Volume 78, Number 4, May 2007
Article Number 44004
Number of page(s) 4
Section Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
Published online 10 May 2007
EPL, 78 (2007) 44004
DOI: 10.1209/0295-5075/78/44004

Phase transition in a static granular system

Matthias Schröter1, Sibylle Nägle1, Charles Radin2 and Harry L. Swinney1

1  Physics Department and Center for Nonlinear Dynamics, University of Texas at Austin - Austin, TX 78712, USA
2  Mathematics Department, University of Texas at Austin - Austin, TX 78712, USA

received 3 February 2007; accepted in final form 11 April 2007; published May 2007
published online 10 May 2007

We find that a column of glass beads exhibits a well-defined transition between two phases that differ in their resistance to shear. Pulses of fluidization are used to prepare static sedimented states with well-defined particle volume fractions $\phi $ in the range 0.57$\hbox{--} $0.63. The resistance to shear is determined by slowly inserting a rod into the column of beads. Force measurements and bed height measurements both indicate that the transition occurs at $\phi =0.60$ for a range of speeds of the rod.

45.70.Cc - Static sandpiles; granular compaction .
81.05.Rm - Porous materials; granular materials .
45.70.-n - Granular systems .

© Europhysics Letters Association 2007