MSC.Software机构控制一体化仿真整体解决方案

一、前言 在传统产品研发流程中,三维CAD、有限元分析、机构动力学分析和控制系统分析等环节相对独立,缺乏整体协同作业规划.机械工程师与控制工程师往往分别建模、设计和测试,再进行集成.这种开发方式,一方面,由于设计阶段机械工程师与控制工程师缺乏互动,单独设计的机械系统与控制系统缺乏综合考量,影响了设计效果;另一方面,后期产品测试和验证经常与原始设计不符,一旦出现问题,必须回到各自的模型中进行修改,浪费人力、物力.     

大型有限元前处理软件ANSA

一、总体介绍 ANSA是世界领先的、功能强大的CAE应用软件包,由希腊BETA公司开发,目前在世界上的应用非常广泛.ANSA具有强大的有限元网格前处理功能,支持结构和流体网格.一般来说,CAE分析工程师将80%以上的时间用于建立和修改有限元模型,因此采用一个功能强大、方便灵活的有限元前、后处理工具,对于提高有限元分析的质量和效率具有十分重要的意义.     

固体燃料冲压增程炮弹瞬态结构完整性分析

研究固体燃料冲压增程炮弹发射瞬态高过载下的结构完整性,结构强度优化是保证完整性的前提.为获取炮弹在发射过程中的瞬态结构强度,应用有限元软件对冲压增程炮弹发射瞬态的结构动力学特性进行了研究.建立了冲压增程炮弹的三维模型,采用有限元软件和瞬态动力学模型对冲压增程炮弹发射瞬态结构强度进行数值计算,计算结果验证了数值计算方法的有效性,冲压增程炮弹在发射高过载下的结构完整性良好,但在应力集中较大的部位仍然需要强化设计,结果对固体燃料冲压增程炮弹的设计具有重要的参考价值.     

JSTAMP/NV自动报告书功能详解及其应用

为使冲压仿真工程师高效地整理仿真结果并生成仿真报告,介绍JSTAMP/NV软件的自动报告书功能及其操作流程;以自动生成汽车翼子板的拉深工序的仿真报告为例,详细说明JSTAMP/NV自动报告书功能的使用.该功能可显著减少制作仿真报告的工作量.     

JSTAMP/NV中提升仿真计算效率的策略

针对仿真计算速度已成为制约冲压产品开发工程师和模具设计工程师工作效率提高的重要因素的问题,详细介绍影响JSTAMP/NV仿真计算速度的重要因素,在满足不同仿真需求的情况下推荐使用合适的仿真参数以合理利用计算资源;介绍JSTAMP/NV中一些特殊功能以进一步提升仿真计算速度.     

NIKE3D程序在板金冲压成形数值模拟中的应用

NIKE3D有限元分析程序可用于分析大变形和材料非线性问题，本文简要介绍了NIKE3D程序的主要功能和特点，应用该程序对几种板金冲压成形过程进行了数值模拟。     

基于Pro/MECHANICA的机床拖板有限元模态分析

本文介绍了基于Pro/MECHANICA的机床工作台拖板的有限元建模和分析过程,并将分析结果与常用的通用有限元分析软件ANSYS的分析结果进行了比较.通过比较得出结论:有限元工程师完全可以利用Pro/MECHANICA软件实现实体建模和有限元计算的无缝集成,并且能够保证有限元分析的计算精度,提高设计工程师的工作效率.     

汽车钣金冲压模具的验收

中国汽车行业迅猛发展，在这个过程中汽车覆盖件、底盘件、骨架件等大部分零件都采用冷冲压成形的工艺。目前大部分工厂模具验收的工作主要依靠模具或冲压工艺工程师的经验来进行，缺乏理论上系统而全面的指导，因此总结整理编制系统的冲压模具编制规范指导就显得尤为重要。
　　本文主要以冷冲压模具验收内容为基点结合实际验收经验，详细描述冲压模具验收过程。通常冲压模具的验收分为两个阶段：一、静态检查，模具未安装到压力机的情况下，在非工作状态进行的相关检查。二、动态检查，模具安装到压力机情况下，工作状态进行的各项相关检查。     

覆盖件成形缺陷的数值仿真实例分析

为研究汽车大型覆盖件成形规律,并分析其缺陷成因,介绍了板料成形动态显式有限元数值仿真技术的应用现状、基本理论及应用步骤.通过实例研究了采用有限无数值仿真技术进行覆盖件成形缺陷成因仿真分析的途径.仿真结果表明,采用数值仿真可以分析覆盖件变形规律,了解冲压过程中应力、应变分布及方向,成形极限图分布及缺陷情况,进而改进模具结构和冲压工艺,消除成形缺陷、提高产品质量.数值仿真技术是解决大型汽车覆盖件成形缺陷问题的有效工具.     

工程师的便捷分析工具

最新的CAE软件,最新的CAE技术,纷纷在中国这片肥沃的土壤里生根发芽.然而,由于种种原因,CAE技术在中国的应用并不广泛,工程与技术相糅合的CAE技术型人才更显缺乏.一直以来,我理想中的CAE工程师,首先力学基本功要扎实,对于有限元分析的每一个环节、影响因素都有大致直观的掌握,材料力学、弹性力学、塑性力学和结构动力学不能说精通,但是用到之时能够知道去翻阅哪本资料.     

Expert system for simulation of metal sheet stamping

Stamping processes are frequently used in the automotive industry. In an attempt to reduce developing times and costs, conventional design and manufacturing procedures are being changed. Finite element simulations have proved to be a good help in the design and analysis of these processes. The main problem of these simulations is that they are quite difficult to perform and that there are several non-trivial questions that the user has to answer before achieving a good model. In this work, a new application has been designed. It combines the usability of a custom application with the power of such a tool as the finite element method. To design this application, a lot of questions regarding FEM simulation of stamping processes have been analyzed. The result is a methodology to automate simulations of stamping processes where the user does not need to have deep knowledge of the finite element software. Such methodology has been successfully employed in a Spanish manufacturing industry of automotive components.     

