Simulation and Experimental Analysis of Fatigue Crack Growth under Cyclic Loading

The problem of crack growth is a major issue in the prediction and maintenance of engineering structural elements. Prediction of expected life of a structural element due to constant (static) and alternating loading (fatigue) is of major concern to the designers. Prediction of remaining life of the structural elements influences the decisions of maintenance engineers (checking intervals, corrections, and replacements).The fatigue crack growth rate, which determine the fatigue life of the components after crack initiation need to be experimentally and theoretically investigated. In this study, fatigue crack growth tests were conducted under constant amplitude loading at a stress ratio of 0.1, using three-point bend (TPB) specimens of ASTM A533 steel material. For the simulation part of this study, three fatigue crack growth models, i.e. the Paris, modified Forman and Austen were examined. None of the models has a fit for the fatigue crack growth rate data in a similar behaviour compared to others. The modified Forman model provided a closer fit than the Paris model with respect to the experimental results. However, the Austen model provided the best fit to the fatigue crack growth rate data as compared with the other two models. Therefore, this model is suggested for use in critical applications.