基于典型交通事故的颅脑损伤力学机制研究

发布时间：2018-05-25 14:44

本文选题：颅脑撞击伤 + 交通事故　；参考：《第三军医大学》2013年硕士论文

【摘要】：颅脑撞击伤是交通事故中常见的伤类，根据国外统计资料，颅脑撞击伤的发生率高达54％，是伤后致死、致残的首要原因。行人在道路交通事故中处于弱势地位，再加上我国人车混杂的复杂道路环境，使我国成为行人交通事故多发的国家之一，而颅脑损伤是导致行人死亡的主要原因，因此对行人颅脑撞击伤的研究具有重要意义。目前，用于实验研究的模型包括人尸体模型、动物模型、物理模型以及力学分析模型。动物和人体在结构、外形和受力过程等诸方面存在较大差异，无法将动物实验的定量结果直接推广到人体上。尸体具有和活体相同的解剖结构，但因组织降解，缺少冲击对机体造成的生理或病理反应的直接观察。物理模型稳定性好，，避免了生物材料的个体差异，但主要适用于理论研究。建立力学分析模型来进行伤害机理的分析是非常必要的手段，它能相对容易地在模型的指定位置上计算出因撞击而引起的颅脑组织的应力和应变，从而对组织的受伤与否和伤害程度做出判断。但模型中颅骨往往被定义为刚体，颅骨变形对大脑冲击响应的影响无法估测，且通过这些力学模型计算出的结果还必须通过实验研究进行验证，限于实验条件的限制，有些结果是可以验证的而部分结果是无法验证的。而在道路交通事故中频繁发生的行人交通事故是更理想的研究资源，采用真实交通事故结合力学分析模型进行研究，可弥补上述研究工作中的不足之处。本研究选择有监控录像或事故信息详细的车-人交通事故以获取事故发生过程，对伤亡人员进行CT断层扫描获取损伤细节，并用3D激光扫描系统采集事故车辆和现场信息。在此基础上结合多刚体动力学软件MADYMO和有限元分析软件LS-DYNA进行事故过程和人体损伤过程的重建。通过典型交通事故的深度分析和颅脑力学模型的有限元分析，开展真人颅脑损伤的量效关系研究，分析行人头部各种物理参数与损伤风险的关系，进而深入探讨其生物力学机制。为行人头部损伤防护、颅脑交通伤的临床治疗、汽车安全设计提供参考依据，具有现实的经济和社会意义。主要研究方法和结论：（1）典型行人交通事故案例的采集与分析本研究中全部案例均由作者在导师团队成立的交通事故司法鉴定中心的平台上进行采集，每一案例均记录了详细的信息，这些信息可以分为事故数据、伤情数据、车辆信息和碰撞数据，全部案例均在重庆市内采集，其中7例有监控录像，能清晰看见整个事故过程以及行人碰撞时的姿态，空中飞行姿态，能通过视频分析法分析出车辆-行人碰撞速度、车辆减速度、行人抛掷距离等信息；另外4例有目击证人，能准确确定碰撞点以及详细的车辆、行人信息。选择的依据是：行人遭受了AIS2级以上的头部损伤。（2）基于车-人事故过程重建的颅脑力学响应分析使用多刚体动力学仿真分析软件MADYMO建立汽车-行人碰撞仿真模型，通过对事故过程的模拟，研究事故发生时车辆以及行人的运动轨迹，从空间和时间上确定事故每个阶段的发生过程。通过分析与人体损伤相关的力学响应参数，预测和评估汽车-行人相撞事故中行人头部的损伤风险。结果显示，车辆碰撞速度越高，行人颅脑损伤越严重；SUV型车撞击行人时，行人颅脑损伤严重度相对于轿车和面包车撞击行人时高；行人颅脑损伤严重度与行人不同部位受到撞击有关；行人头部与地面接触是低速（20、30km/h）撞击行人时，行人颅脑损伤严重的原因，而碰撞速度大于等于40km/h时，行人头部损伤主要是与车辆接触所致。（3）基于THUMS模型的颅脑损伤过程重建利用一例典型的汽车-行人交通事故案例，基于THUMS人体模型进行了损伤过程的再现，并将仿真分析结果与CT扫描结果和尸检结果进行了比较分析，说明了利用有限元仿真分析技术进行行人损伤过程再现的可行性和THUMS4.0人体模型的有效性。（4）行人颅脑损伤力学机制分析通过多刚体动力学方法进行事故过程重建，以获得行人头部的动力学响应过程，将其作为初始条件，利用有限元分析法在THUMS4.0头部有限元模型基础上对行人损伤过程进行重建，进行真人颅脑损伤力学机制的研究。结果显示，当颅内压力超过301kpa时，或者当脑部等效应力超过16.5kpa时，行人会出现严重颅脑损伤；当颅骨等效应力超过10.09mpa时，行人颅骨出现骨折。
[Abstract]:Head injury is a common injury in traffic accidents . According to the statistics of foreign countries , the incidence of craniocerebral injury is as high as 54 % , which is the leading cause of death and disability after injury .

