Towards minimal models for realistic granular materials: Tomographic analysis of bidispersed assemblies of ellipsoids

¹ Institut für theoretische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg Erlangen, Germany
² Centre for Plasmas and Fluids, Research School of Physics and Engineering, Australian National University, Canberra ACT 2601, Australia
³ School of Engineering and Information Technology, Murdoch University, Murdoch WA 6150, Australia
⁴ Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University, Canberra ACT 2601, Australia

^* e-mail: fabian.schaller@fau.de
^** e-mail: g.schroeder-turk@murdoch.edu.au
^*** e-mail: mohammad.saadatfar@anu.edu.au

Published online: 30 June 2017

Abstract

In this paper, we report experimental results on granular compaction in a model system made of mono- and bidisperse ellipsoidal packings as well as sand packings with grain size polydispersity. The packings are subject to vertical tapping of varying duration (number of taps) and their internal three-dimensional structure is obtained using x-ray computed tomography. Particles positions and orientations are reconstructed and the global packing densities are computed. The analysis of the vertical and horizontal local packing fraction profiles reveal a homogeneous densification in the ellipsoidal packings, however, sand packings exhibit radial density gradient, possibly linked to the onset of convection.