Structural damage state analysis method based on elasticity-plasticity-damage decomposition

The invention discloses a universal structural damage state analysis method, and belongs to the field of structural performance evaluation. According to the method, the strain of a nonlinear material is subjected to elastic-plastic-damage decomposition, so that the main calculation amount of elastic-plastic damage finite element analysis is concentrated on the updating and decomposition of small-scale damage and a plastic matrix; damage strain and plastic strain decomposed by the method are intermediate variables when a displacement field is solved by low-rank perturbation of a structure control equation and can be directly obtained in the solving process, and influences of rigidity degradation and plastic strain can be considered at the same time by constructing a material damage state quantitative index based on damage and plastic strain. Quantitative analysis of the damage state of any part of the structure is realized. According to the method, a tedious data extraction process and a time-consuming stiffne