弹塑性大变形分析的一种热力学相容的本构模型

以热力学相容的简单机械模型为基础,得到了可以描述材料弹塑性大变形的本构方程,进而导出了可以适用于一般三维问题的增量公式。利用简单加载条件下的积分形式发展了确定材料常数的方法。对圆杆受拉颈缩的大变形弹塑性过程进行了数值模拟,得到了与实验相符的结果。本文发展的模型不采用屈服面的概念,有效地改善了收敛性,提高了计算效率。

A Thermomechanically Consistent Constitutive Model for Finite Elastoplastic Deformation

Based on a thermomechanically consistent mechanical model consisting of springs and plastic dashpots, a plastic constitutive equation for large deformation is derived. Then the incremental form of elastoplastic constitutive equation is developed, which can easily be applied to the finite element analysis and other numerical approaches. The method for the determination of the involved material constants is suggested, which is based on the concept of nonstress configuration proposed by Lee. The necking process of a circular bar subjected to large elastoplastic deformation is simulated and the comparison between the analytical and experimental results is quite satisfactory. The developed model does not use the eoncept of a yield surface, which effectively improves the convergence and computation efficiency.