为了在进行结构非线性分析时考虑低碳钢在外部荷载的作用下发生的塑性变形 ,同时由于材料内部缺陷的扩展而导致的材料物理力学性质的劣化 ,将损伤本构关系引入了有限元方程 .基于弹塑性各向同性损伤的假定 ,对损伤有效应力的表达式进行了推演变换 ,在更新的Lagrange格式的虚功方程的基础上 ,推导出了考虑材料损伤和混合强化本构模型的非线性有限元基本方程 ,并给出了求解的方法和具体步骤 ,所得结论适用于分析结构的低周疲劳、曲屈后行为以及结构极限承载力等 .将厚铝环反向应变的计算结果与试验结果进行了比较 ,证明考虑各向同性弹塑性损伤的有限元模型对于上述问题是有效的 In order to consider the plastic deformation of low-carbon steel under the action of external load in the structural nonlinear analysis and the physical and mechanical properties of the material due to the expansion of internal defects, the damage constitutive relation is introduced into the finite element equation Based on the assumptions of elastic - plastic isotropic damage, the expression of effective damage damage is deduced and transformed. Based on the updated Lagrange ’s virtual work equation, the non - The basic equations of linear finite element method are given, and the methods and specific steps are given. The conclusions are suitable for analyzing low-cycle fatigue, post-buckling behavior and ultimate bearing capacity of structures, etc. The calculation results of the back- The experimental results are compared to prove that the finite element model considering isotropic elastic-plastic damage is effective for the above problems