关键词: 非线性有限元分析, 薄板冲压成型, 自适应网格加密, 误差估计, 子循环算法

Abstract: In the finite element simulation analysis of the sheet metal forming process, it is difficult to accurately analyze the stress concentration and strain gradient areas where the field variables change drastically. How to balance the relationship between accuracy and efficiency becomes the key to stamping simulation. Therefore, based on the related theory of nonlinear finite element large deformation and the key technology of mesh adaptation for dynamic simulation, an algorithm for sheet metal forming under the adaptive analysis mode was established. In order to improve the calculation accuracy, an energy error criterion based on the unit strain energy increment and a geometric error criterion based on the geometric characteristics of sheet metal forming were proposed. Combining these two types of error criteria, an error judgment criterion based on an adaptive analysis algorithm was established. In order to enhance the calculation efficiency, by introducing a damper factor, a damper subcycling algorithm was proposed, which divided the adaptive sheet element unit into several regions according to the time step, and each region was integrated separately according to the time step. The results show that the algorithm improves the accuracy and efficiency of finite element simulation of sheet metal forming. 

Key words: nonlinear finite element analysis, sheet metal forming, adaptive mesh refinement, error estimation, subcycling algorithm