Shearing of frictional sphere packings

¹ Max Planck Institute for Dynamics and Self-Organization - Göttingen, Germany, EU
² Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin - Austin, TX, USA
³ Department of Mathematics, University of Texas at Austin - Austin, TX, USA

^a jean-francois.metayer@ds.mpg.de

Received: 6 January 2011
Accepted: 23 February 2011

Abstract

We measure shear response in packings of glass beads by pulling a thin, rough, metal plate vertically through a bed of volume fraction φ, which is set, before the plate is pulled, in the range from 0.575 to 0.628. The yield stress is velocity independent over 4 decades and increases exponentially with φ, with a transition at φ ≈ 0.595. An analysis of the measured force fluctuations indicates that the shear modulus is significantly smaller than the bulk modulus.