Thorax Injury Criteria to elderly JASIC 2013

Transcript

1. https://slideplayer.com/slide/7347120/, Viewed Jan. 2024 Proposal on Thorax Injury Criteria to protect elderly occupants February 27, 2013 Jasic 1/11
2. Japanese Accident Data Chest 1.0 = Averaged Age Group Ratio of Fatal and Sever Injury(%) Ratio of fatal and severe injury is relatively higher for elderly occupant. Thorax injury occupy the highest ratio as body region for elderly. Fig Ratio of Fatal and Sever Injury, with classified into Injured body Region Reference: Japanese Police Data 2004-2006/ITARDA Information2007] 2/11
3. Injury Mechanism of Thorax Injury Ribs fracture and Lung Injury account for 90% or more as injury mechanism. Thorax compression (Deflection) by external force, 胸部AIS2以上の傷害内容とその分布 is the major mechanism of thorax injury. Rib Fracture 胸骨骨折 胸郭骨折 11%11% Aorta 大動脈損傷 3% 3% Vena Cava 大静脈損傷 3% 3% 心損傷 9% 9% Heart Injury Flail Chest 動揺胸郭 9%9% 肺挫傷 20% 20% Lung Contusion Multi Rib 多発肋骨 Fracture 34 % 骨折 34% Ribs ▪▪▪ 肋骨骨折 Hemothorax 11 % 血気胸 11% ▪▪Lung 肺損傷 Other organs ▪▪▪ 胸部器官の損傷 Fig. Break down into type of thoracic injury(AIS2+) ※Reference：JSAE 20115636 “Analysis of Thoracoabdominal Injury based on Japanese Trauma Data Bank and In-depth accident study” Tominaga et al. 3/11
4. Injury Mechanism of Thorax Injury Seatbelt and steering wheel occupy the main contact part, among thorax injured cases. 車内接触箇所別 胸部傷害内容の分布 8 ｽﾃｱﾘﾝｸﾞﾎｲｰﾙ Steering Wheel ｼｰﾄﾍﾞﾙﾄ Seat Belt Airbag ｴｱﾊﾞｯｸﾞ Steering Wheel orｴｱﾊﾞｯｸﾞ Airbag ｽﾃｱﾘﾝｸﾞﾎｲｰﾙor Seat belt orｴｱﾊﾞｯｸﾞ Airbag ｼｰﾄﾍﾞﾙﾄor Door Panel ﾄﾞｱﾊﾟﾈﾙ Arm Rest ｱｰﾑﾚｽﾄ Unknown 不明 7 6 Number of傷 5 Injuries 害 4 件 数 3 2 1 0 Thoracic Heart 胸部血管損傷 心損傷 Vessel Lung 肺挫傷 Rib Fracture Frail Chest Sternum 多発肋骨骨折 動揺胸郭 胸郭骨折 Fracture Fig Contact parts, for each type of thoracic injury ※ ※Reference：JSAE 20115636 “Analysis of Thoracoabdominal Injury based on Japanese Trauma Data Bank and In-depth accident study” Tominaga et al. 4/11
5. Aging effect for thorax injury To mitigate thorax injury for elderly occupant, aging effect on the tolerance should be considered. 100 AIS3+ Injury Risk（%） 90 80 70 60 AIS3+ 50M(35YO) AIS3+ 50M(45YO) AIS3+ 50M(65YO) 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 Thorax Deflection（ｍｍ） 90 100 110 120 Fig. Injury Risk Curve for thorax deflection of 50%Male (2005. Laituri) 5/11
6. Our proposal on thorax injury criteria We understand the scope of DEQ is to mitigate the thorax injury from the seatbelt among elderly occupant, it’s well considered, however… ➢Anxiety about Side Effects* of DEQ. ➢Propose to use Chest Deflection. ➢Develop Target Value for Elderly Protection. *Side Effects: #1: DEQ allows greater forward motion. #2: DEQ underestimates effectiveness of other seatbelt system such as 4-point seatbelt and airbelt. 6/11
7. Side Effects#1: Allow Greater Forward Motion ➢DEQ encourages low seatbelt force. ➢Low seatbelt force allows greater forward motion, contact with steering wheel, greater chest deflection. ➢DEQ is lower sensitive to steering wheel contact. Pod Deflection DEQ ver.2 64K ODB Test: Hybrid III AM50 Dummy with 4kN Force Limiter 7/11
8. Side Effects#2: Underestimate Other System ➢Chest deflections with 4-point seatbelt and airbelt are smaller than 3-point seatbelt at same force level. ➢DEQ underestimates their effectiveness. Deflection （%） 30 25 20 15 10 5 0 3-popint Seatbelt 4-point Seatbelt (Force Limiter: 4kN) 4-point Seatbelt Airbelt Chest Deflection (THUMS V4 AM50 55K FRB) Airbelt (Force Limiter: 4kN) 8/11
9. Reason: Overestimate of Shoulder Outer Force ➢Chest deflection is generated by (1) shoulder outer force, (2) shoulder inner force and (3) airbag force. ➢Shoulder inner force is NOT used to calculate DEQ. Force (N) (1) Shoulder Outer Force Correlation bet. Chest Deflection and Forces 10000 1)Shoulder Outer 2)Shoulder Inner 3)Airbag 4)Total 8000 (3) Airbag Force 6000 (2) Shoulder Inner Force 4000 2000 11 Cases Changing force Limiter and Seatbelt Type 0 Frontal Impact Simulation (THUMS V4 AM50 55K FRB) 0 10 20 Chest Deflection (%) (1) Shoulder Outer 0.23 (2) Shoulder Inner 0.37 (3) Airbag 0.23 (4) Total 0.97 =0.5*((1)+(2))+(3) 30 Forces and Chest Deflection Each one low correlation. Total significant correlation. 9/11
10. Example: Effectiveness of Knee Airbag Pelvis disp-x Shoulder Outer Belt Force(kN) 10 Shoulder Inner Force 8 without 6 with Knee Aibag 4 2 10 0 Shoulder Outer Force 8 6 4 without 2 w/o knee airbag 0.1 0.2 0.3 0.4 Chest Forward Movement(m) 0.5 50 Shoulder Outer Shoulder Inner with Knee Airbag 0 0 0 Chest Deflection (mm) with knee airbag Shoulder Inner Belt Force(kN) ➢Knee airbag helps reduce shoulder inner force. ➢Low inner force generates small chest deflection. 0.1 0.2 0.3 0.4 Chest Forward Movement(m) 0.5 Chest Deflection 40 without 30 20 with Knee Airbag 10 0 0 0.1 0.2 0.3 0.4 Chest Forward Movement(m) Frontal Impact Sled Test at 56K FRB with Hybrid III AM50 Dummy 0.5 10/11
11. Summary ➢Anxiety about Side Effects of DEQ. #1: DEQ allows greater forward motion. #2: DEQ underestimates effectiveness of other seatbelt system such as 4-point seatbelt and airbelt . Propose to use Chest Deflection. 11/11