【作者】 刘维海；

【导师】 程秀生；

【作者基本信息】 吉林大学 ， 车辆工程， 2012， 博士

【摘要】 汽车安全问题一直伴随着汽车工业的发展，并且是各国政府、社会以及各大汽车制造厂关注的焦点之一。为保障交通事故中的人员安全、提高汽车的被动安全性能，各国政府和行业组织制定了严格的汽车安全法规与评价体系。这些法规和评价体系不仅是检验、评价汽车被动安全性能的重要依据，而且为汽车被动安全设计提供了研究方向。正面碰撞作为汽车交通事故和法规评价中的主要碰撞形式，已经成为轿车被动安全性设计的重要目标之一。另外，在碰撞事故中汽车对行人的保护性能越来越受到政府、企业和社会的关注，在汽车前端结构抗撞性设计中兼顾行人保护设计已经成为正面碰撞被动安全性能设计的新趋势。本文从整车正面碰撞被动安全性出发，对汽车正面结构抗撞性设计、乘员约束系统匹配优化以及对行人小腿保护性能等方面进行了较深入的研究。本文主要研究内容如下：①根据正面碰撞汽车-乘员动力学模型分析车体结构、乘员约束系统的主要参数与乘员胸部伤害响应的内在关系。对乘员胸部伤害关于碰撞加速度水平、车体结构最大动态变形、乘员约束系统固有频率和松弛量等主要参数进行敏感度分析；②建立正面碰撞仿真模型进行乘员主要伤害响应关于双阶加速度特征参数敏感性分析，将双阶加速度波形应用到正面抗撞性目标定义的工程实践中。以能量管理方法为基础提出基于平均压溃力的前端主要吸能部件优化设计方法，并运用该方法对某国产C轿车前部结构进行正面抗撞性优化设计及整车试验验证。同时，对该轿车在正面64km/h40%偏置碰撞中的乘员舱侵入现象进行了改进设计与整车试验验证；③在某国产轿车第一轮车体结构正面抗撞性整车试验中借用同级别轿车正面安全气囊和安全带部件，并以此缩小约束系统仿真优化参数范围。建立正面乘员约束系统仿真模型，并进行部件试验、台车试验验证，然后采用分步正交试验设计方法对正面乘员约束系统进行优化设计和试验验证。依据中国新车评价体系（C-NCAP）和欧洲新车评价体系（Euro-NCAP）评价某国产轿车正面成年乘员保护性；④详细分析汽车前部造型、空间布置、前端结构参数以及刚度特性等对行人小腿保护的影响。结合某国产轿车被动安全开发，应用多刚体和有限元耦合计算的方法对汽车前端结构进行改进设计，提高行人小腿保护性能。本文的主要创新点如下：①提出基于平均压溃力的前端主要吸能部件优化设计方法，利用该方法可以提高汽车前部结构正面抗撞性仿真优化设计的效率和精度；②在正面抗撞性整车验证试验中借用同级别轿车正面安全气囊和安全带的方法，缩小正面约束系统仿真优化的参数数量和范围；③采用分步正交试验设计方法对正面乘员约束系统进行优化设计，提高优化精度和可控性；④应用多刚体软件和有限元软件耦合计算的方法对某国产轿车前端结构改进设计，提高行人小腿保护性能。本论文所研究的项目为国内首次自主开发Euro-NCAP(2012)5星安全性能的轿车平台。通过参与该轿车正面碰撞被动安全性开发和控制的全过程，形成了高安全性能汽车的前部结构抗撞性设计、正面乘员约束系统匹配和行人小腿保护性能的一般性控制方法，为实现汽车正面碰撞被动安全性能的综合控制提供了切实可行的方法和理论依据。本论文研究内容及结果，对开发安全性能可获得Euro-NCAP5星级评价的自主品牌汽车具有一定的理论与实际意义。更多还原

【Abstract】 Automotive safety issues have been accompanied by the development of automobileindustry, and have been the focus of governments, society and major manufacturers. Toprotect persons in traffic accidents and enhance the vehicle’s passive safety, governments andorganizations have developed rigorous safety regulations and protocols, which are not onlythe basis for testing and evaluating automotive passive safety, but also specify the direction ofpassive safety design. Frontal crash is a major impact mode in real traffic accident and passivesafety regulation, so the frontal crashworthiness is one of the essential design targets forvehicle passive safety. In addition, pedestrian protection has gotten more and more concernsof governments, manufacturers and society, considering pedestrian protection in the design offront structure has become a new trend for frontal passive safety design. On the basis offrontal passive safety development, the frontal structure crashworthiness design, occupantrestraint system matching and pedestrian lower leg protection were studied in-depth. Thecontent in this paper are as follows:①On the basis of the vehicle-occupant kinetic model, The intrinsic relationship andinfluence of occupant restraint system parameters on the occupants injuries were analyzed.Using MATLAB software, sensitivity analysis of occupant injury response on the accelerationlevel, the maximum dynamic deformation, natural frequency and slack of restraint systemwere discussed.②According to the vehicle-occupant mathematic model, sensitivity analysis of dummyinjuries on the two stage acceleration characteristic parameters were analyzed, then themethod was applied to define the front crashworthiness objective in practice. In view of theenergy management, the method of vehicle frontal structure optimization was proposed basedon average crushing force sustained by main energy-absorbing component in frontal crash,which was successfully applied on the frontal structure crashworthiness optimization of adomestic sedan and validated by full vehicle impact test. At the same time, improvements forthe intrusion of the compartment in the mode of64km/h40%Offset Deformable Barrierimpact was fulfilled then were also validated effective by full vehicle impact test.③To mount other vehicle frontal airbags and seat belts in the vehicle used to verify thefrontal structure crashworthiness in a domestic sedan passive safety development process,which reduced the number and scope of parameters for the restraint system optimization. Thesimulation model of occupant restraint system was created, which validated by componenttest and sled test. Two step DOE method was created to optimize occupant restraint systemand validation tests were fulfilled. A domestic sedan adult occupant protection was evaluated based on the C-NCAP (2010) and the Euro-NCAP (2012).④The affects of the front of the shape, spatial arrangement, the front-end structuralparameters and stiffness characteristics on the pedestrian lower leg protection were discussedin details. Combined with the passive safety development of a domestic sedan, applyingmulti-rigid body and finite element coupling calculation improved the pedestrian lower legprotection performance.The innovations in this paper are as follows①The method of vehicle frontal structure optimization was proposed based on averagecrushing force sustained by main energy-absorbing components in frontal crash, which couldimprove efficiency and accuracy of the frontal structure crashworthiness simulation.②To mount other vehicle frontal airbags and seat belts in the vehicle used to verify thefrontal structure crashworthiness in a domestic sedan passive safety development process,which reduced the number and scope of parameters for the restraint system simulation.③Two step DOE method was created to optimize occupant restraint system, whichenhanced the accuracy and control of optimization.④Multi-rigid body and finite element coupling calculation method was created toimprove the pedestrian lower leg protection.The research project covered in the paper was a domestic self-developed platform aimedat Euro-NCAP (2012)5-star rating for the first time. Through the development process ofpassive safety, the general control method of front structure design, restraint system matchingand pedestrian lower leg protection were initially formed to meet the Euro-NCAP (2012),which provided a feasible thesis basis and control methods for car passive safety. Theachievements in the paper had some theoretical and practical significance for self-brandvehicles to get Euro-NCAP5-star rating.更多还原