Abstract
Random packings of non-spherical granular
particles are simulated by combining mechanical contraction
and molecular dynamics, to determine contact numbers as a
function of density. Particle shapes are varied from spheres
to thin rods. The observed contact numbers (and packing
densities) agree well with experiments on granular packings.
Contact numbers are also compared to caging numbers calculated
for sphero-cylinders with arbitrary aspect-ratio. The
caging number for rods arrested by uncorrelated point contacts
asymptotes towards γ = 9 at high aspect ratio, strikingly
close to the experimental contact number C ≈ 9.8
for thin rods. These and other findings confirm that thin-rod
packings are dominated by local arrest in the form of truly
random neighbor cages. The ideal packing law derived for
random rod–rod contacts, supplemented with a calculation
for the average contact number, explains both absolute value
and aspect-ratio dependence of the packing density of randomly
oriented thin rods.
Original language | Undefined/Unknown |
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Pages (from-to) | 169-177 |
Number of pages | 9 |
Journal | Granular Matter |
Volume | 11 |
Publication status | Published - 2009 |