An enhanced adaptive coupling strategy of peridynamics and finite element method via variable horizon approach for simulating quasi-static fracture problems

An enhanced adaptive coupling method of peridynamic (PD) theory and the finite element method (FEM) is performed that combines the advantages of both approaches and can be used to simulate quasi-static fracture problems. In the proposed model, PD is used to simulate crack initiation and propagation, whereas the FEM is used to simulate domains without damage to improve efficiency. The influence of ghost forces is reduced by introducing a transition subregion with a variable horizon, thereby significantly improving the accuracy of the model, which is verified by application to a plane stress problem. The conventional coupling model requires prepartitioning of the solution domain, which is difficult to achieve when modeling certain problems, such as the initiation of cracks at unknown locations. Hence, the adaptive conversion criterion is introduced to ensure that subregions automatically evolve as cracks grow, thereby obviating the need for prior knowledge of crack propagation paths. The proposed model is applied to three standard laboratory tests of quasi-static fracture and its performance is validated by the good agreement of its results with reference solutions or experimental observations. The model accurately simulates complex fracture problems involving crack initiation, irregular crack propagation, and crack coalescence.