PLASHTRAN: An expert consultant on two-dimensional finite element modeling techniques

An expert consultant and teaching aid has been developed to aid users of the MSC/NASTRAN (MacNeal-Schwendler Corp, Los Angeles, CA, USA) finite element code in the modeling process with two-dimensional elements. Written in LISP and LOOPS, an object-oriented programming language, the system, known as PLASHTRAN, allows engineers to work in a natural environment to obtain modeling recommendations. The program performs efficiently, especially when iterations in design require changes in the finite element model. The easily expandable modeling framework allows the knowledge base to incorporate new information.     

Proactive search enabled context-sensitive knowledge supply situated in computer-aided engineering

Processing complex and non-routine tasks, engineers face frequent knowledge shortage. While an expert system requires much effort to develop and a general search engine is blamed for passiveness in meeting people’s knowledge demand, we propose in this paper a context-sensitive knowledge supply method which aims at meeting users’ unuttered knowledge need bred in computer-aided engineering (CAE) tasks. To this end, concepts involved in a task are extracted and used for perceiving various problematic situations which may occur; and keyword-based search and text parsing techniques are combined to retrieve possible remedies from unstructured knowledge carriers. The proposed method is tested in situation of finite element analysis (FEA), a typical CAE task, where novice engineers receive sentential knowledge recommendations extracted from webpage. Experiment results show that context-sensitive knowledge supply can increase an engineer’s knowledge about the current task and make the individual more prepared for future challenges.     

Computer-aided engineering for sheet metal forming: definition of a springback quality function

Computer-aided engineering methods are extensively applied to sheet metal forming integrated design. The adoption of a new class of materials, the advanced high strength steels, has increased the occurrence of springback, and consequently the request for tools oriented to springback reduction and optimization. This paper presents an approximated formulation to compute the springback field after stamping through the finite element analysis of the process. This can be found assuming that the residual field of nodal forces after stamping produces a springback shape referable to a linear combination of n modes of vibration of the nominal shape of the component. The aim of this formulation is not that of substituting the finite element analysis of the springback but rather to make use of the coefficients of the linear combination, so to define a global quality function for springback. In this way, Robust Design methods or other current optimization procedures to improve the stamping process as for structural defects (such wrinkling, necking and flatness) can be applied also for the reduction of springback. The meaning of these coefficients will be shown through three test cases and the consistency of the formulation will be discussed according to the number of modes of vibration included in the computation.     

铁路货车轴箱密封窗骨架冲压工艺优化

以某铁路货车轴箱密封窗骨架为研究对象,针对其在冲压生产时翻边的圆角区域容易产生破裂的问题,基于手册资料进行初步分析,采用有限元法着重对展开进行数值模拟,得出合理的展开形状并制定冲压工艺方案.     

冲压成形残余效应对刚度分析的影响

针对冲压产生的板料厚度变化和残余应力等对有限元分析产生较大影响的问题,将冲压成形分析的网格节点厚度和塑性应变量等信息映射到车门总成刚度分析模型中,用MD Nastran分析车门刚度,并比较映射前、后车门刚度分析结果.结果表明在车门、内外板冲压成形残余效应影响下,车门总成刚度变化基本与料厚变化相吻合.     

钢结构货架计算分析系统CAD/CAE集成研究

随着计算机技术的飞速发展,有限元软件在结构分析领域得到了广泛的应用。但因其需要掌握的专业基础知识深,操作流程复杂而很难被普通的货架设计人员在短时期掌握。以数据文件为接口,利用VB进行编程调用有限元软件SAP84的计算模块进行二次开发,实现了钢结构货架通用计算分析系统（简称ASSRS系统）。此系统具有友好、方便、易用的人机交互界面 为钢结构货架的合理设计提供了帮助。     

Practical Application of the Stochastic Finite Element Method

The stochastic finite element method is an extension of the FEM that considers the uncertainty of a system that arises through variations in initial conditions, materials or geometry. Systems which display a measurable degree of disorder can be studied efficiently using a probabilistic approach. Different scenarios can be randomly generated with the SFEM to study the behaviour of systems that take into account prior knowledge of the differing variations in properties. This review paper introduces the most commonly used techniques: direct Monte Carlo simulation, the perturbation method and the spectral stochastic finite element method. It then looks at the currently available software for the SFEM and provides examples from the disciplines of materials science, biomechanics and engineering to illustrate different procedures by which the SFEM is practically used. The aim of the paper is to help scientists and engineers quickly assess how they might apply SFEM to their own research and guide them towards key publications.     

基于 h 型自适应有限元法在薄板冲压 成型中的应用

在对薄板冲压成型这一过程进行有限元仿真分析时,难以精确分析场变量发生剧烈变化的应力 集中及应变梯度大的区域,如何平衡精度和效率间的关系是冲压成型仿真的关键。因此,基于非线性有限元大 变形的相关理论,针对动态仿真的网格自适应关键技术,建立了自适应分析模式下的薄板冲压成型算法。为了 提高计算精度,提出基于单元应变能增量的能量误差准则以及基于板料成型几何特征的几何误差准则,并结合 2 类误差准则,建立了基于自适应分析算法的误差判断准则;为了提高计算效率,引入阻尼因子提出了阻尼子 循环算法,将自适应加密后的板料单元按时间步长划分为若干个区域,并按照不同时间步长分别求解。结果表 明,该算法有效提高了薄板冲压成型有限元仿真的精度与效率。