Abstract: Smoothed particle hydrodynamics (SPH) is a Lagrangian meshless method, which has remarkable advantages in numerical analysis of solids with extremely large deformation. The present paper deals with SPH simulation of large solid deformation involving frictional contact interface. A new pure smoothed particle PTVD (point-to-volume discrete) contact algorithm is developed based on the FPM (finite particle method) particle interpolation, which is an alternative SPH formulation for improving the interpolation accuracy near boundaries. The PTVD contact algorithm transforms equivalently the interface contact force into the external interactive forces between particles near the contact interface. To be specific, the particles modelling either body in contact are grouped as master particles and slave particles with respect to the feature of the contact interface. For each slave particle near the contact point, the relative position is determined according to the amount of master particles contained in the influence domain of that particle, and the normal contact force is then calculated considering the contact stiffness. The shear contact force is determined considering the relative shear velocity between two particle groups within the influence domain and the friction of the interface. The proposed PTVD contact algorithm highlights the nonlocal characteristics of the SPH methods and avoids the complex algorithm for identifying and accurately describing the interface. Following the verification through the classic contact and friction examples, the PTVD algorithm is applied to the SPH analysis of quasi-static collapse of cohesionless granular soil and projectile penetration into soft soil. The results demonstrate the effectiveness and applicability of the proposed contact algorithm in SPH modelling of frictional contact problems.

Key words: smoothed particle hydrodynamics (SPH) method, frictional contact interface, large deformation, point-to-volume discrete (PTVD) contact algorithm