ADAPTIVE PHASE-FIELD CONCURRENT MULTISCALE METHOD FOR EFFICIENT SIMULATION OF QUASI-BRITTLE FRACTURE

An adaptive phase-field concurrent multiscale method for efficient simulation of quasi-brittle fracture is presented. In this method, the analysis model is first subjected to coarse mesh discretization and the corresponding damage phase field calculation analysis. Then, adaptive dynamic local mesh refinement is performed for the coarse scale elements exceeding the given damage threshold during the iterative process. The locally refined mesh is defined as the local subdomain, the outermost coarse elements of the refined mesh, and the coarse elements without refinement are defined as the global subdomain. The variant s-version method is used to realize the direct coupling connection of mismatched meshes in different subdomains and the application of the continuity condition of field variables on the global-local subdomain interface. The division of the local subdomain, the global subdomain, and their overlapping domain are dynamically updated with the crack propagation path in the proposed method. The generation of the global-local computing mesh has great flexibility without the need for scale separation, which provides a more concise and flexible implementation for multiscale phase field adaptive simulation. The proposed method overcomes the extra burden and complexity of field variable conversion between coarse and fine scales, imposition of continuity conditions, and program implementation in existing phase field multiscale methods, which can be easily applied to the analysis on damage-fracture behavior of quasi-brittle structures. Typical examples verify the correctness, robustness, and advantages of the method.