板料拉伸成形中确定合理毛坯形状的理论方法综述

合理的毛坯形状不仅可以提高原材料的利用率，减少成形后的修边余量，而且能改善可成形性，大大提高成形质量。对此，人们提出了许多预测方法和估算方法。本着重对各种确定毛坯外形的理论方法做原理上的介绍及比较，并讨论了有关方法中存在的问题和今后研究的方向。     

板料真实成形极限的测定及其应用

采用带圆弧侧边板料的单向拉伸试验方法及工具显微镜厚度测量法测定了St14铝镇静钢板向应变（ε2）较大的真实成形极限。并折算成ε2为0．4时的真成形极限的FLD－0．4，分析了FLD－0．4与常规单向拉伸试验性能的关系。     

板料高频感应热应力成形技术试验研究

文章在分析水火成形和激光热应力成形研究工作基础上,选择了钛板作为研究对象,使用自己设计的试验装置对高频感应热应力成形进行了试验研究,得到了感应加热工艺参数、冷却方式和材料性能等因素对板料弯曲变形的影响规律.结果表明:板料弯曲角度随着电流的增大或线圈移动速度的提高而先增后减;采用水冷方式能够比空冷方式获得更大的弯曲角度;板料弯曲角度随着电流频率的提高增大.     

板料拉延成形极限理论

提出板料拉延的失稳判据、成形极限曲线可根据拉伸试验数据绘出。计算结果和试验符合良好。     

板料成形CAE技术研究

以复杂异型拉伸件拉伸成形模拟为例,介绍板料成形CAE技术的方法、步骤和结果分析,并研究了压边力对板料厚度的影响规律.结果表明,压边力在15 kN时材料厚度变薄率最小.为进一步研究板料成形提供了帮助.     

板料成形中材料模型的研究进展

介绍了板料成形数值模拟中材料模型的研究进展。将材料模型的理论研究分为屈服准则、强化模型、流动法则、加卸载历史4个方面,并进行简要综述;对材料在循环加载条件下应力应变曲线的实验获取方法进行了探讨,重点介绍了板料压缩、三点弯曲实验确定材料反向加载应力应变曲线的原理和方法;对当前屈服准则、强化模型的研究热点和发展方向进行了分析。     

板料弯曲成形性能的有限元模拟研究

介绍了以Pro/E为模具结构设计平台,利用有限元动力分析软件ANSYS/LS-DYNA的前处理和求解模块对板料的弯曲成形过程进行数值模拟,分析了板料的弯曲性能,研究了弯曲半径对板料弯曲成形质量的影响,利用LS-PREPOST后处理器查看结果,得出应力应变曲线,为板料成形性能的检验提供了依据。     

网孔板渐进成形性能

采用单点连续渐进成形和点压渐进成形分别对网孔板进行定角度锥杯实验,实验结果显示单点连续渐进成形极限角为48°,大于点压渐进成形极限角为45°。采用这两种渐进成形方式,网孔板变形区域的圆孔均变成椭圆孔。通过测量这两种渐进成形42°定角度锥杯椭圆孔长轴尺寸,表明单点连续渐进成形网孔变形相对较小。采用动态有限元软件,模拟这两种渐进方式成形42°定角度锥杯过程,研究对比其应变、厚度及成形力的变化。模拟结果表明,点压渐进成形网孔板应变、厚度变化波动范围较小,成形力较单点连续渐进成形减小了44%,这两种渐进成形网孔板锥杯的椭圆孔短轴侧厚度较长轴侧厚度减小很多。     

板料点压渐进成形的成形性能研究

板料渐进成形技术作为柔性制造技术,其研究已经取得相当进展。但是在进给轨迹连续的普通渐进成形中,材料在成形过程容易产生沿轨迹方向的推挤,而产生不必要的变形,影响加工能力和加工质量。通过圆弧沟槽实验,对比点压渐进成形和连续渐进成形,发现点压渐进成形可获得的沟槽长度为60.5 mm,大于连续渐进成形中48.9 mm的沟槽长度;破裂位置最大主应变分别为1.212和0.982,说明板料点压渐进成形时的成形性能比连续渐进成形好。通过改变点压渐进成形中正弦波的波长和振幅,说明两参数对成形性能的影响。采用成形性能更好的点压渐进成形,可减少多道次渐进成形的成形道次,拓展渐进成形所能成形的零件结构类型。     

