Prediction of fatigue crack growth and residual stress relaxations in shot-peened material

The fatigue crack growth, incorporating effects of shot peening, is investigated using two-dimensional finite element analysis. The cohesive zone model, which takes into account the damage evolution under cyclic load, is adopted in the finite element analysis to simulate the potential fracture surfaces. The effects of shot peening on the fatigue crack growth and the relaxation of residual stress under cyclic load are studied. It is shown that the residual stress retards the fatigue crack propagation and the retardation effect depends not only on the shot peening intensity but also on the cyclic load amplitude. The residual stress relaxes nonlinearly as the load cycles increase.