Structural mechanics model for anisotropic damage and fatigue life prediction method of face-centered cubic metal materials

Based on the characteristics of the sliding surface, sliding direction, and fatigue damage mechanism of metal materials, the mechanical model of a body-bar-plate structure is proposed with consideration to the plastic damage mechanism. The damage evolution law of the body-bar-plate mechanical model was investigated, and the elastoplastic constitutive equations and damage constitutive equations of the face-centered cubic (FCC) structure subjected to multi-axial cyclic loading were derived. Then, the meso-damage evolution equation and failure criterion were established. Subsequently, the relationship between the fatigue performance and microstructure under multi-axial proportional loading was investigated, and a damage mechanics-finite element method (FEM) method with consideration to the damage evolution is proposed. The simulation results are consistent with the experimental data. Therefore, the proposed model and method can accurately predict the fatigue life of FCC metal material under proportional loading and lay the foundation for the further analysis of non-proportional loading fatigue damage.