Dynamic Response of the THOR-NT: Thorax and Abdomen MitsutoshiMasuda, Toyota Motor Corporation Sabine Compigne, Toyota Motor Europe 1
Background Distribution of AIS3+ injuries by body region and vs. seating position 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% Nb injuries/nb casualties Driver Front Passengers Rear Passengers Head Chest Abdomen Spine Upper Ext. Pelvis Lower Ext. Martin et. al, 2010: Car occupants with AIS 3+ injury, N=1219 (French data-rhône Road Trauma Registry) 2
Thorax injuries: Specificities of elderly car occupants % MAIS 3+ casulaties 60 50 40 Elderly females Young females Elderly males Young males 30 20 10 0 AIS0 AIS1 AIS2 AIS3 AIS4 AIS5 AIS6 Thorax AIS among MAIS3+ belted casualties, N=723 Elderly people (>60 YO) vs Young people (20-34 YO) (French data-rhône Road Trauma Registry 96-2006) Ifsttar-Toyota report, 2009 3
Thorax injuries: Specificities of elderly car occupants 75+yrs Steering Wheel Belt restraint webbing/buckle 65-75yrs 45-64yrs Instrument panel and below Center instrument panel and below Interior surface, excluding hardware or armrests Seat,back support 25-44yrs Airbag Other/Unknown 0% 20% 40% 60% 80% 100% NHTSA TR DOT HS 811 101: AIS2+ distribution of sources of thoracic injuries in frontal crashes (NASS-CDS 98-2007) 4
Thorax injuries: Specificities of elderly car occupants Rib w/wo hemo/pneumothorax Flail chest Internal organs/vessels Whole area (crush) Rib Sternum Internal organs/vessels & others Elderly males Old men 42 6 34 3 Elderly females Old women 46 10 28 2 Young males Young men 39 7 72 6 Young females Young women 23 4 49 6 0% 20% 40% 60% 80% 100% Distribution of different AIS3+ thoracic injuries, N=377 Elderly people (>60 YO) vs Young people (20-34 YO) (French data-rhône Road Trauma Registry 96-2006) Ifsttar-Toyota report, 2009 NHTSA TR DOT HS 811 101: Distribution of different AIS2+ thoracic injuries in frontal crashes (NASS-CDS 98-2007) 5
Thorax injuries: Rib fracture patterns Frequent lower rib fractures at buckle side w/ab Importance to assess this phenomenon to improve restraint systems w/ab wo/ab w/upper rib fractures 4 2 w/lower rib fractures 7 1 Crush Total 0 11 1 4 Shimamura et al. (2003): Injuries to chest and fracture locations of belted occupants in frontal crashes(itarda data, 83-2000) 6
Consequences for ATD chest Higher priority for elderly Assessment of injury risk for skeleton parts Assessment of injury risk under seat belt loading Asymmetrical loading Multi-points measurement Assessment of injury risk under steering wheel 7
THOR thorax geometry vs. human & HIII A humanlike rib cage geometry Allows a more realistic steering wheel lower rim contact with the lower rib cage Human THOR-NT Hybrid III Shaw et al., 2007: SAE THOR workshop 8
THOR thorax response vs. THUMS & HIII THOR simulates THUMS rib cage asymmetrical deformation The 4-point measurements can quantify the asymmetry to discriminate restraint systems THUMS ver.3 Hybrid III Thorax deformation pattern of human surrogates under belt loading 9 Thorax deflection of belted THOR-NT in 56 km/h sled test UR LR Thorax Deflection (mm) Deflection(mm) 70 60 50 40 30 20 10 0-10 UL LL 0 100 200 300 400 500 Chest Disp-x(mm) Chest Stroke(mm) LL UR UL LR
