Multiscale modelling strategy for predicting fatigue lives and limits of steels based on a generalised evaluation method of grain boundaries effects

Multiscale modelling strategy for predicting fatigue lives and limits of steels is proposed based on a generalised method for evaluating grain boundaries' (GBs) effects on fatigue crack growth. The proposed strategy is a modification of our previous works that extends the applicability from only low-grade ferrite steels to high-grade bainite steels. A microstructure model was developed considering distances between GBs and misorientations between adjacent grains. The strategy was validated by comparison with experiments using two ferrite-pearlite and one bainite steels; results indicate the strategy predicted fatigue lives and limits of steels with microstructures from coarse ferrite to fine bainite grains.

Automated summary

A multiscale modelling strategy is proposed for predicting fatigue lives and limits of steels, which is based on a general method for evaluating the effects of grain boundaries on fatigue crack growth. The strategy is validated through experiments on different types of steels and shown to accurately predict fatigue lives and limits.