Adaptive phase-field modeling of three-dimensional thermally-induced brittle fracture in COMSOL

This work proposes an adaptive thermomechanical phase-field framework for simulating three-dimensional (3D) thermally-induced fracture in brittle materials. Adaptive mesh refinement is performed via the COMSOL application programming interface (API), using a user-defined phase-field threshold as the refinement indicator. COMSOL’s built-in adaptive meshing produces a locally refined mesh without hanging nodes. A staggered iteration scheme is adopted to ensure computational robustness of the fracture phase-field framework. To further improve computational efficiency in 3D fracture problems, the restarted generalized minimum residual (GMRES) method, combined with smoothed aggregation algebraic multigrid (SAAMG), is adopted as an iterative linear system solver. Through the analysis of three numerical examples, the accuracy and efficiency of the present framework can be validated. The open-source model enables users without programming experience to simulate fractures in a multiphysics environment.