3 2.5 2 1.5 1 0.5 Abdomen injuries: Specificities of rear occupants Significant OR in yellow Significant OR in yellow 3 2.5 2.5 2.04 2 1.69 1.33 1.5 1.28 1.11 0.76 0.8 0.85 0.92 1 0.56 0.52 0.43 0.48 0.5 0 Head Chest Abdomen Spine Upper Ext. Pelvis Lower Ext. 0 Head Chest Abdomen Spine Upper Ext. Martin et al., 2010: Relative risk of AIS3+ per body region for rear passengers vs.drivers (left) and FSP (right) -OR and 95% CI (French data-rhône Road Trauma Registry 96-2006) Pelvis Lower Ext. Drivers (N=64) FSP (N=35) RSP (N=16) AIS 2+ solid organ injuries 65% 69% 37.5% AIS 2+ hollow organs injuries 35% 31% 62.5% Lamielleet al., 2006: AIS2+ solid and hollow organ injury distribution by occupant position 10
Current ATDs abdomen HIII Abdomen not instrumented JNCAP (2009) Belt slipping above the pelvis iliac crests: YES/NO THOR-NT Abdomen instrumented BUT Limited biofidelity Localized measurements 11
Proposal for a new THOR abdomen Collaborative project with Ifsttar(France) François Bermond, Gaëtan Hanen Development tasks ACCIDENT DATA > MAIN INJURY SOURCES > MAIN INJURY PATTERNS EVALUATION OF EXISTING CONCEPTS PROTOTYPES 1 IMPROVEMENTS: PROTOTYPE 2 DESIGN BRIEF LITTERATURE REVIEW > EXISTING CONCEPTS > INJURY CRITERIA Toyota/GESAC prototype THOR-NT lower abdomen Based on THOR-NT THOR-FT lower abdomen (uninstrumented) 12 HIII silicone abdomen (Rouhana, 2001)
Abdomen response evaluation Rigid-bar impacts Certification test for THOR lower abdomen 3 and 6.1 m/s Seat belt loading Based on Foster et al. (2006) Pretensioner System C 5 m/s Pretensioner System B 9.5 m/s Pretensioner System A (=2 B ) 16.5 m/s Rigid bar impact test set-up Seat belt test set-up (Foster, 2006) 13
Responses comparison: Rigid bar impact at 6.1 m/s Force (N) 10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 PMHS Corridor (Cavanaugh) Toyota/GESAC (Hardy) THOR-FT THOR-NT Silicone abdomen (Rouhana) 0 50 100 150 Penetration (mm) 14
Responses comparison: Seat belt System B 8000 7000 6000 PMHS Corridor (Foster) Toyota/GESAC THOR-FT THOR-NT Silicone abdomen (Rouhana) Force (N) 5000 4000 3000 2000 1000 0 0 20 40 60 80 100 Penetration (mm) 15
Prototype #1 Pressure sensors into THOR-NT lower abdomen Upper abdomen partially removed Prototype #1 THOR-NT (no jacket) 16
Prototype #1 biofidelity: Rigid bar impacts at 6.1 m/s 12 Prototype #1 10 THOR-NT Force (kn) 8 6 4 2 0 0 0.05 0.1 0.15 Penetration (m) 17
Prototype #1 biofidelity: Seat belt System B 8 Prototype #1 7 THOR-NT 6 Force (N) 5 4 3 2 1 0 0 0.02 0.04 0.06 0.08 0.1 Penetration (m) 18
Prototype #1 pressure sensor responses: Rigid bar impacts Good repeatability 3 Pressure (bar) 2.5 2 1.5 1 6.1 m/s 3 m/s 0.5 0 0 0.05 0.1 0.15 Time (s) Identical response of R&L sensors under symmetrical loading 19
Prototype #1 pressure sensor responses: Seat belt Good repeatability Identical response of R&L sensors under symmetrical loading Pressure peaks proportional to retraction speed Pressure (bar) System A System B System C Time (s) 20
Prototype #2 Simulations performed in parallel to guide design modifications Force (kn) Improve abdomen biofidelity(tests) 8 7 6 5 Biofidelity corridor THOR-NT Prototype #1 THOR-NT abdomen with added masses 4 3 2 THOR-NT FE Model providedby UVa& NHTSA/USDOT withoct. 2010 update from JARI/JAMA 1 0 0 0.02 0.04 0.06 0.08 0.1 Penetration (m) 21
Prototype #2 Modified pressure sensor geometry to fit THOR lower abdomen space Completion end of March 2012 Sled tests planned at Toyota Motor Corporation from April 2012 22
Conclusions THOR-NT is a suitable tool to assess chest injury risk THOR-NT with abdomen prototype #2 can assess abdominal injury risk: In OOP seat belt type tests To be confirmed in crash configurations 23
We would like to acknowledge & JAMA/JARI for their contribution to these studies 24