Prediction of fatigue life with interspersed mode-I and mixed-mode (I and II) overloads by an exponential model: Extensions and improvements

The current work is an extension of the authors’ earlier work and presents a life prediction methodology under interspersed mode-I and mixed-mode (I and II) overloads. The important controlling parameter in the model is ‘specific growth rate’ (m). It depends on two crack driving forces i.e. stress intensity factor range and maximum stress intensity factor as well as material parameters i.e. fracture toughness, Young’s modulus, and yield stress. The dependence of ‘m’ on these parameters is correlated through a dimensionless parameter ‘l’. It is observed that the present model predicts the end life of post-overload period well in case of 7020 T7 and 2024 T3 Al-alloys.