Fatigue life prediction method of face‐centered cubic single‐crystal metals under multiaxial nonproportional loading based on structural mechanical model

Abstract 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 elastoplastic constitutive equations and damage constitutive equations of the face‐centered cubic (FCC) structure subjected to multiaxial cyclic loading were derived, and the damage evolution law of the body–bar–plate mechanical model was investigated. Then, the meso‐damage evolution equation was established under multiaxial nonproportional loading. Subsequently, the relationship between the fatigue performance and microstructure under multiaxial nonproportional loading was investigated, and a damage mechanics–finite element method (FEM) with consideration to the damage evolution is proposed. The proposed model and method provide a new approach for predicting the fatigue life of metal materials.