Evaluation of overload-induced fatigue crack growth retardation parameters using an exponential model

In this study, fatigue crack growth rate in mixed-mode overload (modes I and II) induced retardation zone has been predicted by using an “Exponential model”. The important parameter of this model is the specific growth rate. This has been correlated with various crack driving parameters such as stress intensity factor range, maximum stress intensity factor, equivalent stress intensity factor, and mode mixity, as well as material properties such as modulus of elasticity and yield stress. An equation has been formulated for specific growth rate which has been used to calculate crack growth rate under mixed-mode loading conditions. It has been observed that the crack growth rate predicted by the model is in good agreement with experimental results.