Modeling of coupled thermo-mechanical crack propagation in brittle solids using adaptive phase field method with scaled boundary finite element method

Complex crack patterns caused by thermally induced stresses commonly occur during thermal shrinkage in brittle materials, such as ceramic. Modeling the propagation of complex cracks can be tedious, computationally intensive and time consuming when multiple cracks initiate simultaneously. In this paper, the coupled thermomechanical Phase Field Model (PFM) is adopted, which facilitates the treatment of crack initiation, growth, bifurcation and coalescence in a unified framework. However, to represent the crack, the PFM requires a very fine mesh which increases the computational burden especially when the crack locations are not known as a priori. Aiming to efficiently reveal the crack morphogenesis and evolution in brittle material subjected to thermal shock, a space adaptive PFM is developed by refining the elements in the vicinity of crack propagating path on the fly, which reduces the number of elements and reduces the computational cost eventually. The Scaled Boundary Finite Element Method is applied with the quadtree mesh in this work to achieve the adaptive approach in the PFM as it is highly complementary. The presented numerical examples are showing good agreement with experiments and other results available in the literature, further, higher computational efficiency is achieved by employing the adaptive approach.