共查询到19条相似文献,搜索用时 218 毫秒
1.
数字化渐进成形技术是一种新兴的金属板料柔性成形技术。通过有限元数值对其成形过程模拟,能够对渐进成形的研究起理论指导作用。利用有限元分析软件LS-DYNA对金属板料渐进成形的过程进行了模拟。根据试验特点建立了相关的有限元模型,对其中工具头的运动轨迹和加载方式进行了简化,同时根据实际成形特点建立了边界条件和约束,保证了模拟的真实性,并据此模型分析了成形过程中板料上的应力、应变分布特点。 相似文献
2.
金属板料渐进成形有限元仿真过程中复杂成形路径的构建方法 总被引:3,自引:0,他引:3
提出一种用于获得复杂空间运动轨迹的方法——虚拟靠模导向法。该方法借鉴了数控加工中COPY铣的思想,利用轨迹生成球在由零件派生出的虚拟靠模表面上的持续运动来模拟实际成形工具的运动过程,从而获得最终成形路径。基于该思想和简单的运动学原理,轨迹球与虚拟靠模有限元模型被构建起来。通过对计算过程进行分析,确定运用该法时适合的加载力、成形速度及计算精度的影响因素。因该法完全基于有限元模拟计算,故获得的成形路径可直接导入至后续的金属板料成形过程的模拟分析。该法已在有限元软件PAMSTAMP平台上得以实现,并主要用于金属板料渐进成形过程的有限元仿真。 相似文献
3.
基于MARC的板料冲压成形过程有限元模拟研究 总被引:1,自引:0,他引:1
甘辉 《机械制造与自动化》2009,38(1)
通过合理制定零件的成形工艺、模具参数来消除零件缺陷、提高成形品质是金属板料冲压成形的重要任务.通过探讨成形过程的数值模拟来分析金属板料各部分在冲压成形过程中的变形情况,预测成形缺陷,分析影响零件成形品质的因素的方法.以圆筒形拉深件的冲压成形为例,介绍应用商用有限元软件MARC对成形过程进行有限元模拟分析的实现技术,其分析结果与实验相符. 相似文献
4.
5.
6.
7.
8.
板料成形时极限拉深系数的确定 总被引:2,自引:1,他引:1
以金属板料拉深成形时凸模圆角处和凸缘区金属的变形为基础,提出了一个确定板料成形时极限拉深系数的判据。该判据可用于定量研究材质和成形工艺参数对极限拉深系数m k值的影响。并且,在金属板料拉深成形时凸模圆角处金属的变形分析的基础上,应用本文判据导出了平底杯型件拉深时极限拉深系数的计算式。同时,从计算结果的分析中,进一步阐明了板料拉深时合理工艺参数的选择依据。试验结果表明:该判据确定的极限拉深系数m k值准确,且其适用性强。 相似文献
9.
圆锥形渐进成形制件成形精度研究 总被引:5,自引:0,他引:5
成形精度差是金属板料渐进成形工艺的重要缺陷。针对渐进成形精度评价问题,提出位移误差评价法,即通过确定测量方向上的变形位移来衡量其成形精度。利用误差位移法对一组圆锥形成形制件进行研究,提出渐进成形过程中金属板料回弹和成形工具系统刚度是影响成形制件精度的主要因素。且成形过程中制件成形角一定,回弹一定,成形角变化,回弹变化,回弹量与成形角呈非线性关系。在此基础上,提出提高制件成形精度的解决方案:增加成形工具系统刚度。试验证明补偿回弹和成形工具系统刚度不足引起的尺寸偏差,或者增加成形工具系统刚度,都可显著提高渐进成形制件精度。 相似文献
10.
金属直壁筒形件数控渐进成形工艺研究 总被引:6,自引:0,他引:6
介绍了金属板料数控渐进成形工艺的成形原理、变形分析、直壁筒形件成形的工具路径设计、实验条件及结果分析。根据正弦定律 ,金属板料数控渐进成形工艺 ,不能一次成形出直壁筒形件 ,要成形直壁筒形件 ,必须进行多次成形。为了尽快逼近直壁筒形件 ,设计了平行直线型等三种工具路径方案 ,通过实验和结果分析 ,找到最佳方案。 相似文献
11.
12.
13.
