Abstract
Granular processes in nature and industry often involve complex quasistatic or dynamic flows of various particle shapes and frictional properties. Although empirical approaches have been developed for such flows, advanced particle dynamics simulations can be used for detailed sensitivity analysis of their scaling behavior as a function of system parameters or to connect their behavior to the microstructure. In this work, extensive simulations are used in 3D to study the effects of polyhedral particle shape on quasi-static granular flows under fully periodic boundary conditions and dynamic cascading flows in rotating drums. Orthotropic elastic moduli under triaxial compression are expressed as a function of the contact network anisotropy and a constraint number accounting for different types of contacts between polyhedra. Various fabric variables and force transmission are also analyzed and compared with spherical particle packings. In rotating drums, the cascading flow regime is investigated for a broad range of parameter values and shown to be governed by a unique dimensionless scaling parameter that combines all system parameters such as rotation speed, filling degree and particle size. It is also shown that the proposed scaling is consistent with a particle coarsening approach. Finally, the impact-induced breakage of a single particle is modeled by means of a novel fracture model based exclusively on fracture energy. The fragment shapes and sizes are studied systematically and the distribution of fragment masses is found to be a power-law function with an exponent depending on the fracture energy.