15 research outputs found
High intensity tapping regime in a frustrated lattice gas model of granular compaction
In the frame of a well established lattice gas model for granular compaction,
we investigate the high intensity tapping regime where a pile expands
significantly during external excitation. We find that this model shows the
same general trends as more sophisticated models based on molecular dynamic
type simulations. In particular, a minimum in packing fraction as a function of
tapping strength is observed in the reversible branch of an annealed tapping
protocol.Comment: 5 pages, 4 figure
From crystal to amorphopus: a novel route towards unjamming in soft disk packings
It is presented a numerical study on the unjamming packing fraction of bi-
and polydisperse disk packings, which are generated through compression of a
monodisperse crystal. In bidisperse systems, a fraction f_+ = 40% up to 80% of
the total number of particles have their radii increased by \Delta R, while the
rest has their radii decreased by the same amount. Polydisperse packings are
prepared by changing all particle radii according to a uniform distribution in
the range [-\Delta R,\Delta R]. The results indicate that the critical packing
fraction is never larger than the value for the initial monodisperse crystal,
\phi = \pi/12, and that the lowest value achieved is approximately the one for
random close packing. These results are seen as a consequence of the interplay
between the increase in small-small particle contacts and the local crystalline
order provided by the large-large particle contacts.Comment: two columns, 14 pages, 12 figures, accepted for publication in Eur.
Phys. J.