Discrete crystal plasticity modelling of slip-controlled cyclic deformation and short crack growth under low cycle fatigue

For metals under fatigue, microplastic strain localisation leads to the formation of discrete slip bands, which contributes to the initiation and propagation of short cracks. In this paper, a discrete slip band model is introduced to investigate the slip-controlled cyclic deformation and short crack growth in a single crystal alloy. In conjunction with crystal plasticity and normal factor-based critical resolved shear stress, finite element simulations demonstrated the success of the discrete model in describing orientation-dependent cyclic stress-strain responses. The proposed approach is also capable of predicting slip-controlled short crack growth, based on element deletion technique and individual cumulative shear strain criterion.