Bulletin of the American Physical Society
APS March Meeting 2011
Volume 56, Number 1
Monday–Friday, March 21–25, 2011; Dallas, Texas
Session H13: Focus Session: Jamming Theory and Experiment I
8:00 AM–11:00 AM,
Tuesday, March 22, 2011
Sponsoring Unit: GSNP
Chair: Mark Shattuck, City College of New York
Abstract ID: BAPS.2011.MAR.H13.9
Abstract: H13.00009 : Shear-jammed states in granular materials*
10:00 AM–10:12 AM
Preview Abstract Abstract
(Indiana University - Purdue University Fort Wayne)
For frictionless particles with purely repulsive interactions, there is a critical packing fraction $\phi_J$ below which no jammed states exist. Experiments by Zhang \& Behringer on physical granular systems show jammed states in the regime of $\phi < \phi_J$ can be created by the application of shear stress. Compared to the states above $\phi_J$, the shear-jammed states are mechanically more fragile, but they resist shear. These shear-jammed states cannot exist under isotropic stress. Rather, their formation require the anisotropic contact network as a backbone which is created by an applied shear stress. The anisotropic components of the stress tensor and contact network fabric tensor form a classic hysteresis loop suggesting an analogy to ferromagnetic behavior and critical phenomena. These new states must be incorporated into a more general jamming picture. We also carry out extensive analysis on shear-jammed states and find local stress fluctuations are controlled by their respective global pressures. To explain the scaling of local stress fluctuations, we construct a mean-field model based on the entropy of stress configurations.
*Supported by NSF-DMR0905880 and NSF-DMR0906908.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.H13.9
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