年龄因素对行人下肢有限元建模及损伤的影响研究

发布时间：2018-02-11 11:22

本文关键词： 行人下肢年龄汽车-行人碰撞有限元模型长骨骨折　出处：《湖南大学》2016年硕士论文　论文类型：学位论文

【摘要】：行人直接暴露在交通环境中,是道路交通使用者中的弱势群体,而行人下肢是最易受到伤害和致残的部位之一。随着人口老年化的增长,老年人在交通事故中的比例逐年增加。然而,相对于50百分位成人,老年人在汽车碰撞事故中更易受到重伤和死亡。但是现有的行人保护法规和人体有限元模型等并没有考虑到年龄多样性的差别。因此,本文在文献研究的基础上,对两种代表年龄下肢有限元模型的建模方法以及损伤机理进行研究。本文首先研究并总结了年龄对骨骼、韧带等生物材料力学性能以及长骨几何结构的影响,在此基础上对GHBMC下肢有限元模型进行改进,包括模型的材料参数的调整,以及运用网格变形技术对股骨、胫骨的网络进行了缩放,从而建立了具有年龄特征的行人下肢有限元模型。然后根据生物力学试验,对下肢有限元模型进行了长骨三点弯曲、膝关节四点弯曲、整体下肢弯曲和剪切等验证仿真试验,从部件到组件验证了模型的有效性。最后,利用该模型对一例带有下肢损伤的车-行人事故案例进行了损伤重建,在重建的基础上对比了两种年龄下肢模型的损伤情况。研究结果表明,随着成人年龄的增长骨骼的强度逐渐下降,股骨和胫骨的耐受限度都呈现减小的趋势,80岁老年人股骨和胫骨的耐受限度分别只有30岁年轻人的68.8%和74.1%。将年龄因素的影响纳入下肢有限元模型的建模,将进一步提高模型的生物逼真度。通过损伤重建表明,老年人下肢在事故中长骨骨折的损伤风险比年轻人高,老年人股骨骨折时的von Mises等效应力为100MPa,而年轻人骨折时的von Mises等效应力约为129MPa。老年人胫骨和腓骨骨折时的von Mises等效应力约为114MPa,而年轻人胫腓骨没有出现骨折现象,表明模型对不同年龄行人的下肢损伤风险有一定的预测能力。本研究构建了具有详细解剖学结构的两种年龄行人下肢模型,并利用模型进行了下肢损伤机理的对比研究,仿真计算的结果可作为研究不同年龄下肢损伤耐受限度的理论参考依据。
[Abstract]:Pedestrians are directly exposed to the traffic environment, and they are a vulnerable group among road traffic users, and the lower limbs of pedestrians are one of the most vulnerable and maimed parts. The proportion of older people in traffic accidents increases year by year. However, compared with adults in the 50th percentile, The elderly are more vulnerable to serious injury and death in car crash accidents. However, the existing pedestrian protection laws and human finite element models do not take into account the difference of age diversity. In this paper, the effects of age on biomechanical properties of bone and ligaments and geometric structure of long bones are studied and summarized. On this basis, the GHBMC lower limb finite element model is improved, including the adjustment of the material parameters of the model, and the use of mesh deformation technology to scale the femur and tibia network. According to the biomechanical test, the finite element model of the lower limb is verified by three point bending of the long bone, four point bending of the knee joint, the bending of the whole lower limb and the shear of the whole lower extremity. The validity of the model is verified from component to component. Finally, the model is used to reconstruct a vehicle-pedestrian accident case with lower limb injury. On the basis of reconstruction, the injuries of two kinds of age lower limb models were compared. The results showed that the strength of bone decreased gradually with the increase of adult age. The tolerance limits of femur and tibia were decreased. The tolerance limits of femur and tibia in 80 year old people were only 68.8% and 74.1 of those of 30 years old, respectively. The influence of age factors was incorporated into the modeling of lower extremity finite element model. The biological fidelity of the model will be further improved. Injury reconstruction shows that older people have a higher risk of injury to long bone fractures in the lower extremities than young people. The von Mises equivalent stress of femoral fractures in the elderly was 100 MPA, and the equivalent stress of von Mises in the young was about 129 MPA. The equivalent stress of von Mises in the elderly with tibia and fibula fractures was about 114 MPA, but there was no fracture in the tibia and fibula in the young. The results show that the model can predict the lower limb injury risk of pedestrians of different ages. In this study, two kinds of lower extremity models with detailed anatomical structure were constructed, and the mechanism of lower extremity injury was compared by using the model. The simulation results can be used as a theoretical reference for studying the limits of lower limb injury tolerance at different ages.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U467.14

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