三岁儿童乘员胸部有限元模型的构建及损伤分析

发布时间：2018-03-12 11:43

本文选题：三岁儿童乘员　切入点：胸部损伤　出处：《天津科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：在机动车事故中,人们越来越注重对儿童乘员的安全保护。由于儿童的身体特征有异于成年人,而且肋骨较软及腔内组织器官仍未完全发育等原因,使得胸部在汽车碰撞事故中属于损伤多发部位,这些损伤严重时甚至足以致命。因此要求我们采取具有针对性的保护措施,使儿童乘员的胸部得到更有力的保护。本研究基于一名三岁儿童志CT影像,利用MIMICS软件获得各组织的点云模型,借用GEOMAGIC软件进行表面处理及曲面片划分,选用HYPERMESH软件装配及调整得到胸部几何模型,其后配合使用TRUEGRID软件构造有限元网格,并在PAMCRASH软件中赋予材料属性,最终构建具有详细解剖学结构特征的的三岁儿童乘员胸部有限元模型。参照真实撞锤实验,构造撞锤有限元模型,在PAMCRASH软件中重构撞锤实验,计算输出撞击力随时间变化的曲线及胸部变形随时间变化的曲线,并处理得到撞击力与胸部变形的关系曲线,真实实验的分析结果作对比,验证了该模型的有效性。根据目前普遍使用的三岁儿童安全座椅的形状,利用HYPERMESH软件构造了简化的儿童安全座椅有限元模型,配合已构建的三岁儿童乘员胸部有限元模型模拟汽车正面碰撞事故,通过改变汽车儿童安全座椅的安装方向、肩带宽度、安全带延伸率及靠背倾角等结构、材料参数,设计了 15项实验,对得到的不同结构条件下儿童乘员胸部各组织所受应力情况进行对比分析,得出:(1)对于三岁儿童乘员,必须配备儿童安全座椅。(2)相比后向安装,前向安装更有利于三岁儿童乘员胸内软组织的保护。(3)可根据使用者的体质配用相应宽度的肩带,亦可根据正常人各器官所能承受的应力极限对肩带宽度进行调整,将各软组织的损伤降至最轻。(4)当安全带延伸率在[8%,14%]区间内,使用延伸率较大的安全带更能保护三岁儿童乘员胸部的安全。但同时对于部分心脏或肺脏强度较弱的乘员,建议不要配用延伸率过大的安全带。(5)当靠背倾角在[0°,10°]的范围内,设计较大靠背倾角更能对三岁儿童乘员胸部起到保护作用。但同时对于有支气管或肺动脉缺陷的乘员,建议不要将靠背倾角调的过大。
[Abstract]:In motor vehicle accidents, people pay more and more attention to the safety protection of child occupants. Due to the fact that the physical characteristics of children are different from those of adults, and the ribs are softer and the organs in the lumen are still not fully developed, It makes the chest part of the car crash more often, which can even be fatal when it's serious. So we need to take targeted protective measures. Based on the CT images of a three-year-old child, the point cloud model of each tissue was obtained by using MIMICS software, and the surface treatment and surface slice partition were performed by using GEOMAGIC software. HYPERMESH software was used to assemble and adjust the geometric model of the chest, then the finite element mesh was constructed with TRUEGRID software, and the material attributes were assigned to PAMCRASH software. Finally, a three-year-old child's chest finite element model with detailed anatomical characteristics was constructed. According to the actual hammer experiment, the finite element model of the hammer was constructed, and the hammer experiment was reconstructed in PAMCRASH software. The curves of the impact force with time and the curve of the deformation of the chest with time are calculated, and the curves of the relationship between the impact force and the deformation of the chest are obtained. The analysis results of the real experiments are compared. The validity of the model is verified. According to the shape of the three-year-old child's safety seat, a simplified finite element model of the child's safety seat is constructed by using HYPERMESH software. According to the finite element model of the three-year-old child's chest, the material parameters were changed by changing the installation direction, shoulder band width, seat belt elongation and back inclination angle of the car's children's safety seat, and by changing the installation direction of the seat, the width of the shoulder band, the elongation of the seat belt, the angle of the back of the car, etc. A total of 15 experiments were designed to compare and analyze the stress in the chest tissues of the child occupants under different structural conditions. It was concluded that: 1) for three-year-old child occupants, they must be equipped with a child's safety seat. The forward installation is more favorable to the protection of soft tissue in the chest of the three-year-old child. It can be matched with shoulder straps of corresponding width according to the body of the user, and can also be adjusted according to the stress limit of each organ of the normal person. Reduce the injury of each soft tissue to the lightest. 4) when the seat belt elongation is in the range of [80.14%], the use of a seat belt with a higher elongation rate can better protect the chest of a three-year-old child. But at the same time, for some occupants with weaker heart or lung strength, It is recommended not to use a seat belt with an excessive elongation. (5) when the back inclination angle is in the range of [0 掳to 10 掳], the design of a larger backrest angle is more protective to the chest of a three-year-old child. But at the same time, for passengers with defects in the bronchus or pulmonary artery, It is recommended not to adjust the back angle too much.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U467.14

【参考文献】