A multi-point constraint-based coupled PD-FEM model for high-cycle fatigue simulation: enhanced surface effect corrections

This study proposes a direct coupled approach integrating Bond-Based Peridynamics (BBPD) and the Finite Element Method (FEM) for high-cycle fatigue (HCF) simulations. The proposed method achieves direct coupling without shared nodes through the use of Multi-Point Constraint (MPC), incorporating surface effect correction to adjust the constitutive behavior of PD bonds near the PD-FEM interface. First, static analyses of cantilever beam models were performed both without and with three different surface effect correction methods. Comparison with FEM results confirmed the necessity of surface effect correction at the interface and demonstrated the effectiveness of the coupling strategy in two-dimensional (2D) scenarios. Among the correction methods evaluated, the Energy Density Method (EDM) proved to be the most effective. The static response of a three-dimensional (3D) bar model was also analyzed and compared with the FEM solution, further validating the coupling method’s applicability to 3D problems. Subsequently, HCF crack propagation simulations were conducted on a compact tension (CT) specimen and a T-shaped welded joint. The accuracy of the PD fatigue model was validated through comparisons with test results. Finally, the coupled PD-FEM model was applied to HCF analysis of the CT specimen and T-joint. The close correlation between the simulation and experimental outcomes confirms the model’s capability for component-level HCF simulations.