Hayashi Shigeki, Yasuki Tsuyoshi, Kitagawa Yuichi
Toyota Motor Corporation, Toyota, Aichi, 471-8572 Japan.
Stapp Car Crash J. 2008 Nov;52:363-77. doi: 10.4271/2008-22-0015.
When a car collides against a pole-like obstacle, the deformation pattern of the vehicle body-side tends to extend to its upper region. A possible consequence is an increase of loading to the occupant thorax. Many studies have been conducted to understand human thoracic responses to lateral loading, and injury criteria have been developed based on the results. However, injury mechanisms, especially those of internal organs, are not well understood. A human body FE model was used in this study to simulate occupant kinematics in a pole side impact. Internal organ parts were introduced into the torso model, including their geometric features, material properties and connections with other tissues. The mechanical responses of the model were validated against PMHS data in the literature. Although injury criterion for each organ has not been established, pressure level and its changes can be estimated from the organ models. Finite element simulations were conducted assuming a case where a passenger vehicle collides against a pole at 29km/h. Occupant kinematics, force-deformation responses and pressure levels were compared between cases with and without side airbag deployment. The results indicated that strain to the ribs and pressure to the organs was smaller with side airbag deployment. The side airbag widened the contact area at the torso, helping to distribute the force to the shoulder, arm and chest. Such distributed force helped generate relatively smaller deformation in the ribs. Furthermore, the side airbag deployment helped restrict the spine displacement. The smaller displacement contributed to lowering the magnitude of contact force between the torso and the door. The study also examined the correlations between the pressure levels in the internal organs, rib deflection, and VC of chest. The study found that the VC(t) peak appeared to be synchronized with the organ pressure peak, suggesting that the pressure level of the internal organs could be one possible indicator to estimate their injury risk.
当汽车撞上杆状障碍物时，车身侧面的变形模式往往会延伸到其上部区域。一个可能的后果是乘员胸部的负荷增加。已经进行了许多研究来了解人体胸部对侧向负荷的反应，并根据研究结果制定了损伤标准。然而，损伤机制，尤其是内部器官的损伤机制，尚未得到充分了解。本研究使用人体有限元模型来模拟杆侧碰撞中的乘员运动学。将内部器官部分引入躯干模型，包括它们的几何特征、材料特性以及与其他组织的连接。该模型的力学响应与文献中的PMHS数据进行了验证。虽然尚未建立每个器官的损伤标准，但可以从器官模型中估计压力水平及其变化。进行了有限元模拟，假设一辆乘用车以29公里/小时的速度撞上一根杆子。比较了有和没有侧面安全气囊展开的情况下的乘员运动学、力-变形响应和压力水平。结果表明，展开侧面安全气囊时，肋骨的应变和器官的压力较小。侧面安全气囊拓宽了躯干处的接触面积，有助于将力分散到肩部、手臂和胸部。这种分散的力有助于使肋骨产生相对较小的变形。此外，展开侧面安全气囊有助于限制脊柱位移。较小的位移有助于降低躯干与车门之间的接触力大小。该研究还检查了内部器官压力水平、肋骨挠度和胸部VC之间的相关性。研究发现，VC(t)峰值似乎与器官压力峰值同步，这表明内部器官的压力水平可能是估计其损伤风险的一个可能指标。
