A Study on Plastic Shrinkage Coefficient of Crack Opening/Closing Model at a Crack Extension

In the previous paper, we developed a simulation model of fatigue crack opening and closing phenomena for predicting RPG load under an arbitrary stress distribution field. By using the simulation model, effects of stress ratio and residual stress distribution on fatigue crack propagation rate are quantitatively assessed. However, it became clear that the estimated fatigue life is longer than experimental one under decreased maximum load while keeping minimum load and a overload condition.In this paper, we considered the plastic shrinkage at an immediate generation of new crack surface for the purpose of solving the above problem and modified the above simulation model. And then, we carried out fatigue crack propagation analyses under various conditions and compared the estimated RPG loads and crack growth curves with the experimantal ones. As a result, it is confirmed that modified simulation model is appreciable to various amplitude fatigue loading tests.