循环应变下多晶铜非Massing现象的模拟

Simulation of Non-massing Behavior of Polycrystalline Copper under Cyclic Strain Condition

对多轴应力状态下的循环本构模型进行修正,在引入加载历史参数演化方程来刻画材料非比例特性的塑性模型基础上,通过在背应力演化方程中加入额外非线性项,以实现对金属材料非Massing现象的描述;利用隐式积分方法推导出新的应力和背应力积分方程以及整体迭代所需的一致切线刚度矩阵,借助有限元软件ABAQUS的用户子程序UMAT,将模型嵌入有限元分析软件中,对具有典型非Massing现象的多晶铜材料进行数值模拟,并将所得模拟结果与实验结果加以比较.结果表明,两者较吻合.

A cyclic plastic model in which an additional term is conducted into the evolution of back-stress in order to predict non-massing behavior of material was employed. Based on radial-return method and back Euler integration, new stress and back-stress contributions were obtained, tangent stiffness matrix for global iteration was deduced as well. The model was implemented into the commercial finite element software ABAQUS by user-subroutine UMAT. Examples were approached for polycrystalline copper which is typical non-massing material. The results show that the finite element simulation agrees well with the experimental data.