刚塑性有限元模拟中体积变化问题处理方法

分析了在塑性有限元分析金属体积成形问题中引起体积变化的原因 ,指出在采用罚函数方法引入体积不可压缩条件的刚塑性有限元模拟中惩罚因子、增量步长、节点调整、网格密度和重划次数等是引起体积变化的主要原因。针对所分析原因 ,在现有的方法基础上提出基于三维有限元的节点调整和体积补偿新方法 ,并在实际模拟中应用 ,得到较好的效果 ,提高了模拟的精度和可信度。

Computational strategies for element volume change control in the simulation of metal forming using rigid-plastic FEM

In this paper, several reasons for element volume change in FEM analysis of metal forming are discussed. In the method of rigid-plastic FEM with a penalty function, penalty coefficient, time increment, density of mesh, times of re-meshing and adjustment of the touch-mould nodes cause the element volume change effectively. On the basis of analyzing all these reasons, the method to determine the value of penalty coefficient and a new strategy to adjust the touch-mould nodes in three-dimensional FEM for element volume control are presented. An actual calculation is conducted to verify these measures. The accuracy and trustiness of FEM simulation are improved by good results.