车身覆盖件冲压成形动态仿真的几何建模技术

本文介绍了车身覆盖件冲压成形动态仿真中的几何建模技术和建模过程中所使用的造型方法。指出了车身覆盖件产品模型与冲压拉延模模型之间的区别;分析了拉延模型面造型与仿真模型的关系以及拉延模造型对仿真计算结果的影响;另外从ＣＡＤ模型数据交换角度出发,说明了数据转换在建模技术中也起着非常重要的作用,同时介绍了三种常用的数据交换标准。最后给出了桑塔纳２０００型轿车前门外板凸模的造型。     

汽车车身覆盖件的工艺分析方法

阐述了车身覆盖件工艺分析方法,对分析过程中应注意的问题和重点作了说明。     

车身装配虚拟样机建模研究

传统的车身装配设计需要多轮实物试制,增加了周期和费用,为此提出了支持虚拟样机技术的车身装配集成建模框架。该集成框架分为基于焊装特征的装配建模、偏差传递计算模型和装配环境仿真模型等三个子模型,并以产品数据管理为平台,通过接口方式实现了各子模型中装配数据和过程信息的协调管理。最后给出了一个某实际车身前地板装配设计的实例。初步实践认为,该集成框架可对缩短装配开发周期、降低车身试制费用提供有效支持。     

车身覆盖件虚拟制造系统的开发与研究

介绍了利用通用机械ＣＡＤ软件ＣＡＤＤＳ５和非线性有限元分析程序ＤＹＮＡ３Ｄ进行ＣＡＤ／ＣＡＥ／ＣＡＭ一体化的车身覆盖件虚拟制造系统的开发与研究，给出了车身前翼子板的曲面造型、模具实体生成、成形过程模拟分析及数控加工过程仿真实例，该系统具有良好的应用前景。     

车身覆盖件冲压CAPP中面向对象的特征建模

介绍了在开发车身覆盖件冲压工艺ＣＡＰＰ系统过程中采用的面向对象的特征建模方法。文中描述了特征模型,特征环的组环算法以及对特征精度信息的表达方法等。     

车身覆盖件虚拟制造系统的开发与研究

介绍了利用通用机械ＣＡＤ软件的ＣＡＤＤＳ５和非线性有限元分析程序ＤＹＮＡ３Ｄ进行ＣＡＤ／ＣＡＥ．ＣＡＭ一体化的车身覆盖件虚拟制造系统的开发与研究，给出了车身翼 子板的贡面造型、模具实体生成、成形过程模拟分析及数控加工过程仿真实例，该系统具有良好的应用前景．     

车身覆盖件模具数字化制造技术

根据车身覆盖件的产品特点，进行工艺补充面、压料面、拉延筋、凹模圆角的设计，得到完整的三维工艺数模；对车身覆盖件进行拉延成形数值模拟，通过板料成形极限图、厚度分布图、应力应变分布图，保证覆盖件的工艺数模具有良好的成形性能；根据验证的工艺数模，进行模具三维结构设计和数控加工；对覆盖件模具进行了CAD／CAE／CAM一体化集成。     

浅谈车身覆盖件表面质量的控制

轿车车身覆盖件的表面质量指的是覆盖件外表面的外观质量,它虽然不影响整车的使用性能,但却直接影响整车的外观,在当今的轿车生产中是影响整车质量的一个重要因素。 1.覆盖件常见的表面质量缺陷及产生原因 在覆盖件的冲压生产过程中经常发生的表面质量缺陷有暗坑、波浪、棱线不清晰和拉毛、压痕、麻点及磕碰、划伤等。这些缺陷的实质是对覆盖件     

汽车车身覆盖件成型缺陷研究与应用

车身覆盖件是汽车的重要组成部分,其表面质量直接影响了整车的外观品质,一定程度上代表着汽车企业的工艺及制造水平。文章以福汽启腾MPV车型顶盖外板为例阐述车身覆盖件成型缺陷产生原因,对CAE工艺分析、模具制造、调试等阶段的成型缺陷进行分析研究,从理论到实际介绍车身覆盖件成型开裂、起皱、回弹等缺陷的解决方案。     

点焊接头设计对车身质量的影响

基于有限元分析方法,探讨了点焊三种接头形式对车身力学性能和尺寸精度的影响,指出了车身点焊要用不同的接头形式时应重点考虑的问题。     

Laser dimpling and remote welding of zinc-coated steels for automotive applications

The flexibility in terms of beam shapebility and amplitude in the range of process parameters offered by the emerging high power and quality active fiber lasers can be advantageously used in overcoming the well-known problems in remote laser welding of zinc-coated steel components in the car mass production. The paper explores the potentiality offered by the combination of the scanner technology with high brilliance fiber lasers when laser dimpling and remote welding are executed in a successive order: the first one to realize gap spacers and the second one to weld together clamped sheets in zinc-coated steels. In particular, the substitution of the traditional mechanical dimpling with the laser dimpling is investigated in order to highlight the potentiality of a solution that is flexible, unaffected by tool wear and highly productive.     

