汽车钣金结构有限元分析的精度

通过非线性CAE分析软件Abaqus实现钣金结构的冲压和回弹过程,并将冲压结果映射到舱盖总成结构.考虑料厚减薄和残余应力对舱盖振动特性的影响,为提高分析精度提供参考.     

汽车车门内板冲压成形工艺分析

该文分析了某轿车车门内板的成形工艺及易产生的缺陷。并据此制定了合理的冲压工艺方案。文章通过对拉延成形过程的模拟与分析,得出了合理的工艺方案,目的是为类似零件工艺方案的制定提供参考。     

车门铰链系统与车门下沉刚度的相关性

针对某型车门下沉问题,通过台架试验获得车门、铰链和车身等各单因素下沉量和车门绞链系统整体下沉量,对单因素下沉量与系统整体下沉刚度进行线性拟合分析,得到车门铰链系统各单因素与系统下沉刚度的相关度排序.对前、后车门分别选取相关度较高的单因素进行优化,最终改进方案的仿真和试验结果证明该方案可有效地提升车门下沉刚度.采用定量分析法可快速找出影响下沉刚度的敏感因素,并能够快速生成优化方案,为新车型设计提供参考.     

大型厚壁半球形封头热冲压成形的数值模拟

该文利用SuperForm软件，对带直边大型厚壁半球形封头的热冲压成形过程进行了有限元数值模拟。分析了厚壁半球形封头热冲压成形过程的变形特点及坯料与模具间摩擦系数、下模形状、温度等因素对封头成形后壁厚变化的影响。     

基于实体单元的薄板成形模拟

传统有限元分析薄板成形一般使用壳单元进行模拟,忽略薄板沿厚度方向应力应变的变化,这很难反映薄板弯曲变形部分的状况.基于连续介质力学及有限变形理论,借助于计算机仿真技术,利用LS-DYNA软件中的实体单元模拟了低碳钢板深冲成筒形件的过程,得到了薄板在冲压成形过程中的应力应变场,并分析了板料各区域的受力变形情况,发现了凸凹模圆角处薄板沿厚度方向的应力应变分布并不均匀,这些模拟结果对筒形工件的深冲压加工具有一定的指导意义.     

乘用车车门刚度提升方案

用MSC Nastran对乘用车车门刚度提升方案进行研究,得到提升车门各方向刚度具体方案的实施效果.结果表明该实施方案可以有效提升车门刚度.     

基于JSTAMP/NV的冲压模具变形分析

随着高强度钢在汽车车身上的广泛应用,冲压模具结构变形问题也日益突出.采用JSTAMP/NV和HyperMesh,对冲压成形和模具结构进行解耦有限元分析,研究模具各部件在成形过程中的应力分布规律和变形结果.结果表明：最大等效应力发生在曲率比较大的区域,而且不一定发生在模具的最终闭合阶段.该分析结果为优化模具结构设计和模具疲劳校核提供参考.在冲压成形仿真过程考虑模具结构变形的影响,结果显示模具结构的变形对材料的流入有很大影响,最终影响制品的成形精度.     

板料多次拉深成形仿真过程关键技术研究

计算机仿真技术作为板料冲压成形的辅助工具，能够动态地反映板料与模具之间的相互作用以及板料实际变形全过程中的应力、应变及厚度变化及分布。文章针对多次拉深成形的特点和难点，分析了多次拉深成形计算机仿真的一般过程，阐述了多次拉深成形仿真过程中应注意的几个关键技术问题：几何模型的建立、网格划分、屈服准则的选用、板料与模具间干涉问题的处理以及工序间变形历史信息的传递等。文章所阐述的关键技术对于多次拉深这一比较复杂的板料成形仿真应用、研究有较大的参考作用。     

板料冲压的数值成形实现

一、前言 冲压成形过程包含十分复杂的物理现象,冲压成形技术由压力机械、冲压模具,冲压工艺,材料及润滑技术和生产自动化技术等重要环节组成。冲压模具和冲压工艺技术是其中最关键的技术,也是板料冲压成形中的难点。对一个给定的零件来说,一套合理的模具和工艺方案的确定,传统方法不仅要靠实践经验和理论计算,还往往离不开反复的试模和修模。由于塑性成形过程的影响因素非常复杂而且涉及到非线性问题的求解,靠人为经验准确制     

汽车车门过开启有限元分析

用Abaqus中的静力学分析功能,对某款车型前门进行过开启分析,得到此车门的过开角度和卸载后车门的残余角度以及车门和限位器的受力状况.同时,利用Abaqus中的MODEL CHANGE关键词,实现车门在过开启后,只有车门重新关闭而限位器保持不动的模拟,以此来考察车门能否关闭,从而更进一步评估传统的车门过开启分析方法.仿真结果表明:该车门过开性能满足设计目标,无破坏风险,且MODEL CHANGE关键词可以为模拟车门的关闭提供极大方便.     

