General polygon mesh discrete element method for arbitrarily shaped particles and complex structures based on an energy-conserving contact model

Interactions between irregular particles and structures always exist in the natural environment and industrial production process. For the desired simulation into the dynamic behaviors of arbitrarily shaped particles in complex structures, a general polygon mesh discrete element method (DEM) is developed based on the general energy-conserving contact theory. Within this method, a complete normal contact model for a contact pair with a complex contact region is proposed when the elastic strain energy density is utilized to specify a contact energy function. Since the shape of both complex particles and structures are uniformly constructed by polygon meshes, a unified contact detection implementation performed in this method is introduced in detail. This proposed method is characterized by the universal and uniform models of shape construction, contact detection, and contact force calculation for both particle-particle contact pairs and particle-structure contact pairs. To qualitatively demonstrate the conservation and robustness of the method, a set of validations or simulations considering the differently shaped particles, such as convex particles, concave particles, and particles with surface asperities, are applied. It is concluded from these validations or simulations that the general polygon mesh DEM and the corresponding proposed models are valid tools for research into the behavior of granular materials in complex structures.