Serration effects on interfacial cracks

Abstract

To investigate the effect of serrations in an interfacial crack between dissimilar materials, we introduce into the Finite Element (FE) framework a unit cell (UC) at microscale. By assigning material-specific properties to these unit cells, we can model various serration profiles and distributions and calculate their effect on the mixed-mode stress intensity factor (SIF), including its magnitude and phase angle. The simulation demonstrates that serration profoundly changes the local behavior of an interfacial crack. The serrations decrease the SIF in mode I, increase it in mode II, and, when the serration's height-towidth ratio increases, the mode mixity SIF increases as well. We find that sparse serration confines variation in the SIFs to the local peaks and that dense serrations cause widespread undulations in the SIF's magnitude and phase angle.