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dc.contributor.author Zhang, J
dc.contributor.author Majmudar, TS
dc.contributor.author Sperl, M
dc.contributor.author Behringer, RP
dc.date.accessioned 2011-06-21T17:27:16Z
dc.date.issued 2010-07-07
dc.identifier.citation Soft Matter, 2010, 6 (13), pp. 2982 - 2991
dc.identifier.issn 1744-683X
dc.identifier.uri http://hdl.handle.net/10161/4125
dc.description.abstract This paper focuses on the nature of jamming, as seen in two-dimensional frictional granular systems consisting of photoelastic particles. The photoelastic technique is unique at this time, in its capability to provide detailed particle-scale information on forces and kinematic quantities such as particle displacements and rotations. These experiments first explore isotropic stress states near point J through measurements of the mean contact number per particle, Z, and the pressure, P as functions of the packing fraction, . In this case, the experiments show some but not all aspects of jamming, as expected on the basis of simulations and models that typically assume conservative, hence frictionless, forces between particles. Specifically, there is a rapid growth in Z, at a reasonable which we identify with as c. It is possible to fit Z and P, to power law expressions in - c above c, and to obtain exponents that are in agreement with simulations and models. However, the experiments differ from theory on several points, as typified by the rounding that is observed in Z and P near c. The application of shear to these same 2D granular systems leads to phenomena that are qualitatively different from the standard picture of jamming. In particular, there is a range of packing fractions below c, where the application of shear strain at constant leads to jammed stress-anisotropic states, i.e. they have a non-zero shear stress, τ. The application of shear strain to an initially isotropically compressed (hence jammed) state, does not lead to an unjammed state per se. Rather, shear strain at constant first leads to an increase of both τ and P. Additional strain leads to a succession of jammed states interspersed with relatively localized failures of the force network leading to other stress-anisotropic states that are jammed at typically somewhat lower stress. The locus of jammed states requires a state space that involves not only and τ, but also P. P, τ, and Z are all hysteretic functions of shear strain for fixed . However, we find that both P and τ are roughly linear functions of Z for strains large enough to jam the system. This implies that these shear-jammed states satisfy a Coulomb like-relation, τ = μP. © 2010 The Royal Society of Chemistry.
dc.format.extent 2982 - 2991
dc.language.iso en_US en_US
dc.relation.ispartof Soft Matter
dc.relation.isversionof 10.1039/c000147c
dc.title Jamming for a 2D granular material
dc.title.alternative en_US
dc.type Journal Article
dc.description.version Version of Record en_US
duke.date.pubdate 2010-00-00 en_US
duke.description.endpage 2991 en_US
duke.description.issue 13 en_US
duke.description.startpage 2982 en_US
duke.description.volume 6 en_US
dc.relation.journal Soft Matter en_US
pubs.issue 13
pubs.organisational-group /Duke
pubs.organisational-group /Duke/Trinity College of Arts & Sciences
pubs.organisational-group /Duke/Trinity College of Arts & Sciences/Physics
pubs.publication-status Published
pubs.volume 6
dc.identifier.eissn 1744-6848

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