The model includes human body model , animal model , physical model and mechanical analysis model .

Based on the deep analysis of typical traffic accidents and the finite element analysis of the brain mechanics model , the relationship between the physical parameters and the risk of injury of human body is studied .

Main research methods and conclusions :

( 1 ) Collection and analysis of typical pedestrian traffic accident cases

All the cases in this study were collected by the author on the platform of the Traffic Accident Judicial Identification Center established by the mentor team . Each case records detailed information , which can be divided into accident data , injury data , vehicle information and collision data . All the cases are collected in Chongqing . Among them , 7 cases have monitoring videos , which can clearly see the whole accident process and the attitude and air flying attitude during pedestrian collision , and can analyze the vehicle - pedestrian impact speed , vehicle deceleration , pedestrian throwing distance and so on through video analysis .
The other 4 cases have witnessed witness , can accurately determine the impact point and detailed vehicle , pedestrian information . The choice is based on : pedestrian suffers from head injury above AIS2 level .

( 2 ) Response analysis of craniocerebral mechanics based on vehicle - person accident process reconstruction

The vehicle - pedestrian collision simulation model is established by using the multi - rigid body dynamics simulation analysis software MADYMO . Through the simulation of the accident process , the movement locus of the vehicle and the pedestrian is studied , and the occurrence process of each stage of the accident is determined from the space and time .
when the SUV - type vehicle impacts the pedestrian , the severity of the pedestrian craniocerebral injury is higher than when the pedestrian is struck by the car and the minivan ;
the severity of the pedestrian craniocerebral injury is related to the impact of different parts of the pedestrian ;
When the pedestrian head is in contact with the ground at a low speed ( 20,30 km / h ) , the pedestrian head injury is serious , and when the collision speed is greater than or equal to 40 km / h , the pedestrian head injury is mainly caused by contact with the vehicle .

( 3 ) Reconstruction of craniocerebral injury process based on THUMS model

Based on THUMS human body model , a typical case of vehicle - pedestrian traffic accident is presented , and the results of simulation are compared with CT scan results and autopsy results . The feasibility of using finite element simulation technique to reproduce the pedestrian damage process and the validity of THUMS4.0 human body model are described .

( 4 ) Analysis of mechanical mechanism of pedestrian craniocerebral injury

The method of multi - rigid body dynamics is used to reconstruct the accident process so as to obtain the dynamic response process of the pedestrian ' s head . As an initial condition , a finite element analysis method is used to reconstruct the pedestrian injury process on the basis of THUMS4.0 head finite element model . The results show that when the intracranial pressure exceeds 301kpa , or when the effect force of the brain exceeds 16.5kpa , severe brain injury can occur ;
When the effect force of skull and the like exceeds 10.09mpa , fractures occur in the pedestrian skull .
【学位授予单位】：第三军医大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：U491.31;R651.15

【参考文献】