【作者】 张全发；

【导师】 李明哲；

【作者基本信息】 吉林大学 ， 材料加工工程， 2006， 硕士

【摘要】 多点成形是基于产品的数字化几何信息,由产品的三维CAD模型直接驱动可调基本体群,通过工具的包络面实现金属板材曲面成形的一种柔性加工方法。在冲压成形中,压边技术是抑制起皱等缺陷的关键技术,对提高冲压件的成形质量有着重要意义。带压边的多点成形压力机的压边机构是由共用一套压力供给系统的四十个独立运动压边缸组成,配合刚性压边圈和柔性压边圈,可以实现均匀压边力刚性压边多点成形和均匀压边力柔性压边多点成形。当为多点成形压力机的压边装置增加几套压力供给系统时,便可以实现非均匀的压边力多点成形。本文采用有限元数值模拟方法,使用动态显式有限元分析软件,对变形程度较复杂的大曲率三维曲面件的几种压边工艺进行数值模拟。分析了刚性压边、柔性压边及非均匀压边力多点成形的成形质量和成形规律,通过对比分析表明,柔性压边成形可以克服刚性压边成形在成形大曲率三维曲面件时同时出现的起皱和拉裂缺陷,明显提高成形质量;非均匀压边成形相对于均匀压边成形可以在一定程度上提高曲面件的成形质量,这为开发新型高成形性能的多点成形压力机提供了理论依据。更多还原

【Abstract】 Multi-point forming (MPF) is a flexible manufacturing technology for metal-sheet forming. It is based on numerical geometry information of product and the die is divided into a matrix of discrete elements which are directly driven by 3-D Model of product. The flexible forming process of metal-sheet is implemented by the contour surface of elements group. It can carry out dieless forming, optimizing forming way, no spring back forming and little machine forming large parts. MPF has found its extensive application fields such as the manufacturing of the fuselage of aircraft, the hull of ship, titanium alloy skull, city sculpture etc.For metal-sheet forming, a blank-holder has important function in preventing crackle, crinkle and improving the forming quality of metal-sheet. The blank-holder set of MPF is composed of forty blank-holder elements, and all of them are driven by its unique hydraulic equipment. When an appropriate thickness blank-holder is selected in MPF, the rigid blank-holder or the flexible blank-holder multi-point forming can be realized. The uneven blank-holder force metal-sheet forming is a foreland of international and in-country research. If supplying the blank-holder elements with several hydraulic equipments, it can realize uneven blank-holder force forming. When forming little curvature 3-D surface, the rigid blank-holder way can reach the quality of metal-sheet forming. Therefore this paper chooses large curvature 3-D surface formings as examples which have more complicated and more difficult forming process. With the finite element analysis (FEA) method, the MPF process with the flexible blank-holder, the MPF process with the rigid blank-holder and the MPF with uneven blank-holder force all have been simulated. This paper has studied their defects like crackle and crinkle,and更多还原