Thermally-induced fracture analysis of polycrystalline materials by using peridynamics

Polycrystalline materials are widely utilized in engineering fields. In this study, peridynamic (PD) models are developed for the first time in the literature to investigate thermally-induced fracture phenomenon for cubic polycrystals and ceramic made of different materials. After validating the current model, the influences of the grain size, grain boundary strength and composition of the materials on the fracture behavior are analyzed. Two different types of pre-existing cracks, i.e. vertical and horizontal, are considered. The effect of grain size is much more obvious for ceramic materials and crack branching is observed for both vertical and horizontal crack cases. Grain boundary strength has a significant influence on crack behaviour. For weaker grain boundaries intergranular fracture pattern is observed whereas for stronger grain boundaries transgranular crack pattern is more dominant. Crack branching is much more significant when the silicon carbide ratio is higher due to the difference in coefficients of thermal expansion of two different materials. By comparing with the reference results available in the literature similar fracture features are obtained.