A procedure for estimating the total fatigue life of notched and cracked members

A model for combining strain cycle fatigue and fracture mechanics concepts in order to estimate the total fatigue life of notched and cracked members is presented. The model provides a nonarbitrary definition of fatigue crack initiation length. This crack length serves as a bridge between crack initiation and crack propagation analysis procedures. Material properties, loading, and geometric parameters are incorporated into the model in such a manner that the relative portion of fatigue life spent in initiation and propagation varies appropriately. Estimates of total fatigue life are compared with experimental data reported in the literature for two steels and an aluminum alloy.