Modeling of fatigue crack growth under constant and variable amplitude loading

In this paper, a modeling of fatigue crack growth of thin walled tube aluminum alloy with circumferential crack under constant and variable amplitude loading are presented. Three Fatigue crack growth models, namely Walker, Forman and NASGRO were examined. The results showed that the simulation of the fatigue crack growth under constant and variable amplitude loading in the proposed technique is an efficient tool and also the different models gave different fatigue crack growth behavior. There are many factors affecting the fatigue crack growth in structures. Crack initiation and stress ratio are studied and shown a great influence on the life of the thin walled tube. The NASGRO model was found to be the most appropriate model for the variable amplitude loading. Therefore, this model may be suggested for use in critical applications in studying fatigue crack growth for different structures under variable amplitude loading