Numerical studies on thermal shock crack branching instability in brittle solids

•Crack branching instability in brittle ceramic specimens under thermal shocks is investigated.•New coupled thermal mechanical bond-based peridynamics enriched with shear deformation is proposed.•Three different types of thermal shock cracking patterns are captured using the proposed numerical model.•Crack propagation speed is strongly affected by thermal gradient. The new weakly coupled thermal mechanical bond-based peridynamic model enriched with shear deformation is developed to study crack propagation and branching instability in brittle solids subjected to thermal shocks. First, the proposed numerical model is validated via comparisons with the classical finite element method (FEM) results. Next, thermal shock crack branching instability in brittle ceramic disks under infrared radiation heating is investigated using the proposed numerical model. Three different types of thermal shock cracking patterns, including no crack branching, crack branching inside heating region and crack branching outside heating region, can be captured by using the proposed numerical model, which are consistent with the previous experimental and numerical results. Effects of heat flux density, heating size, pre-existing notch length, horizon size and nonlocal ratio on thermal shock cracking patterns, crack propagation speed, strain energy distributions around crack tips and crack branching angle are also systematically investigated. The mechanism of thermal shock crack branching instability is revealed. Finally, some characteristics of thermal shock crack branching instability in brittle solids are discussed and summarized.