THE USE OF APPROXIMATE STRAIN LIFE FATIGUE-CRACK INITIATION PREDICTIONS

This paper describes the most commonly used approximate strain-life equations for prediction of fatigue crack initiation. Despite the development of advanced multiphase material memory models, the simple strain-life equations are useful 'first-shot' approximations of a component's resistance to fatigue crack initiation. There are, however, certain precautions that should be observed when using these equations. Selection of appropriate cyclic material properties is of utmost importance. These properties must be internally consistent; however, many values given in published literature are not. A sensitivity analysis is also presented for predicted fatigue life with respect to percentage error in cyclic material properties.