Eur. Phys. J. E (2017) 40: 56
https://doi.org/10.1140/epje/i2017-11543-3

Regular Article

Pressure dependence of the electrical transport in granular materials

¹ Laboratoire de Mécanique des Fluides et Acoustique, Ecole centrale de Lyon, CNRS, Univ. de Lyon, 69134, Ecully, France
² Univ. Paris Diderot, Sorbonne Paris Cité, MSC, CNRS, 75013, Paris, France
³ Laboratoire des Ecoulements Géophysiques et Industriels, Univ. Grenoble Alpes, CNRS, 38058, Grenoble, France

^* e-mail: mathieu.creyssels@ec-lyon.fr

Received: 17 November 2016
Accepted: 14 April 2017
Published online: 11 May 2017

Abstract

We report on systematic measurements of the electrical resistance of one- and three-dimensional (1D and 3D) metallic and oxidized granular materials under uni-axial compression. Whatever the dimension of the packing, the resistance follows a power law versus the pressure (), with an exponent much larger than the ones expected either with elastic or plastic contact between the grains. A simple model based on a statistical description of the micro-contacts between two grains is proposed. It shows that the strong dependence of the resistance on the pressure applied to the granular media is a consequence of large variabilities and heterogeneities present at the contact surface between two grains. Then, the effect of the three-dimensional structure of the packing is investigated using a renormalization process. This allows to reconcile two extreme approaches of a 3D lattice of widely distributed resistances: the effective medium and the percolation theories.