Analytical model of fatigue crack growth retardation due to overloading

A model is suggested to describe the influence of overloading on the fatigue crack propagation process. The model includes three factors that can affect significantly the crack growth rate : the increasing of the material resistance to crack growth due to the crack tip blunting ; the’ residual stress field in the process zone affecting the threshold of microdamage accumulation ; the change of microstructural properties close to the new-blunted crack tip that changes the initial conditions of the microdamage accumulation process. It is shown that the joint account of two or three listed factors adequately explains the crack growth retardation due to overloading