Numerical simulations of impact breakage of a spherical crystalline agglomerate

A numerical study of the micromechanics of impact of a sub-millimetre sized crystalline agglomerate with a target wall has been carried out using granular dynamics (or discrete element) simulations. The agglomerate, a spherical face-centred cubic array of ca. 8000 autoadhesive elastic primary particles, was assigned different interparticle bond strengths and impacted at different velocities. The effect of impact velocity and bond strength on the evolution of various impact parameters is reported. During loading, a shear-induced pattern of partially fractured planes was created which was dictated by the geometry of the impact area and the orientation of the packing planes. During unloading, fracture patterns were observed to be sub-sets of the preformed shear-induced weakened planes. The fragment size and mass distributions after impact have also been examined and related to the intrinsic properties of the agglomerate and the impact parameters.