Discrete element method dynamic simulation of icosahedral particle packing under three-dimensional mechanical vibration

Abstract

Packing densification of monosized regular icosahedral particles under three-dimensional mechanical vibration has been simulated by the discrete element method (DEM). The effects of the vibration conditions and container size on packing densification were systematically investigated. In addition to the macroscale properties (packing density and porosity), the microscale properties, such as the coordination number (CN), radial distribution function (RDF), particle contact type, particle orientation distribution, and stresses/forces, in random loose packing (RLP) and random close packing (RCP) were also characterized and analyzed. The results show that transformation of icosahedral particle packing from RLP to RCP can be realized by properly controlling the vibration conditions. The maximum random packing density without the wall effect reaches 0.7078. Microscale property analysis shows that the average CN increases after vibration. The RDF curves contain two clear peaks for RLP and three for RCP. From RLP to RCP, the probability of face to face contact between two particles increases, while the probabilities of edge to edge, edge to face, and face to vertex contact decrease. The orientation correlation functions indicate the randomness of the vibrated packing structure. In addition, more uniform force and stress distributions are observed within the dense packing structure.