基于多工况的车门结构多目标优化设计方法研究

车门结构的单一工况优化设计常难以满足车门设计要求。本文基于车门垂直刚度和一阶模态两工况,提出一种车门结构多工况多目标优化设计方法。以车门垂直刚度、一阶频率和车门质量为优化目标,通过均匀拉丁方试验设计和响应面方法得出车门垂直刚度和一阶频率的近似数学模型,并在此基础构建车门结构多目标优化模型。最后采用多目标遗传算法对其进行求解,最终优化结果在车门质量减少的情况下,垂直刚度和一阶频率均达到设计要求,达到预期优化效果。     

基于MSC Nastran及整车模型的动力总成悬置解耦分析和优化方法

基于六自由度刚体 悬置模型的动力总成悬置解耦分析和优化方法通常是在概念设计阶段,缺乏整车模型数据时的一种初步设计方法,由于未考虑车身刚度和质量的影响,难以反映实车状态下的真实解耦情况.为此,提出一种基于MSC Nastran及整车有限元模型的动力总成悬置解耦分析和优化的新方法,并验证该方法的正确性、可行性和有效性.     

Integrated metal forming and vibration analysis of sheet metal parts

Modern software programs are routinely used by industries to study the characteristics of and to reduce the cost of sheet metal parts that are used in automotive and other applications. Virtual simulations that are based on complex math models and state-of-the-art computational tools play a very important role in reducing the high costs associated with prototypes and the time to market the product. Formability studies of a sheet metal part determine if a part is formable by changing the factors that affect its formability. Vibration (or modal) analysis is performed to determine the frequency and mode shapes of the component or the assemblies. A gauge optimization study is performed to determine the optimum gage thickness assigned to components of an assembly while constraining the frequency of specified modes to a desired level. Usually these studies are done separately by different engineering departments in a typical automotive industry. In this paper, a single component from an instrument panel (IP) reinforcement assembly is analyzed by integrating the three different studies mentioned above. It was found that the thickness of the bracket and the coefficient of friction in the stamping process should be kept as low as possible to reduce the chance of splits occurring in the bracket. An optimum thickness for the same bracket as part of an assembly can also be determined using a gauge optimization study so that the assembly was stiff enough while minimizing its mass. Thus, an integrated analysis using simulation tools helps in better design of the parts and subassemblies, which ultimately helps stay in competition to produce quality products.     

汽车侧面碰撞CAE对标分析

为提高整车碰撞安全性能,针对LINCAP工况,将某新车型整车侧面碰撞CAE仿真与试验结果进行对标分析,通过对比可变形壁障及车身侧变形模式、车门变形轮廓曲线、关键点侵入速度等校对有限元模型,验证该侧面碰撞仿真模型的精度和建模方法的有效性.该对标分析可为新车型碰撞安全性能开发的CAE分析提供参考.     

车门不平整度对橡胶密封性能的影响

为研究车门不平整度对车辆密封性能的影响,提出一种“钢条 硬橡胶 软橡胶”类密封条分段建模与不平整度模拟的方法。以某型车辆驾驶室车门结构为例,考察车门顶端和局部凹坑不平整度对密封性能的影响。计算结果表明这种建模与分析方法可靠,可高效地模拟车门与橡胶密封条变形前、后的接触状态和接触应力,以及由于局部缺陷引起的不平整度对密封性能的影响。     

汽车轻量化冲压技术及其数值模拟

简述汽车轻量化技术的途径和基于JSTAMP／NV的仿真流程,针对目前汽车轻量化采用的激光拼焊、液压成型和热冲压成型等3种主要的先进加工制造技术,以车门内板、副车架和汽车B柱典型零件为实例说明JSTAMP／NV数值模拟的应用．应用板料冲压成型数值模拟技术是快速实现汽车轻量化冲压技术有效应用的重要途径．     

Partitioning design space for linear tuning of natural frequencies in planar dynamic MEMS structures

One of the critical design considerations in dynamic microelectromechanical systems (MEMS) devices is the structural natural frequency of the sensing or actuation element. Most dynamic MEMS devices employ planar geometry using an assembly of beams and plates for the structural elements. Most often the goal is to place the first resonant frequency at a desired value. Since the frequency depends on mass and stiffness of the structure, designing for frequency usually requires FEM analysis of the structure. FEM calculations are intensive, depend on many subtle modelling assumptions, and require huge number of simulations to build intuition. Since the design space for such structures is fairly high dimensional, tuning the frequency of the first-cut design can be a fairly intensive optimization computation. Here, we present a lumped parameter spring-mass model for a typical microstructure consisting of a plate and beams and show how the higher dimensional geometric design space can be partitioned to effect desired frequency changes in the structure linearly with the chosen design variables. In particular, four sets of design variables are considered and their effective range and sensitivity for linear tuning of the natural frequency is presented. We include the effect of residual stress on stiffness and show how the values of residual stress affect the tuning of the natural frequency with respect to the selected design variables. All results are compared with FEM calculations and a table is presented for cross comparison of efficacy of the different design variables. The goal is to present a simple analysis that can be easily followed by MEMS designers with any background and build their intuition for such designs.