多晶金属材料的三维组集式弹塑性本构模型

本文从分析多晶金属材料的细观组织在弹塑性变形中的贮能和耗能机制入手,提出一个三维组集式弹塑性本构模型。该模型将材料单元抽象成沿三维空间各方向均匀分布组件的集合体,方向组件反映材料的细观性态并在宏观上协调变形,所有方向组件的内力总效应构成宏观应力。文中导出了显式的弹塑性本构关系,并与Budiansky的复杂加载试验结果及其它塑性模型进行了对比。

A 3-D COMPOSITE CONSTITUTIVE MODEL OF ELASTO-PLASTICiTY FOR POLYCRYSTALLINE MATERIALS

This paper is aimed at developing an elasto-plastic constitutive model for polyc-rystalline materials. The model is an energy-equivalent system composed of extensivecompressive components well-oriented and distributed uniformly in the 3-D space to simulate how the mic-rostructures of materials store and dissipate energy during deformation and slippage. The components are extended/compressed compatibly with the overall strain and each of them undergoes its own elongation history dependent on its orientation. The overall stress defined as the work conjugate tensor with respect to the incremental strain tensor is just balanced by the resultant of loads exerted on the components so that the load-elongation relation of the components can be determined from conventional material experiments.By taking such a system as a material element, an explicit constitutive equation has been derived and used to predict stress-strain responses of materials under complex loading processes Comparison is made with experiments and previous plasticity theories.