【作者】 阮诚心（NGUYEN THANH TAM）；

【导师】 曹立波；

【作者基本信息】 湖南大学 ， 车辆工程， 2012， 博士

【摘要】 客车作为城市市区及城际之间重要的公共交通运输工具，具有载客量大、单位运输成本低的特点，对缓解城市交通拥堵压力起着重要的作用。客车在现代集体运输系统中占有重要的比重。中国公安部交通管理局统计年报显示，从2004年起，平均每年增长4.5%，2010年全国大型和中型客车保有量达到了262万辆。但是，随着客车保有量、乘坐人次的快速增加和高速公路行驶速度的提升，客车交通事故数量也不断地增加，并且由于客车较大的载客量，一旦发生事故，极易成为重大甚至特大事故，造成大规模的乘员伤亡。客车交通事故的形态包括正面碰撞、侧面碰撞、追尾碰撞、护栏碰撞和侧翻等。其中，客车侧翻容易导致车身上部结构发生严重变形，造成对车身内部的侵入，从而危及乘员的生命安全。因此，客车侧翻安全性以及客车侧翻乘员保护成为客车行业的重要研究课题。目前，关于大客车侧翻安全性的代表性法规为欧洲ECE R66法规。该法规规定了大客车车身上部结构强度刚度的要求，这对于客车侧翻碰撞安全性改进设计和乘员生命安全保护具有重要意义。当前，国内外对于客车侧翻安全性研究主要是根据欧洲ECE R66法规要求，对客车车身上部结构强度刚度进行分析和对客车侧翻碰撞过程中乘员损伤进行研究，其研究工作虽然开展得较多，但是还存在一些问题需要深入研究。本文在查阅大量文献的基础上，使用试验分析方法、有限元分析方法、多刚体分析方法和优化设计方法，分别对客车侧翻安全性改进、客车车身结构优化和客车侧翻碰撞过程中的乘员损伤进行了研究。主要研究内容及创新点如下：1.客车侧翻安全性改进研究。根据某款客车CAD模型建立了客车整车有限元模型，采用有限元分析软件LS-DYNA模拟了客车侧翻时车身的动力学响应。针对原车身结构在侧翻安全性方面存在的问题，提出了基于管内填充方法的结构改进方案。为了满足客车车身的轻量化要求，同时考虑到填充工艺的方便性，除采用石蜡、松香等轻质材料作为填充剂外，还专门配置了一种新型填充材料，即环氧树脂与木屑和固化剂的混合物。仿真及试验结果表明，三者都可使车身上部结构刚度得到明显提高。但是，在高温环境中，石蜡和松香的填充效果迅速下降，而环氧树脂与木屑及固化剂的混合物性能稳定。同时对环氧树脂与木屑及固化剂的混合物填充改进后的客车仿真，结果表明车身骨架在侧翻时没有与乘员生存空间发生相互穿透，满足了ECE R66法规要求。2.客车车身结构优化。由于填充物的填充量和骨架壁厚会影响到整车的质量，以车身的轻量化为优化目标，对该客车的车身骨架结构进行了优化设计。采用均匀试验设计方法对车身侧围立柱和顶横梁的壁厚及管内填充长度等设计变量进行了试验设计，采用SAS软件对仿真结果进行回归分析并建立了回归函数，利用MATLAB软件对设计变量进行了优化，并根据优化结果进行了侧翻安全性仿真模拟。仿真结果表明，客车车身在满足ECE R66法规对生存空间要求的情况下，侧围立柱和顶横梁优化后的结构比原结构质量减轻了23.7%，实现了车身结构轻量化。3.客车侧翻碰撞中乘员损伤研究。在客车的侧翻过程中，乘员与乘员以及乘员与车体内部结构之间会发生复杂的碰撞，从而可能导致乘员损伤加剧。利用MADYMO软件建立了该客车局部车身段的侧翻有限元与多刚体混合模型，并进行了侧翻仿真分析，使其变形、碰撞加速度等仿真结果与该车型的有限元仿真结果基本一致，从而可以取代有限元方法进行侧翻仿真分析。通过在该MADYMO模型的碰撞侧座椅上分别放置单个和两个佩戴两点式、三点式、四点式安全带的侧碰假人Euro SID-I，研究了侧翻过程中乘员的损伤情况及乘员间的相互作用对乘员损伤的影响。仿真结果表明，满足ECE R66法规要求的客车在侧翻过程中仍然可能对乘员的一些部位造成较大的损伤，且客车侧翻过程中乘员相互作用会导致乘员的损伤更严重。4.客车车身上部结构变形侵入乘员生存空间程度对乘员损伤的影响研究。基于客车原有结构分别按五级增大车身上部结构刚度，不同程度的增大乘员的生存空间，或按五级减小车身上部结构刚度，不同程度的增加结构变形对乘员生存空间的侵入，并在MADYMO模型的碰撞侧座椅上分别放置一个和两个佩戴两点式安全带的侧碰假人Euro SID-I，分析研究侧翻过程中客车车身上部结构的刚度在不同程度的增加或减小的条件下对乘员损伤情况的影响。仿真结果表明，车身上部结构不同程度远离或侵入乘员的生存空间，均无法避免乘员与车身侧围结构的碰撞，增大车身上部结构的刚度会增大乘员的损伤，减小车身上部结构的刚度会对乘员发生严重挤压作用。当客车车身上部结构变形达到法规规定的乘员生存空间边缘±20mm的范围时，乘员损伤值最小，获得对乘员的最佳保护。5.客车侧窗玻璃破碎条件下的乘员损伤研究。基于客车车身上部结构变形正好满足乘员生存空间要求，针对客车在侧翻碰撞过程中侧窗玻璃破碎的情况，通过在该MADYMO模型的碰撞侧座椅上分别放置单个和两个佩戴两点式安全带的侧碰假人Euro SID-I对乘员损伤的影响进行研究。仿真结果表明，在侧翻过程中车窗打开或玻璃破碎会导致乘员头部和颈部产生更大损伤，保证车窗玻璃的完整会对乘员产生较好的保护作用。更多还原

【Abstract】 Based on the great advantage of low cost and large passenger capacity, busplays a great role on easing traffic congestion as an important urban and intercitypublic transportation tool. Meanwhile, bus accounts for an important proportion inmodern transportation systems. According to the statistic reports published by theTraffic Management Bureau of China Police Ministry in2010, the number of largeand middle bus in China reached2.62million with an average increasing speed of4.5%per year from2004. However, along with the increase of the number of buses,the number of passengers and the speed on the highway, the number of bus accidentswere also increased incessantly. Since the bus carries many passengers, the busaccident can be a serious or an extra serious accident and results many casualties.The types of bus accidents include front crash, side crash, rear crash, guardrail crash,rollover crash and so on. In bus rollover crash, the occupant survival