Simulating frictional contact in smoothed particle hydrodynamics

Smoothed Particle Hydrodynamics (SPH) is a powerful tool for large deformation computation of soil flow. However, the method to simulate frictional contact in the framework of SPH is still absent and needs to be developed. This paper presents an algorithm to simulate frictional contact between soil and rigid or deformable structure in the framework of SPH. In this algorithm, the computational domain is divided into several sub-domains according to the existing contact boundaries, and contact forces are used as bridges of these sub-domains to fulfill problem solving. In the process of the SPH discretization for governing equation of each sub-domain, the inherent problem of boundary deficiency of SPH is handled properly. Therefore, the particles located at contact boundary can have precise acceleration, which is critical for contact detection. Then, based on the assumption that the SPH particle of soil can slightly penetrate into the structure, the contact forces along normal and tangential directions of the contact surface are computed by momentum principle, and the frictional force is modified if sliding occurs. Compared with previous methods, in which only particle-to-particle contact is considered or frictional sliding is just ignored, the method proposed in this study is more efficient and accurate, and is suitable for simulating interaction between soft materials and rigid or deformable structures, which are very common in geotechnical engineering. A number of numerical tests have been carried out to verify the accuracy and stability of the proposed algorithm, and the results have been compared with analytical solutions or FEM results. The consistency obtained from these comparisons indicates that the algorithm is robust and can enhance the computing capability of SPH.