基于C-IASI规程下台车侧面碰撞模拟试验方法研究

为了节约开发成本,减少实车碰撞试验次数,基于中国保险汽车安全指数(China Insurance Automotive Safety Index,C-IASI)中侧面碰撞试验规程,使用带有副台车的加速台车设备,通过主台车复现整车试验假人胸部中间肋骨位置对应车门内钣金Y方向加速度,副台车通过蜂窝铝调节复现车辆非被撞侧B柱Y方向加速度,以此实现台车侧碰模拟试验,并在某车型上进行验证。结果表明:SID-IIs假人躯干伤害与碰撞结果的接近度在90%以上,且仅一次即满足对标要求;基于加速台车和蜂窝铝调节开发的侧面台车试验方法,能够更好代替实车进行侧面约束系统开发试验。     

基于MADYMO模型的再次优化使达到 C-NCAP 4星的目标

为了达到某车C-NCAP 4星的目标,在基于台车试验数据、几何数据和约束系统零部件试验数据的基础上,建立了某车正面100%碰撞乘员约束系统的MADYMO模型,此模型可以很好的再现滑台试验,并在改变气囊和安全带参数上进行了优化,优化后假人伤害值达到了预期的分解目标,做滑台试验验证了MADYMO模型的准确性,第一次摸底试验副驾驶员侧假人头部及颈部伤害值未达到预期的分解目标。再次通过MADYMO优化副驾驶员侧气体发生器向安全气囊充气的性能(压力-时间曲线),使副驾驶员侧假人头部及颈部伤害值达到满分,第二次摸底试验结果达到了假人伤害值的分解目标。     

DOE在副驾驶员胸部伤害值分析中的应用

基于历年C-NCAP测试结果,假人胸部失分是车辆C-NCAP评价难以获得高分的主要障碍之一,因此,在车辆被动安全系统研发过程中应重点关注对假人胸部的保护。以副驾驶位假人胸部伤害值为研究对象,借助HyperStudy工具,使用DOE全因子法分析诸多因素对假人胸部伤害值的影响规律,并据此提出针对典型车型的一般被动安全约束系统配置,为被动安全约束系统开发积累经验,提高开发效率。     

基于模块化设计的正面碰撞车身加速度复现技术研究

基于模块化设计概念,研究了微型汽车车身加速度波形复现技术。论文对微型汽车平台衍生车型的正面碰撞车身加速度波形进行了等效简化,分析了关键结构吸能特性对车身加速度波形的影响;基于能量吸收和刚度等效,设计等效结构台车替代平台衍生车型研发过程中的骡子车,通过车身加速度波形验证试验表明台车设计方法可实现车身加速度的复现,该台车所测车身加速度波形满足乘员伤害相应模型仿真输入要求,有效提高了研发效率并降低了设计成本。     

汽车手刹及车身安装结构平台化设计研究

通过分析手刹及周边零部件的关键尺寸链,找到最小成本实现平台化的部件,并通过尺寸带宽与性能带宽的研究,固化手刹与地板的结构,从而实现手刹与车身地板安装结构的平台化,并在某平台车型开发中展开应用,实现了手刹安装结构与手刹的平台化,经过6款车型的开发验证,具有良好的零部件与结构的共用性及拓展性,加快了研发速度,保证了设计质量。     

车身焊装生产线柔性化改造的技术研究

介绍了不同车型车身焊装生产线柔性化改造的开发过程,阐述了在工装设计和工艺布置过程中的技术难点、要点的解决方法。在原生产线上通过柔性改造,加入加长车车型,成功实现短车、长车两种车型主线的共线生产。     

基于Radioss的整车64km/h正面偏置碰撞性能优化

所述车型64 km/h正面40%偏置碰撞性能优化是基于Altair公司的Radioss求解器,通过建立包含假人和约束系统的有限元整车碰撞模型不断计算和优化来达成。假人伤害值优化从单纯的滑台模拟的基础上引入了实时的加速度、前围板侵入、踏板侵入等边界条件。约束系统与整车结构耐撞性得以同步进行分析和优化。分析结果表明:经过多方向优化,达到了整车碰撞性能开发在详细设计阶段预定的目标。     

儿童乘员约束系统台车碰撞试验设计与研究

为满足GB 27887-2011规定的儿童乘员用约束系统动态性能试验的台车加速度区间要求,提出组合不同长度、壁厚、直径的圆形薄壁吸能管来实现台车碰撞试验波形的方法。采用LS-DYNA软件建立台车和吸能管的有限元模型,并通过该模型获得能复现法规要求的前后碰撞加速度区间的吸能管组合参数,经台车碰撞试验验证其有效性和精确性。对碰撞过程中Q6儿童假人头部和胸部动态响应进行了致伤机理分析,同时基于像素分析法提取了假人头部质心位置的运动轨迹,最后通过分析试验结果,对该新型儿童约束系统提出了改进意见。     

基于3DCS的白车身偏差分析

本文以某款车型白车身前端模块安装孔为载体,用三维偏差分析软件3DCS建立尺寸仿真模型,虚拟制造过程,识别影响目标尺寸公差的影响因素,并通过工装优化、提升零部件公差等优化方式,解决白车身前部尺寸偏差的难题。     

汽车正面碰撞乘员约束系统的安全性分析

根据正面碰撞乘员约束系统的结构,简要地介绍了某车型中乘员约束系统各部件的模型的建立。并对建立好的模型进行了仿真分析,假人的伤害情况结果表明,该车型的乘员约束系统对乘员起到了很好的保护作用。     

