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复合塑性成形新技术及其应用 总被引:12,自引:2,他引:12
介绍了几种复合塑性成形新技术,包括热锻冷锻复合技术、板料冲压冷锻复合技术、以及结合铸造和锻造特点开发出来的铸造锻造技术和半固态成形技术,以及它们在工业生产中的应用情况。 相似文献
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本文基于弹粘塑性理论,推导出考虑空洞效应的超塑性流动本构方程,对板料超塑性拉伸进行了模拟研究,获得的应力应变曲线具备超塑性材料的流动特征,这表明新本构模型能够较好地描述超塑性流动特性;同时基于新本构模型对板料自由胀形过程进行了数值模拟,研究了各变形阶段的厚度分布,并与Backofen模型的计算结果进行了比较。 相似文献
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金属塑性成形时板料与模具真实接触面积研究 总被引:3,自引:0,他引:3
从微观的角度出发,分析了金属塑性为形过程中,模具与板料表面在外力作用下,影响真实接触面积大小的因素。指出在一般的变形过程中,真实接触面积只占投影面积很小一部分。 相似文献
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板料成形数值模拟软件的研究 总被引:2,自引:0,他引:2
研究了板料成形数值模拟软件的发展概况,比较了通用数值模拟软件和板料成表专用数值模拟软件的异同点,并结合作者开发和使用数值模拟软件的经验和体会,指出了开发和选用板料成表数值模拟软件的方法和原则,最后,阐述了板料成形数值模拟软件的发展方向。 相似文献
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板料成形中的有限元数值模拟技术 总被引:14,自引:0,他引:14
综述了板料成形中有限元数值模拟技术的发展及我国目前板料成形数值模拟技术的研究和应用水平,论述了美、日等发达国家在汽车覆盖件模拟方法取得的进展,指出了今后的研究方向。 相似文献
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限制自由度单元及其在板料成形过程数值模拟中的应用 总被引:2,自引:0,他引:2
根据板料成形过程的特点,提出一种用于板料成形分析的新单元模型-三维限制自由度单元模型,这种单元既没有膜单元不能考虑横向剪应力的遗憾,也不受壳单元对于局部大的限制毛坯后机加工同时克服了体单元解决板结构问题时刚度矩阵奇异的缺点。 相似文献
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Drawbeads in sheet metal forming 总被引:4,自引:0,他引:4
M. Y. Demeri 《Journal of Materials Engineering and Performance》1993,2(6):863-866
Drawbeads are used to control the flow of sheet metal into the die cavity during stretch-draw forming of large panels. They
prevent wrinkling in formed panels, reduce the blankholder force, and minimize the blank size needed to make a part. Drawbead
restraining forces (pulling forces) and failure locations in the formed sheets are usually evaluated by using drawbead simulation
tooling. In this article, a drawbead simulation apparatus is used to assess the influence of variation in material, bead penetration,
and fric-tion conditions on the drawbead restraining force. Results from the test can be used as input for sheet metal forming
simulation programs. 相似文献
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Comparison of different analysis models to measure plastic strains on sheet metal forming parts by digital image processing 总被引:2,自引:0,他引:2
The principal strains of sheet metals and their limitations while forming can be obtained by using a strain measurement system. A strain measurement may employ one of two different approaches: namely the total least square optimization method or the multiple regression analysis (MRA) method. With both methods plastic strains of deformed parts are calculated based on the non-deformed reference configuration designated by a circle and the deformed configuration, which is a curve-fitting ellipse. In the MRA method, the mathematical formula is simpler reducing the required computations than that of the total least square optimization method. While the formula has a greater margin of error, this margin proves less than significant in the practical application of the method’s results.Information from the results of a strain measurement system can be used to determine the sheet metal’s formability and strain path allowing engineers to determine at which point, the sheet metal will crack. They can then change the thickness and the material of the sheet metal, or modify its shape accordingly to maximize the metal’s efficiency. Strain measurement systems possess practical advantages in their actual application; they improve the quality of sheet metal being produced by minimizing defects in sheet metal during production. One industrial case study of fine stamping electronic part is discussed to demonstrate the proposed methodology. 相似文献
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起皱是传统冲压成形和多点成形时共有的现象,尤其在无压边成形方式下很容易发生。文章采用有限元数值模拟手段,针对两种多点成形工艺和整体模具成形过程中产生的起皱现象进行了探讨,分析了无压边成形过程中不同的成形工艺对球形件起皱的影响。文章用显式动力学算法进行了数值模拟,结果表明,采用多点模具成形工艺成形1mm厚度的板料时,曲率半径为200mm的成形件起皱明显;但在相同条件下,用多点压机成形工艺的成形件结果良好,甚至成形厚度为0.5mm,曲率半径为150mm的球形件也没有起皱;而在这两种条件下,整体模具成形都有微小的起皱发生。也就是说,多点压机成形方式比多点模具成形方式以及整体模具成形方式效果更好,缺陷少,能够得到更大的变形量。 相似文献
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