A unified method of design for fatigue crack growth resistance in structural materials

It is well established that there are two fatigue crack tip driving forces – the cyclic, ΔK, and the static, Kmax. In this study, the effects of each crack tip driving force on crack growth were evaluated for various structural materials. A unified method of design that allows for predicting the response of long and physically small fatigue cracks at positive stress ratios is introduced. Good agreement between predicted and experimental long and physically small fatigue crack growth data was obtained. The importance of this method in material and component design is discussed as part of a contemporary design philosophy.

► A novel design method was developed based on the two parameter approach.
► The relative roles of Kmax and ΔK were identified for a wide range of materials.
► The method accounts for the effects of closure, R, Kmax, and residual stress.
► Long and physically small fatigue crack growth data can be successfully predicted.