共查询到18条相似文献,搜索用时 156 毫秒
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利用有限元MSC.MARC软件,通过建立试验钢板的拉延筋模型,对其拉延过程进行了模拟,得到了板料被拉延筋夹持后移动过程的应力和板料厚度的分布。并且通过提取板料的节点,得出其节点力,把所有节点力相加即得到拉延阻力。 相似文献
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在模拟软件Dynaform中,将文献[3]中建立的拉延筋阻力计算模型作为等效拉延筋使用,模拟分析了表盘座某部件的成形.分析结果表明,在分析起皱、破裂等成形问题时,文中建立的拉延筋阻力计算模型比使用Dynaform自带等效拉延筋更接近使用真实拉延筋模拟的结果. 相似文献
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等效拉延筋模型及其在板料成形数值模拟中的应用 总被引:8,自引:0,他引:8
讨论等效拉延筋的建模方法、常用模型及其在板料成形数值模拟中的应用情况,并指出研究中仍存在的问题及今后的发展方向。 相似文献
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采用板料成形有限元分析软件Dynaform5.7对某空调器钣金件的冲压成形过程进行了数值模拟,预测工艺参数如压边力、拉延筋对成形质量的影响。结果表明调整压边力可控制材料的总体流动,有效改善起皱和成形不足等成形缺陷。设置拉延筋直接影响材料的局部流动,增加压料面上相应部位的进料阻力,但如何设置拉延筋的位置、根数和形状是取决能否得到满意的成形质量的关键。通过数值模拟技术调整压边力大小和拉延筋以得到合理的设计方案,改进后方案的成形质量好,无起皱和破裂等缺陷,变形均匀,产品精度符合要求。 相似文献
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真实拉延筋参数化建模及其在薄板冲压仿真中的应用 总被引:2,自引:0,他引:2
提出一种参数化的拉延筋网格模型建模方法,在自主开发的有限元前处理软件中,建立了具有真实几何尺寸的半圆形、三角形拉延筋和拉深槛的网格模型,并提供了灵活的拉延筋布置手段。提出一种改进的全四边形网格加密方法,对成形过程中将会流过拉延筋区域的板料网格,以及可能与模具上曲率变化大的区域相接触的板料网格进行加密操作,以满足网格的适应性要求。提出一系列的网格拓扑清理模版,对加密后的网格进行拓扑清理操作,有效地提高了板料网格的质量。大量的算例证明所提出方法具有较高的精度和较强的工程实用性。 相似文献
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在汽车零件的成形过程中,拉延筋的方式和布置方案对零件的拉深成形质量有重要影响。本文以有限元模拟软件AutoForm为平台,以某型号汽车结构件为例,分别研究了拉深成形过程中等效拉延筋、真实拉延筋两种布置方式对零件成形质量的影响,通过对比分析模拟结果,最终确定了两种方式下满足零件成形质量的拉延筋布置方案。 相似文献
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The problem analyzed here is a sheet metal forming process which requires a drawbead. The drawbead provides the sheet metal enough tension to be deformed plastically along the punch face and consequently, ensures a proper shape of final products by fixing the sheet to the die. Therefore, the optimum design of drawbead is indispensable in obtaining the desired formability. A static-explicit Finite element analysis is carried out to provide a perspective tool for designing the drawbead. The finite element formulation is constructed from static equilibrium equation and takes into account the boundary condition that involves a proper contact condition. The deformation behavior of sheet material is formulated by the elastic-plastic constitutive equation. The finite element formulation has been solved based on an existing method that is called the static-explicit method. The main features of the static-explicit method are first that there is no convergence problem. Second, the problem of contact and friction is easily solved by application of very small time interval. During the analysis of drawbead processes, the strain distribution and the drawing force on drawbead can be analyzed. And the effects of bead shape and number of beads on sheet forming processes were investigated. The results of the static explicit analysis of drawbead processes show no convergence problem and comparatively accurate results even though severe high geometric and contact-friction nonlinearity. Moreover, the computational results of a static-explicit finite element analysis can supply very valuable information for designing the drawbead process in which the defects of final sheet product can be removed. 相似文献
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板材冲压成形的晶体塑性有限元模拟 总被引:3,自引:1,他引:2
将率相关晶体塑性本构理论引入Mindlin曲壳单元模型与动力显式有限元法,采用切线系数法计算剪切应变率,根据晶体取向正态分布规律在单元积分点处分配晶体取向,按各晶体取向体积分数的加权平均计算多晶体应力,开发晶体塑性动力显式有限元程序,实现板材冲压成形过程模拟和晶体取向演化预示.以主要初始织构为铜织构和S织构的轧制铝板为对象,对方盒件冲压成形过程及织构演化进行数值模拟,计算结果与试验结果呈现出较好的一致性.通过晶体弹塑性有限元法不仅可以预示板材宏观成形构形变化,而且能够预测板材织构的演化情况.模拟结果显示在方盒件冲压成形过程中,铜织构和S织构为不稳定取向,变形后逐渐转到其他取向. 相似文献
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In this paper, we describe the numerical modelling of drawbead forces required to draw a sheet metal through a bead with a constant cross section. The model is formulated using an elasto-plastic large strains finite element method combined with an improved numerical technique taking into account the contact and friction conditions, based on linear programming techniques and fixed point conditions. The numerical simulations were carried out with various drawbead geometries and the results are expressed in terms of drawing restraining force versus drawing movement, as a function of the drawbead geometry, gap conditions and friction conditions. With this procedure it is also possible to determine the main deformation paths in the drawbead region where the bending strain predominates over the membrane strain. The results obtained are compared with experimental data and the agreement proves to be good. The calculated results can be used as a basis to obtain better approximations of the drawbead constitutive equations to be used in general 3D FE simulation codes in cases where it is impossible to exactly determine the drawbead geometry. 相似文献
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MA Linwei MO Jianhua 《机械工程学报(英文版)》2008,21(1):31-35
Single-point incremental forming (SPIF) is an innovational sheet metal forming method without dedicated dies, which belongs to rapid prototyping technology. In generalizing the SPIF of sheet metal, the deformation analysis on forming process becomes an important and useful method for the planning of shell products, the choice of material, the design of the forming process and the planning of the forming tool. Using solid brick elements, the finite element method(FEM) model of truncated pyramid was established. Based on the theory of anisotropy and assumed strain formulation, the SPIF processes with different parameters were simulated. The resulted comparison between the simulations and the experiments shows that the FEM model is feasible and effective. Then, according to the simulated forming process, the deformation pattern of SPIF can be summarized as the combination of plane-stretching deformation and bending deformation. And the study about the process parameters' impact on deformation shows that the process parameter of interlayer spacing is a dominant factor on the deformation. Decreasing interlayer spacing, the strain of one step decreases and the formability of blank will be improved. With bigger interlayer spacing, the plastic deformation zone increases and the forming force will be bigger. 相似文献