Strain-induced instability and fatigue damage initiation in viscoelastic materials

Abstract

This study investigated the characteristics of the amorphous material fatigue model proposed by Kurotani et al. concerning the rate/time-dependent material instability and the fatigue damage initiation process. Stress relaxation simulations showed that, in this model, two mechanisms compete, one of which increases the density fluctuations by mechanical deformation and the other decreases them over time. In fatigue simulations, the density fluctuation gradually becomes nonuniform, resulting in damage generation. During this process, the density fluctuations form a band-like pattern in the principal-stress direction, and the equivalent strain forms a pattern along the shear direction. We demonstrated that the model could provide mesoscopic insights into the mechanical properties of amorphous materials.