Study of the effect of vibrocompaction modes, shape of particles and their size distribution on packing density

The results have been described of experimental studies of the influence of vibrocompaction modes, shape of particles and their size distribution on the relative package density. The glass spheres with diameters distributed from 0.4 to 0.9 mm and from 0.63 to 0.8 mm, containing a fraction of nonspherical particle inclusions of about 30 % have been taken as the research object. Also in the experiments the powder was used of electrocorundum with particle size of 0.63-0.8 mm. This choice was aimed at bringing the particles characteristics to those of a real granular material and no separation of particles into spherical and non-spherical was planned. The experiments on vibrating packing have been performed with the help of dynamic "Revolution" powders rheometer. The modes of compaction vibration varied over a wide range of frequencies and amplitudes: from 5 to 475 Hz and from 106 to 1062 µm, respectively. The vibration frequency has shown to exert a greater effect on relative density as compared to that of the amplitude. The dependence of relative density on vibration frequency exhibits several local maxima for all vibration amplitudes. The maximum relative packing density of 0.64 ... 0.65 is achieved at a combination of high amplitude (850, 1062 µm ) and high frequency (300 ... 350 Hz). Effect of granulometric composition on relative packing spheres density is less pronounced than that of the vibration frequency and approximately equals to than of the amplitude. Increasing the deviations of the particles size is accompanied by increasing frequencies leading to maximum packing density. The particles shape affects the level of packing density, thereby remaining the same character of dependence of relative density on vibration frequency for both spherical and non-spherical particles of similar particle size distribution. (paper)