Development of Fatigue Life Prediction Program for Multiple Surface Cracks

The objective of this paper is to develop a computational model and a software for predicting the fatigue propagation of collinear multiple surface cracks under constant-amplitude and variable-amplitude loading. After examining fatigue crack growth rate data for compact tension (CT) specimens and single surface crack specimens, an empirical equation is proposed for the prediction of fatigue life in a multiple surface crack geometry. The accuracy of the proposed model is verified using a life prediction computer program. The predictions are compared with the results from several case studies to check the accuracy of the proposed model and to verify the usefulness of the developed program. Good agreement is observed between the numerical results based on the proposed model and the published experimental data.