space isintruded by serious deformation of bus body upper structure, which can cause severeinjuries of occupants. Therefore, the safety performance of bus and the protection ofoccupants during a rollover crash have become an important research topic for busmanufacturers.At present, the European regulation ECE R66is a representative regulationregarding to the safety performance of bus during a rollover crash. The strength andstiffness of bus upper structure are required in this regulation, which is important toimprove the safety performance and the occupant protection. At present, the researchat home and abroad related to bus rollover crash safety mainly concentrated on thestrength and stiffness of bus upper structure and the occupant injury according to theECE R66. These researches were carried out more but there are also some problemsexisting must be deeply studied.Based on the massive literature review, this thesis focused on the studies of theimprovement of bus rollover safety，the structure optimization of bus body and theoccupant injury by using experimentation analysis method, finite element analysismethod, multi-body analysis method and optimization design method. The mainresearch and innovative points of this thesis are as follows.1. Improvement of bus rollover safety. According to the bus CAD modelprovided by manufacturer, the finite element model of the bus was developed and theLS-DYNA software was used to simulate the dynamic response during the rollover process. In accordance with existing problems of the original bus body structure, thecountermeasur of tube filling was proposed. In order to achieve the requirements oflight-weighting the bus body and consider the convenience of filling technology, anew filling composite which includes epoxy resin, wood flour and hardening agentwas used, besides other lightweight materials such as paraffin and colophony. Theresults of simulation and test show that using paraffin, colophony or the newcomposite material to fill the suitable place of rectangular steel tubes can increasethe stiffness of the bus body structure. But the filling effect of paraffin, colophonydecrease at high temperature, and the stabilization of new composite material isbetter than others. The simulation of new composite material results also show thatthe improved bus body structure does not penetrate into occupant living space duringrollover crash, and the regular requirements can be met.2. Structure optimization of bus body. The volume of fill ing material and thethickness of steel tube can affect the weight of vehicle, the structure of bus body wasoptimized for lightweight in this paper based on the tube filling method. The uniformdesign method was used to set the experimental scheme on the side pillars and roofcrossbeams of bus body with different thicknesses of steel tube and lengths offillings in the tube. Meanwhile, a series of simulation studies on the bus rollovercrashworthiness were conducted. Based on the regression analysis of the simulationresults, the regression functions were established by SAS software and the designvariables were optimized by MATLAB software. The results show