Bridging strategy between microscopic and macroscopic crack growth simulations to predict fatigue strength of steels

A strategy for bridging microscopic and macroscopic crack-growth simulations is proposed for efficiently and accurately predicting the fatigue strength of steels by integrating the multiscale model and the concept of the bridging method. Validation by comparing the experimental results of macro-crack specimens and the numerical results of the multiscale model shows a reduction of more than 90% in the numerical costs with the proposed strategy compared to the multiscale model. Only 4.2% and 2.7% errors in fatigue life for the two macro-crack specimens under the maximum loading cases are achieved, whereas no errors in fatigue limits are observed using the proposed strategy, compared to the multiscale model. The accuracy and efficiency of predicted results indicate that the proposed strategy can serve as a robust foundation for evaluating the fatigue failure behaviour of thick components/structures in engineering applications.