Phase transition in a static granular system

Abstract

We find that a column of glass beads exhibits a well-defined transition\nbetween two phases that differ in their resistance to shear. Pulses of\nfluidization are used to prepare static states with well-defined particle\nvolume fractions $\\phi$ in the range 0.57-0.63. The resistance to shear is\ndetermined by slowly inserting a rod into the column of beads. The transition\noccurs at $\\phi=0.60$ for a range of speeds of the rod.\n