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DY: Fachverband Dynamik und Statistische Physik

DY 21: Granular Matter / Contact Dynamics

DY 21.12: Vortrag

Mittwoch, 13. März 2013, 18:00–18:15, H47

Compaction of Cohesive Granular Matter — •Sebastian Seemann, Alexander Weuster, Lothar Brendel, and Dietrich E. Wolf — Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg, Germany

For granular media with grain sizes in and below the µm-range, interparticular cohesion forces have a major influence on the macroscopic behavior of the medium. Especially, the porosity of a granular packing increases with increasing cohesion force. We use molecular dynamics to study the response of cohesive granular matter to uniaxial compression. With increasing pressure, remaining pores within the packing are closed and the porosity therefore decreases. Previous results [1,2] have shown that this dependency (the compaction law) is described by a power law. However, a discrepancy regarding the exponent still exists. Our approach to clear up this discrepancy is twofold. On one hand, we study the response of a ballistic aggregate to a fast, pressure-driven compaction and elucidate the effects of particle elasticity. In this case the behavior is more complex. The role of elastic contributions in the case of shock-compaction is discussed. On the other hand, we use a velocity-driven wall to compress the packing in a quasistatic manner. We will show that elastic effects cease to play a role and we present results for the compaction law and its exponent.

[1] D. Kadau. Porosität in kohäsiven Pulvern und Nano-Pulvern, Dissertation, Universität Duisburg-Essen (2004)

[2] F. A. Gilabert, J.-N. Roux, and A. Castellanos, Phys. Rev. E 78, 031305 (2008)