U形件磁脉冲辅助弯曲回弹控制及变形分析

摘要

To evaluate the efficacy of springback-control effect during electromagnetically assisted sheet metal stamping (EMAS), the experimental schemes of electromagnetically assisted bending of U-shaped parts were established on the basis of the idea of EMAS, and the involved springback-control effect and deformation characteristics undergoing pulsed magnetic forces were investigated. The results show that the way of applying pulsed magnetic forces to the bending area can effectively reduce springback, and which will be enhanced with the increasing of discharge energy and discharge times. During EMAS, the springback control effect of magnetic force is mainly presented in two aspects: the role of magnetic force changing the strain distributions of bending area and the role of tool-sheet interaction during high-speed loading. Both processes can successfully reduce spingback. Moreover, the way of many times of small discharges can not only control springback, but can also improve the deformation quality of the bending area, which provides a meaningful reference for engineering application.%为评价磁脉冲辅助冲压(EMAS)成形在回弹控制方面的作用，基于磁脉冲辅助冲压工艺原理，建立 U 形弯曲过程的磁脉冲辅助弯曲回弹控制工艺模拟试验方案，系统研究该过程中脉冲电磁力对回弹控制的效果和对变形的影响。结果表明：将脉冲电磁力作用于弯曲件角部可有效实现对弯曲回弹的控制，且随着放电能量和放电次数的增加，回弹控制效果增强。磁脉冲辅助冲压成形中，脉冲电磁力对回弹控制的作用主要表现在两个方面：脉冲磁场力控制弯曲角部位的应力应变分布作用和板坯与模具的高速冲击效应，两个过程均能有效减小弯曲回弹。利用脉冲电磁力时，采用小能量多次放电不仅可以控制回弹，而且可以有效地改善弯曲件角部的变形分布，为其工程应用提供借鉴。