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DY: Fachverband Dynamik und Statistische Physik

DY 21: Granular Matter/Contact Dynamics

DY 21.5: Vortrag

Mittwoch, 28. März 2012, 15:30–15:45, MA 144

A local view on dilatancy onset in sheared granular media — •Annika Döring¹, Jean-François Métayer¹, Mario Scheel², and Matthias Schröter¹ — ¹Max Planck Institute for Dynamics and Self-organization, Göttingen, Germany — ²European Synchrotron Radiation Facility Beamline ID15, Grenoble, France

A recent study on slowly sheared granular media has shown a change in the behaviour of the yield shear stress as a function of packing fraction Φ [1]: for packing fractions below 0.595 the shear stress depends weakly on phi whereas above this value the dependence on Φ is much stronger. It was suggested that this change is the signature of dilatancy.

In order to verify this hypothesis we made tomographies of a slowly sheared granular bed at the ESRF synchrotron in Grenoble.

Using Voronoi tessellation and particle tracking we have been able to access the local variation of the packing fraction and the individual displacement of grains while the bed is sheared. We present these quantities as a function of the initial packing fraction (before the bed is sheared) and test how it is related to the transition shown in [1].

[1] J-F. Métayer, D. Suntrup, C. Radin, H. Swinney, and M. Schröter, EPL 93 (2011) 64003