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1/11 Proposal on Thorax Injury Criteria to protect elderly occupants February 27, 2013 Jasic.

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Presentation on theme: "1/11 Proposal on Thorax Injury Criteria to protect elderly occupants February 27, 2013 Jasic."— Presentation transcript:

1 1/11 Proposal on Thorax Injury Criteria to protect elderly occupants February 27, 2013 Jasic

2 2/11 Fig Ratio of Fatal and Sever Injury, with classified into Injured body Region Reference: Japanese Police Data 2004-2006/ITARDA Information2007] Ratio of fatal and severe injury is relatively higher for elderly occupant. Thorax injury occupy the highest ratio as body region for elderly. Japanese Accident Data Ratio of Fatal and Sever Injury(%) 1.0 = Averaged Age Group Chest

3 3/11 ※ Reference : JSAE 20115636 “Analysis of Thoracoabdominal Injury based on Japanese Trauma Data Bank and In-depth accident study” Tominaga et al. Injury Mechanism of Thorax Injury Fig. Break down into type of thoracic injury(AIS2+) 胸骨骨折 Rib Fracture 11% Flail Chest 9% Multi Rib Fracture 34 % Hemothorax 11 % Lung Contusion 20% Heart Injury 9% Vena Cava 3% Aorta 3% RibsLungOther organs Ribs fracture and Lung Injury account for 90% or more as injury mechanism. Thorax compression (Deflection) by external force, is the major mechanism of thorax injury.

4 4/11 Seatbelt and steering wheel occupy the main contact part, among thorax injured cases. Injury Mechanism of Thorax Injury Steering Wheel Seat Belt Airbag Lung Rib Fracture Frail ChestSternum Fracture HeartThoracic Vessel Fig Contact parts, for each type of thoracic injury ※ Number of Injuries Steering Wheel or Airbag Seat belt or Airbag Door Panel Arm Rest Unknown ※ Reference : JSAE 20115636 “Analysis of Thoracoabdominal Injury based on Japanese Trauma Data Bank and In-depth accident study” Tominaga et al.

5 5/11 Aging effect for thorax injury To mitigate thorax injury for elderly occupant, aging effect on the tolerance should be considered. Fig. Injury Risk Curve for thorax deflection of 50%Male (2005. Laituri)

6 6/11 Our proposal on thorax injury criteria  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. We understand the scope of DEQ is to mitigate the thorax injury from the seatbelt among elderly occupant, it’s well considered, however…

7 7/11 Pod Deflection DEQ ver.2  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. Side Effects#1: Allow Greater Forward Motion 64K ODB Test: Hybrid III AM50 Dummy with 4kN Force Limiter

8 8/11 4-point Seatbelt (Force Limiter: 4kN) 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. Airbelt (Force Limiter: 4kN) Chest Deflection (THUMS V4 AM50 55K FRB) 3-popint Seatbelt 4-point Seatbelt Airbelt 0 5 10 15 20 25 30 Deflection ( % )

9 9/11 (1) Shoulder Outer Force (2) Shoulder Inner Force (3) Airbag Force Force (N) Chest Deflection (%) (1) Shoulder Outer 0.23 (2) Shoulder Inner 0.37 (3) Airbag 0.23 (4) Total =0.5*((1)+(2))+(3) 0.97 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. Frontal Impact Simulation (THUMS V4 AM50 55K FRB) Forces and Chest Deflection 11 Cases Changing force Limiter and Seatbelt Type Correlation bet. Chest Deflection and Forces Each one low correlation. Total significant correlation.

10 10/11 w/o knee airbag with knee airbag Pelvis disp-x Shoulder Inner Force without with Knee Aibag 0 10 20 30 40 50 00.10.20.30.40.5 Chest Forward Movement(m) Chest Deflection (mm) without with Knee Airbag Chest Deflection Shoulder Outer Force with Knee Airbag without  Knee airbag helps reduce shoulder inner force.  Low inner force generates small chest deflection. Frontal Impact Sled Test at 56K FRB with Hybrid III AM50 Dummy Shoulder Outer Shoulder Inner Example: Effectiveness of Knee Airbag

11 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.


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