seat systems in rear-end impact. 50

51 Injury and seat performance criteria versus injury risk Findings: Some injury and seat performance criteria have limited correlation with injury risk (after removal of outliers) Conclusion Fz (lower), My (lower) are candidates for performance evaluation of seat systems in rear-end impact. 51

52 Effectiveness of different seat concepts Kullgren and Krafft, IRCOBI 2010 GENDER ANALYSIS ON WHIPLASH SEAT EFFECTIVENESS: RESULTS FROM REAL-WORLD CRASHES 52

53 Effectiveness of seat concepts for males Relative risk of permanent medical impairment for males All concepts are effective % standard seat RHR Saab other RHR WhiPS WIL 53

54 Effectiveness of seat concepts for females Relative risk of permanent medical impairment for females Do RHR protect females? 8 % standard seat RHR Saab other RHR WhiPS WIL 54

56 Criterion Biomechanical justification Real-life justification (EEVC WG12) Current J- NCAP Current Euro NCAP Ideas for Euro NCAP (open discussion) NIC Nkm ( )* Head RV Fx upper Fz upper Fx lower Fz lower My upper My lower Double evaluation ( )** ( )** Head - T1 rotation T1 x-acceleration Head restraint contact time Seatback opening Seatback rotation used to measure seatback stability for high impact loads. (no biomechanical criterion) Head RV used to measure violence of rebound. - Head velocity relative to T1 (early phase) or Neck Forces (late phase with Seatbelt interaction) seem more appropriate. -Difficult to measure (video tracking problems) -No injury-risk curves available Head T1 rotation difficult to measure (video tracking problems). Correlation with My exists. Rotation rate might be more important than amount Wrong Good / use Candidate Not used *further research needed. Fx might be more appropriate. Ono et al. conclude no correlation with facet strain. Should be excluded to avoid double evaluation **further research needed. 56 Ono et al. showed correlation with facet strain, but Kullgren and Davidsson showed no correlation to real-life risk

58 Removal of T1 acceleration, head restraint contact time, Head rebound velocity Unchanged 4 performance limits calculated rating score without T1g, T-HRC, HRV current rating score 58

59 Removal of T1 acceleration, head restraint contact time, Head rebound velocity 1.2 Unchanged performance limits change in score On average, score increases by 0.12 when T1G, T-HRC, HRV are excluded -0.8 This could be compensated for setting good-average-poor limits up by 0.12 (High increase when HRV exceeded capping value before) 59

60 Removal of T1 acceleration, head restraint contact time, Head rebound velocity Some implications by OEM Unchanged performance limits 4 Toyota Volvo & Saab current rating score 60 calculated rating score without T1g, T-HRC, HRV calculated rating score without T1g, T-HRC, HRV current rating score PSA BMW & Mercedes calculated rating score without T1g, T-HRC, HRV calculated rating score without T1g, T-HRC, HRV current rating score current rating score

62 Thresholds J-NCAP Criterion Davidson and Kullgren 2010 <6% risk of permanent injuries given initial symptoms Ono %-95% risk WAD2+ Kullgren % risk symptoms >1month Current Euro NCAP (low-mid-high) NIC /15 11/24 13/23 Nkm / / /0.47 Fx upper /110 30/190 30/210 Fz upper / / /770 Fx lower Fz lower My upper My lower

63 Extended Criteria Review Summary From the presented evidence, it is recommended to Continue using criteria with biomechanical and real life justification NIC, [Nkm], (Upper Fz), Upper Fx Discontinue using criteria without justification T1G, T-HRC, Head RV Consider introducing additional criteria with have a justification (Lower Fx), Lower Fz, Lower My, (Upper My) Consider introducing - Injury-risk based thresholds to effectively prevent injury and not to only benchmark seats () further research for real-life effect needed [] discontinuation suggested as Fx and My should be measured 63

64 Conclusion Toyota recommends to harmonise with J- NCAP A good step towards a scientifically founded rating can be achieved. J-NCAP s criteria have the best scientific justification of the ratings available and can be adopted easily. Toyota recommends to follow gtr phase 2 developments and consider harmonising 64

65 Thank you! 65