Numerical simulation of the impact-breakage behavior of non-spherical agglomerates

Abstract

A numerical study of the breakage behavior of non-spherical agglomerates is presented in this paper. Six agglomerates of various shapes (e.g., spherical, regular tetrahedral, cuboidal, regular octahedron, regular dodecahedron and regular icosahedrons) with different sphericities are examined using discrete element method (DEM) simulations. First, appropriate parameters for the simulation model are obtained based on uniaxial compressive experiments and single coal rock impact test. Then, a series of numerical simulations is performed to examine the breakage behavior of the non-sphere agglomerates produced. The study shows that better breakage performance can be obtained with a higher impact velocity. The collision behaviors of the non-spherical bodies are relatively more complex compared to those of spherical bodies. Detailed examinations of the evolutions of the damage ratio and wall force indicate that the size of the contact area plays an important role in the breakage behavior of the agglomerates. Most of the maximum wall forces and final damage ratios show a decreasing trend when the face-impact, edge-impact and vertex-impact modes are used. However, these values are still significantly larger than those of spherical agglomerates. The simulation results show that the debris and fragments created after the agglomerates fracture have independent shapes and impact modes. The value of the detected two features decrease as sphericity increases when the face-impact mode is used but increase with the sphericity when the edge- and vertex-impact modes are used. Minor changes in sphericity can result in significantly different fracture patterns in non-spherical agglomerates.