Analysis of short-range contact forces in peridynamics endowed with an improved nonlocal contact model

The motion and deformation laws of multi object interactions in computational models depend on contact algorithms. However, research on the peridynamic contact problem is limited. In this paper, in order to effectively prevent non-physical intrusion during contact, the inherent problems of the contact algorithm in peridynamic discrete models are analyzed, and a force boundary contact method using nonlinear contact stiffness is proposed. Through numerical calculations and geometric analysis of the peridynamic discrete model, the characteristics and reasons for the variation of contact force in the peridynamic contact model under fixed contact stiffness are discovered. To address the nonlinear reduction of contact force and potential non-physical intrusion in the peridynamic contact model, a force boundary peridynamic contact method is proposed by introducing a nonlinear changing contact stiffness function. Then the characteristics of contact force variation in different kinds of contact functions are studied and the parameter setting of contact functions is discussed. The results show that this method can effectively prevent non-physical intrusion and the calculation error is acceptable. This paper lays a foundation for further research on contact constitutive model based on Peridynamic framework.