Development of multi-phase-field crack model for crack propagation in polycrystal

It is vitally important to ensure the safety of brittle materials. Therefore, it is essential to deeply understand the interaction of the material's microstructure and crack propagation. In this study, we constructed a multi-phase-field crack model which can express crack propagation in polycrystal. To evaluate the basic characteristics of the developed model, we performed two-dimensional crack propagation simulations in a bicrystal where a crack enters an inclined grain boundary by changing the ratio of the grain boundary energy to the crack surface energy. As a result, it is confirmed that the model can reasonably determine the crack path, depending on those conditions. Furthermore, by performing crack propagation simulations in a polycrystal, it is concluded that the model can properly express transgranular and intergranular cracks.