that, under thecondition of meeting the requirement of ECE R66for living space, the total weightof optimized side pillar and roof crossbeam structures was decreased by23.7%.3. Study on the occupant injury during bus rollover crash. The occupant injurycan be aggravated by the complex collision between occupant and occupant as wellas the contact between occupant and internal structures of bus during a rollover crash.Madymo was used to develop and simulate the bus rollover model. According to thecomparison between the MADYMO simulation result and the finite elementsimulation results, this MADYMO model can present the same deformation of bodystructure and collision acceleration as those in FE simulation. There, it can replacethe finite element method to analyze the rollover process. The Euro SID-I dummywas positioned at the impact side seat with the restraints of2-point belt,3-point seatbelt,4-point seat belt respectively to study the injury of occupant. Another EuroSID-I dummy was also added to study the influence of occupants interaction on theoccupant injury during bus rollover. The simulation results show that, although the deformation of bus body structures met the ECE R66, but some part of occupant canstill be injured. Besides that, the interaction of occupants during the rollover processcan cause more serious occupant injury.4. Study on the occupant injury based on the intrusive level of deformed upperstructure into the occupant survival space. Based on the original structure of busbody, five levels of the stiffness of bus body upper structure were increased whichmake the distance between deformed upper structure and occupant survival spaceincreased. Another five levels of stiffness of bus body structure were decreased toincrease the intrusion of upper structure into the occupant survival space. Moreover,one and two Euro SID-I dummy wearing2-point belt were simulated respectively toinvestigate the influence of different levels of the stiffness of upper structure on theoccupant injury. The results show that, whatever the deformation of upper structureis, the contact between occupant and side bus internal structure cannot be avoided.The increase of the stiffness of bus body upper structure can cause more seriousoccupant injury, but the decrease of the stiffness of bus body upper structure can alsocause severe compression to occupant. The best performance of occupant protectioncan be obtained when the deformation of bus body upper structure intrudes thesurvival space with a range that is between-20mm and+20mm displacement relativeto the location that the intrusion just reaches the survival space required in theregulation.5. Study on occupant injury under the condition that the side window is broken.Considering that the side window is usually broken during a rollover crash, o ne ortwo Euro SID-I dummy wearing2-point belt were simulated to study their injuryresponses. The simulation results show that the head and neck injuries can beaggravated under the condition that the side window is opened or broken. Therefore,the best protection performance for occupant can be obtained when the bus windowglass is unbroken.更多还原