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
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.
Key words: Flowing Matter: Granular Matter
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2017