混Ⅲ假人、GHBMC人体模型以及中国人体模型的正碰损伤差异

基于清华大学汽车碰撞试验室关于中国参数化人体有限元模型的研究,根据中国50百分位人体的参数生成了可用于碰撞仿真的中国50百分位人体模型,通过相同车型同一工况下的碰撞仿真分析,使用损伤响应分析和损伤风险曲线两种不同的评价方式研究了Hybrid Ⅲ假人、GHBMC有限元人体模型以及中国50百分位人体模型损伤响应的差异性。结果表明,相比中国50百分位人体模型,Hybrid Ⅲ 50百分位假人模型的颈部和胸部损伤风险更高,而GHBMC 50百分位人体模型的大腿损伤风险更低,分析结果揭示了两种乘员评价工具在评价基于保护中国人体而设计的乘员约束系统时的差异性和局限性。     

A study on the design of a child seat system with mutipoint restraints to enhance safety

Currently, child seats are widely used as a child restraint system (CRS). The effects of CRS are experimentally investigated according to FMVSS213. In this paper, the dynamic simulation of a child seat is carried out using the LSDYNA software to develop an advanced CRS. A sled test using an existing child seat is first carried out, and the computer simulations using the LS-DYNA software are compared to the sled test to validate the dummy model and computer simulation. After matching the sled test and computer simulation results of a three-point belt-type child seat, a new type of child seat is developed with the computer simulation and optimization. For weight reduction, an optimization sequence is applied to determine the thickness of each part. For the area of stress concentration, reinforced members are added. The comparison between the simulation and the sled test shows good agreement, and the simulation results are proven useful for the further development of an advanced CRS.     

The effect of crash pulse on occupant injury in frontal coach collisions

The purpose of this study is to reveal the effect of different acceleration curves on occupant injury risk in the frontal collision of coaches. Based on characteristics of frontal crash acceleration curves, the influence of characteristic parameters on occupant injury was studied using a two-factor variance analysis method. The finite element-rigid body coupling method was used to establish a coupled simulation for the dummy and the sled and evaluate differences in the effects on occupant injury between the acceleration curves of four different coaches and the acceleration envelope of the ECE R80 standard. Results indicate that the upper limit of the simplified curve has the greatest influence on occupant injury and it displays a positive correlation. The acceleration curve stipulated by ECE R80 is too idealized, which may lead to inadequacies in safety protection capability in vehicle and seat design.

     

面向装配系统可靠性分析的车身夹具系统优化设计

为描述多工位车身装配系统的渐进衰退特性,建立了面向车身产品尺寸质量和夹具系统要素的装配系统可靠性模型。结合夹具设计稳定性参数约束,提出了面向白车身装配系统可靠性的车身多工位焊装过程的夹具布局优化方法;在给定夹具布局下构建了定位销制造成本函数,提出多工位夹具定位销磨损率的优化模型并对其进行优化分配。将上述方法应用于侧围装配案例,分析发现优化后装配系统可靠性衰退过程得到较大改善,并有效提升了夹具系统的使用寿命。     

基于正交试验设计的乘员约束系统性能优化

在微型轿车正面碰撞过程中,乘员容易受到严重伤害,优化乘员约束系统对于乘员的保护极其重要。利用MADYMO软件建立了包含座椅、安全带、仪表板及转向系统在内的某微型客车乘员约束系统的分析模型,并通过试验验证了模型的有效性。最后利用验证后的模型对约束系统的参数应用正交试验设计的方法进行优化,实现了对该车正面碰撞过程约束系统的较全面且较可靠的评价。     

硬同轴线系统装配过程优化

装配过程中出现的连接间隙、密封以及受力状况不佳等问题,直接影响了硬同轴线系统的工作性能。因此,解决硬同轴线系统装配过程中存在的问题,是保证其高可靠性的先决条件。文中通过剖析硬同轴系统的组成,分析故障原因,提出了硬同轴系统装配过程优化工艺方案。通过控制、检验同轴线间隙,划分安装段,设置测试点,监测入射与反射功率,确定补偿垫片尺寸以及安装前调试等手段,提高同轴线系统的工作性能。实践表明,这些方法具有较好的可操作性和较高的实用价值,优化了装配过程,提高了硬同轴线系统的可靠性。     

Design and optimization for the occupant restraint system of vehicle based on a single freedom model

Throughout the vehicle crash event, the interactions between vehicle, occupant, restraint system (VOR) are complicated and highly non-linear. CAE and physical tests are the most widely used in vehicle passive safety development, but they can only be done with the detailed 3D model or physical samples. Often some design errors and imperfections are difficult to correct at that time, and a large amount of time will be needed. A restraint system concept design approach which based on single-degree-of-freedom occupant-vehicle model (SDOF) is proposed in this paper. The interactions between the restraint system parameters and the occupant responses in a crash are studied from the view of mechanics and energy. The discrete input and the iterative algorithm method are applied to the SDOF model to get the occupant responses quickly for arbitrary excitations (impact pulse) by MATLAB. By studying the relationships between the ridedown efficiency, the restraint stiffness, and the occupant response, the design principle of the restraint stiffness aiming to reduce occupant injury level during conceptual design is represented. Higher ridedown efficiency means more occupant energy absorbed by the vehicle, but the research result shows that higher ridedown efficiency does not mean lower occupant injury level. A proper restraint system design principle depends on two aspects. On one hand,the restraint system should lead to as high ridedown efficiency as possible, and at the same time, the restraint system should maximize use of the survival space to reduce the occupant deceleration level. As an example, an optimization of a passenger vehicle restraint system is designed by the concept design method above, and the final results are validated by MADYMO, which is the most widely used software in restraint system design, and the sled test. Consequently, a guideline and method for the occupant restraint system concept design is established in this paper.