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DY: Dynamik und Statistische Physik

DY 43: Granular matter II

DY 43.2: Vortrag

Donnerstag, 27. März 2003, 11:30–11:45, G\"OR/229

Directed force chain networks and pseudo-elastic continuum theories for dense granular packings — •Matthias Otto¹, Jean-Philippe Bouchaud², Philippe Claudin³, and Joshua E.S. Socolar⁴ — ¹Institut für Theoretische Physik, Universität Göttingen, Bunsenstr. 9, D-37075 Göttingen, Germany — ²Service de Physique de l’Etat Condensé, CEA-Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France — ³Laboratoire des Milieux Désordonnés et Hétérogènes (UMR 7603), 4 place Jussieu – case 86, 75252 Paris Cedex 05, France — ⁴Department of Physics and Center for Nonlinear and Complex Systems, Duke University, Durham, NC 27708, USA

Granular packings subjected to external loading display a spatially heterogeneous distribution of stress along force chains which form a network penetrating the entire system. A general approach is presented for understanding the stress response function in isotropic (disordered packings) and anisotropic (e.g. sheared) granular layers in two dimensions. The formalism accommodates both classical (an-)isotropic elasticity theory and stochastic models for the propagation of force chains (directed force chain networks). Classical, anisotropic materials may show, perhaps surprisingly, two-peak response functions, previously thought to a signature of hyperbolic models. In principle, directed force chain networks can exhibit the two-peak, diffusively spreading response function of hyperbolic models, but all models in a particular class studied here are found to be in the elliptic regime.