Mode I failure modeling of friction stir welding joints

This paper analyzes mechanical response by finite element method up to the decohesion failure in fracture mode I for joints of friction stir welding (FSW) of an aluminum alloy. It first describes experimental investigations on specimens with FSW embedded, subjected to uniform traction and local punch tests used to characterize local elastic and plastic material parameters. The heterogeneity of the mechanical properties induced by the FSW process is taken into account for the elastic-plastic finite element simulation. The growing damage and the opening failure of the welding zone are described by the adoption of a cohesive interface model with specific mechanical properties.     

点焊连接的有限元建模方法研究及案例应用

建立一种高精度和高效率的点焊连接有限元模型可以提高点焊结构的有限元分析精度。通过焊接钢板的试验模态与计算模态的对比分析,探讨并评价了4类焊点模型的模拟精度、建模优劣和建模时间,确定了ACM2模型和CWELD/ELPAT模型为薄板点焊连接有限元分析中的较优选择。利用HyperMesh、Nastran软件联合仿真,对某电动汽车电池包进行了模态分析和台架定频振动试验工况的模拟,结合试验结果,进一步评估了两种焊点模型的模拟精度和模型计算速度。结果表明,CWELD/ELPAT模型能准确模拟焊点位置、模拟精度高、建模时间短且模型计算速度快,适用于模拟电池包的点焊连接,为解决电池包因焊点数量多、焊点附近局部网格不协调、结点不对齐导致的点焊建模难点提供了参考,为电池包的有限元分析提供了有力支持,具有较好的工程意义。     

FE analysis of unstiffened and stiffened corrugated panels subjected to blast loading

This paper presents the results of a dynamic analysis on unstiffened and stiffened corrugated panels subjected to hydrocarbon explosion. A parametric study is also conducted on simplified models of the stiffened corrugated panels considering the effect of stiffeners on the compressive flange under different loading levels. The 1/2 symmetry of corrugated panels is modeled. This numerical study is performed using NX Nastran version 7.5. The unstiffened panel produces localized buckling at the center of corrugation and large permanent deformation by increasing the peak pressure. The stiffened panels suppress the structural response, and the vee stiffeners are structurally more effective than the round ones.     

汽车覆盖件冲压方向的优化分析

汽车覆盖件具有尺寸大、形状复杂、板材薄等特点,在冲压成型的施工过程中对于冲压方向以及精度的要求十分严格,冲压方向的选择一旦出现失误,不仅会影响覆盖件冲压成型的质量而且还会延误工期以及资源浪费等负面影响。因此本文对汽车覆盖冲压方向的优化进行分析。     

Mechanical properties of graphite/aluminum metal matrix composite joints by friction stir spot welding

Graphite/aluminum metal matrix composite (MMC) joints are successfully fabricated by friction stir spot welding (FSSW). During lap-joining processes of aluminum alloy sheets by FSSW, graphite/water colloid is applied between the tool shoulder and the upper plate. The Raman spectrum of the FSSW joint confirms that graphite/aluminum MMC is successfully induced in the stir zone. Quasi-static shear tests and micro hardness measurements of the FSSW joint also show that the strength and toughness of the joint are significantly improved by inducing graphite/aluminum MMC in the stir zone. The results of the present study suggest that the mechanical properties of structural components joined by spot welds can be easily enhanced by adopting MMC joints by FSSW, instead of changing the material or increasing the number of joints.     

焊接参数变化对点焊质量的影响

低碳钢点焊U-I图主要有三种类型:椭圆型、双头型、多头型.未发生飞溅时呈现椭圆状,在发生飞溅时呈现双头或多头状,此外基于点焊质量检测研究的点焊u-I图反映焊接过程动特征的特征信息,可为低碳钢焊接参数的优化提供依据.