Onset of mechanical stability in random packings of frictional spheres.
Using sedimentation to obtain precisely controlled packings of noncohesive spheres, we find that the volume fraction phiRLP of the loosest mechanically stable packing is in an operational sense well defined by a limit process. This random loose packing volume fraction decreases with decreasing pressure p and increasing interparticle friction coefficient mu. Using x-ray tomography to correct for a container boundary effect that depends on particle size, we find for rough particles in the limit p-->0 a new lower bound, phiRLP=0.550+/-0.001.
Jerkins
Melissa
M
Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA.
Schröter
Matthias
M
Swinney
Harry L
HL
Senden
Tim J
TJ
Saadatfar
Mohammad
M
Aste
Tomaso
T