Key performance indicators for sheet metal forming processes

Sheet metal forming is a typical process in the manufacturing industry. It is well established, e.g. for the production of car body components or consumer goods. Suppliers of Original Equipment Manufacturers (OEM) produce a wide range of products in different dimensions, varying batch sizes and geometries. For the production process itself, there are multiple configurations regarding the selection of technologies, machines and tools to be used. In order to meet the market’s requirements and to be highly competitive, the complete process chain needs to be optimized. The main challenge for the optimization of the process chain is the simultaneous consideration of technical and organizational parameters. The relevant key performance indicators (KPIs) have to be identified and used to support the decision-making process for production planning purposes. In this article a method to identify the relevant KPI is described and relevant indicators were proposed.     

基于数码相机的板料应变测量系统研究

基于板料应变测量的现状和不足,本文基于数码相机构建了板料应变测量系统,并以图像处理和图像测量的原理为基础,基于C＋＋语言开发了以图像预处理和二值图像的标定和测量为主要模块的板料应变测量软件系统。最后通过实例应用,说明了系统的有效性。     

A new approach for evaluating sheet metal forming based on sheet drawing test. Application to TRIP 700 steel

Sheet formability has usually been evaluated by experimental tests that act under different conditions to those the material is subjected to during industrial processing. The different variables acting on the process are not split up sufficiently to be separately analysed. In this work, a new approach to evaluate formability in pure shear deformation has been developed. For this purpose, a new apparatus has been devised to do drawing tests to thin sheets which permits the calculation of deformation work as a function of the drawing strain. Moreover, the coefficient of friction under high pressure values can be modelled. One application to TRIP 700 steel and the friction results have been considered up to an apparent pressure of 1900 MPa. Deformation work has been analysed and inhomogeneity deformation has been evaluated in terms of redundant work as a function of the geometry of the die. The obtained results agree with the theory of plasticity and demonstrate the utility of the methodology presented herein.     

基于人工神经网络的板料激光成形工艺优化

采用BP算法的人工神经网络系统，以激光能量、光斑大小、扫描速度、矩形板料的厚度和宽度作为输入层节点，预测板料激光成形的温度峰值和弯曲角度，并将该系统用于08F薄钢板激光弯曲成形的工艺参数优化之中，可以快速获得最大成形角度所对应的最优工艺参数组合。     

薄板多点成形中的拉裂现象研究

拉裂现象在薄板成形过程中很容易发生。文章采用有限元数值模拟手段,研究了薄板多点成形过程中的拉裂现象,分析了有压边多点成形时鞍形件的拉裂情况,提出了能够避免拉裂的柔性压边成形方式,分析了刚性压边与柔性压边成形时的成形极限与成形效果等,证明了柔性压边成形能够很好地解决板料起皱与拉裂的矛盾关系。当采用刚性压边多点成形时,加大压边力板料可能拉裂,减小压边力板料可能起皱;而采用柔性压边多点成形方式可以有效避免起皱和拉裂的发生,并且大大提高变形量,得到更好的成形结果。     

等离子体弧柔性成形技术研究

等离子体弧柔性成形技术是利用热应力和热应变来实现板材成形的新型技术,在国内外逐渐成为研究的热点.因为等离子体弧与其它热源相比更经济、安全、灵活、实用,但是目前相关工作研究非常有限,如仅利用直线扫描路径研究板材成形情况,考察弯折区域金相组织的变化等问题,在探讨了薄板等离子体弧柔性成形技术的成形机理基础上,通过不同形状的板材,以实验分析的方法探索了直线扫描和曲线扫描的差异以及板材的几何形状对成形结果的影响.     

Bulk forming of sheet metal

Ever increasing demands on functional integration of high strength light weight products leads to the development of a new class of manufacturing processes. The application of bulk forming processes to sheet or plate semi-finished products, sometimes in combination with conventional sheet forming processes creates new products with the requested properties. The paper defines this new class of sheet-bulk metal forming processes, gives an overview of the existing processes belonging to this class, highlights the tooling aspects as well as the resulting product properties and presents a short summary of the relevant work that has been done towards modeling and simulation.     

金属薄板直壁件数字化渐进成形过程的实验研究

金属薄板直壁件的成形是数字化渐进成形技术中的热点和难点之一。本文基于数字化渐进成形的基本原理提出了一种加工金属直壁件的方法,在实验中研究金属薄板直壁件的成形过程,了解直壁成形机理和控制成形过程的工艺措施。