A simulation study of the effects of dynamic variables on the packing of spheres

The packing of uniform spheres has been studied by means of Discrete Element Method with special reference to variables affecting the packing dynamics, with the results analysed in terms of packing density, radial distribution function (RDF) and coordination number. It is shown that packing density increases with dropping height and restitution coefficient, and decreases with deposition intensity and friction coefficient, which is consistent with previous experimental findings. Both RDF and coordination number distribution vary with these variables, in line with packing density. For a packing of high density, it has a clear split second peak in its RDF, like that observed for the dense random packing. However, as packing density decreases, the first component of the split second peak will gradually vanish, giving an RDF more comparable to those observed in a sequential addition simulation. Mean coordination number can be correlated with packing density; it increases with dropping height and restitution coefficient, and decreases with deposition intensity and friction coefficient.