An experimental study of packing of ellipsoids under vibrations

Packing of ellipsoidal particles with a range of aspect ratios is experimentally studied under vibration conditions. The effects of operational conditions such as dropping heights, feeding methods, and vibration modes on packing density are investigated systematically. The results indicate that packing density first increases with dropping height, and then tends to be a certain value when dropping height is over 180d_v. The relationship between packing density and aspect ratios gives an M-shaped curve, irrespective of operational conditions. This is also consistent with literature observations. The packing density obtained by batch-wised feeding method is higher than that obtained by total feeding method, especially when three-dimensional vibration is applied. The packing density increases with the increase of vibration frequency and then decreases, i.e. there is an optimum frequency to achieve maximum packing density. The optimum frequency varies with vibration dimensions. The local particle orientation order can be found under three-dimensional vibration with proper amplitude and frequency.