DEM simulation on random packings of binary tetrahedron-sphere mixtures
The random packings of binary tetrahedron-sphere mixtures were numerically reproduced by DEM simulations. The influences of particle shape (characterized by eccentricity ζ and height ratio η), particle size, and composition on the packing density of binary tetrahedron-sphere mixtures were systematically investigated. The properties of equivalent packing diameter are identified by both macroscopic and microscopic parameters. The results show that the equivalent packing diameter of tetrahedra is independent of the particle shape (ζ and η) deviation. The minimal specific volume variations ΔV are negative for each case with the size ratio ranging from 0.5 to 1 caused by the shape particularity of tetrahedra. The overall mean coordination number (CN) obtained at r = 1 (here, r = ds/dte, ds and dte are respectively sphere diameter and equivalent volume sphere diameter of tetrahedral particles) is almost identical and does not change with the variation of composition. The mean stress analysis shows that the equivalent packing diameter is not only universal for the microstructure parameters, but also for the mechanical properties of tetrahedron-sphere binary packings.
Keywords: Binary packing, Tetrahedron and sphere mixture, Equivalent packing diameter, DEM simulation, Microscopic property