A Novel Discrete Element Method for Smooth Polyhedrons and Its Application to Modeling Flows of Concave-Shaped Particles

The smooth polyhedral model has been commonly used to construct non-spherical particles with smooth surfaces, whereas it is mainly constrained to numerical simulations involving concave-shaped particles. This constraint arises from the limitations imposed by the contact algorithm. In this study, the contact detection between smooth polyhedrons is simplified to that between dilated triangular elements, and a discrete element method for concave polyhedral particles with smooth surfaces is developed. Subsequently, an automatic mesh simplification algorithm is established to enhance the computational efficiency without compromising accuracy. In validating the smooth polyhedral model, the simulation results of a hexahedron colliding with a plane are found to agree favorably with the experimental results. Then, the elastic collisions between the convex and concave particles are analyzed, and the total kinetic energy before and after the particle collision remains unchanged. Furthermore, the influences of particle morphology on the packing fraction, flow fluctuation, flow rate, mixing rate, velocity distribution, and system energy in hoppers and rotating drums are analyzed, revealing the underlying flow characteristics of concave polyhedral granular materials with smooth surfaces.