Numerical investigation of multi-point forming process for sheet metal: wrinkling, dimpling and springback 总被引:2,自引:2,他引:0
Zhong-Yi Cai Shao-Hui Wang Ming-Zhe Li 《The International Journal of Advanced Manufacturing Technology》2008,37(9-10):927-936
Multi-point forming (MPF) is a new flexible technique for manufacturing three-dimensional sheet metal parts. In this procedure, a pair of opposed matrices of punch elements substitute for the conventional fixed shape die sets, and the sheet metal can be formed rapidly between the matrices. Extensive numerical simulations of the processes for forming spherical and saddle-shaped parts were carried out by dynamic explicit finite element analysis. The contacting process between sheet metal and punch elements in MPF was investigated, and the variations of forming force with respect to the tool travel were analyzed. The wrinkling processes were simulated, and the MPF limit curves without wrinkles for spherical and saddle-shaped parts were obtained. Dimple is a particular defect in MPF, through the comparison of the thickness strains calculated by solid FE and shell FE, the finite elements appropriate for the numerical analysis of dimpling were detected, and the limit forming force without dimples was determined. Springback processes of MPF were simulated based on explicit-implicit algorithm. The springbacks and their distributions under different conditions were investigated. 相似文献
14.
J. W. Yoon I. S. Song D. Y. Yang K. Chung F. Barlat 《International Journal of Mechanical Sciences》1995,37(7)
A variational formulation and the associated finite element (FE) equations have been derived for general three-dimensional deformation of a planar anisotropic rigid-plastic sheet metal which obeys the strain-rate potential proposed by [11.]. By using the natural convected coordinate system, the effect of geometric change and the rotation of planar anisotropic axes were efficiently considered. In order to check the validity of the present formulation, a cylindrical cup deep drawing test was modeled for a 2008-T4 aluminum alloy sheet sample. Eating simulations were performed and planar anisotropic material properties were experimentally determined. Even though quantitative agreement was not fully achieved, reasonably good agreement was found between the FE simulation and the experiment in thickness strain distribution and caring. No numerical difficulty due to planar anisotropy was encountered, and the computational procedure was found to be very stable, requiring only moderate computational time. The results have shown that the present formulation for planar anisotropic deformation can provide a good basis for the analysis of sheet metal forming processes for planar anisotropic materials, especially for aluminum alloy sheets. 相似文献
15.
16.
介绍了将自动测量技术、离散点直接生成有限元网格技术 ,板料有限元数值模拟仿真技术等集成在一起 ,建立金属板料快速仿真集成系统 ,使用 IDEF0法建立了集成系统的功能模型 ,并说明了各模块的具体作用 ,为整个系统的建立奠定了基础。 相似文献
17.
固体颗粒介质板材成形工艺是采用固体颗粒微珠代替刚性凸(凹)模(或弹性体、液体)的作用对板材拉深成形的新工艺。选用非金属固体颗粒介质——GM颗粒作为研究对象,以固体颗粒介质在高应力水平下的体积压缩试验和摩擦强度试验为基础,应用散体力学理论中扩展的Drucker-Prager线性模型构建固体颗粒介质有限元材料模型。以具有非轴对称性的方盒形件为代表,进行固体颗粒介质成形工艺的有限元模拟,研究成形过程中板材的流动特征和壁厚分布规律。工艺试验成功得到方盒形零件,将加载曲线、成形过程变形特征和壁厚分布曲线与数值模拟结果比对较为吻合。分析表明,采用以散体力学为基础建立的固体颗粒介质材料模型进行工艺模拟,能够得到与试验较为接近的变形特征和力能参数,可以应用于制定工艺方案的依据,为该技术在板材成形中的应用起到指导和借鉴作用。 相似文献
18.
基于塑性流动本构关系的多步反向模拟法 总被引:1,自引:0,他引:1
传统板料成形反向模拟法的本构关系是建立在塑性形变理论的基础上,无法考虑变形历史的影响.提出一种新型有效的多步反向模拟法,采用弹塑性材料模型提高计算精度:引入DKT12薄壳单元考虑类似模具圆角处的弯曲一反弯曲效应等应变历史的影响.提出一种基于塑性流动理论的本构方程,可以快速准确地处理弹/塑性变形及加载/卸载状况,提高了应... 相似文献
19.
Maziar Ramezani Zaidi Mohd Ripin 《The International Journal of Advanced Manufacturing Technology》2012,59(5-8):491-505
This paper deals with the deep drawing of metal cups using the Marform process. Using this technique, higher limiting drawing ratios can be obtained compared with the conventional deep drawing process. The analytical model of the process is presented initially, followed by the finite element simulations using ABAQUS software. A new friction model based on local contact conditions is presented and used in the finite element (FE) simulations of the process. Compared with traditional Coulomb friction model, the results of the FE simulations with the new friction model showed good correlation with experimental results. The results showed that the maximum thinning occurs at the punch profile portion, and by increasing the forming pressure, thinning of the sheet metal propagates from the punch profile portion to the side wall. At low forming pressures, wrinkles appear in the flange, whilst at higher pressures, fracture is the main defect of the Marform process. 相似文献