MODELING PLASTICITY-INDUCED FATIGUE CRACK CLOSURE

A numerical analysis of plasticity-induced fatigue crack closure based upon the finite difference method is presented. This new method permits modelling easily fatigue crack growth as well as contacts between fracture faces, without requiring sophisticated algorithms. The model is applied to a wide analysis on the influence of mechanical properties of the material (yield stress, strain hardening capacity) and testing conditions (plane stress or strain, stress ratio, maximum load) on plasticity-induced fatigue crack closure. The agreement with other numerical or experimental results when possible is excellent. It is concluded that plasticity-induced crack closure is determined by compressive residual stresses induced behind the crack tip. These residual stresses depend on plastic strains produced in the material as well as on its strain hardening capacity. © 1990.