行人下肢高精度数值模型与损伤参数研究

Development and Injury Parameters Research of a FE Model of Lower Limb with High Precision for Adult Pedestrians

为了深入研究汽车-行人碰撞过程中下肢的生物力学响应和损伤机理,基于人体解剖学结构建立了具有完整下肢组织结构和高仿生精度的成年男性行人下肢有限元模型.包括股骨、胫骨、腓骨、髌骨等下肢骨骼以及皮肤、肌肉、韧带、关节囊、半月板等重要软组织.针对长骨骨干断面几何不均匀的特征,提出以CT断面影像数据为依据,建立以真实皮质骨内外表面为边界实现皮质骨断面厚度和形状连续变化的长骨数值模型,对不同建模方式进行了对比,采用两层实体单元模拟皮质骨以获得相对较高的计算精度和计算效率.通过模拟相关生物力学实验,获得了行人下肢各部位的损伤参数,分析了皮质骨厚度变化以及不同撞击方向对下肢损伤参数和损伤机理的影响.上述损伤参数的获得可为我国汽安全性设计提供参考.

In order to study the biomechanical response and injury mechanisms of pedestrian＇s lower limb during impact, a three-dimensional FE model of lower limb for adult pedestrians with high precision was developed on the basis of human anatomical structure. The lower limb model included complete anatomical structure of femur, tibia, fibula, patella as well as soft tissues such as skin, fresh, ligaments, capsule meniscus and cartilage. Considering the nonuniformity of the section of cortical hone, a long hone model was developed based on CT data with the thickness and the shape of the cortical bone section varying continuously. In comparison with other modeling methods, cortical bone was modeled with two-layer solid elements to obtain higher precision and efficiency. The injury criterions of pedestrians＇ lower limb such as the ultimate bending moment of femur and tibia were obtained by modeling related biomechanieal experiments. In addition, the influence of the thickness of cortical bone and the impact direction to injury mechanism and injury parameters of lower limb were analyzed. The injury parameters can provide important reference for the design of cars.