Improvements in Fracture Parameter Evaluation of Mixed-Mode Problems Using Modified Peridynamics

Peridynamics (PD), which underpins many meshfree methods, has found widespread applications in fracture mechanics. However, its accuracy in simulating shear behavior remains limited, particularly for mixed-mode fracture problems. To address this, we propose a modified formulation of ordinary state-based PD (OSPD) that incorporates bond rotation behavior, including shear deformation and rigid body rotation (RBR). Using the peridynamic differential operator, the stress-free RBR component is identified and removed from the total displacement. The enhanced formulation is validated through classical benchmark problems, with stress intensity factors evaluated using the interaction integral method. Numerical results demonstrate excellent agreement with reference solutions from the literature and the original OSPD model, confirming the improved accuracy of the modified OSPD model. Notably, the modified model exhibits superior performance in simulating shear deformation, establishing its reliability in mixed-mode fracture analysis.