Fluid Mechanics and Acoustics Laboratory - UMR 5509

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Home > Teams > Turbulence & Instabilities > Publications T&I et posters doctorants > Former five-year period > Publications T&I 2017

Article in Eur. Phys. J. E (2017)

Pressure dependence of the electrical transport in granular materials

Mathieu Creyssels, Claude Laroche, Éric Falcon, Bernard Castaing

Pressure dependence of the electrical transport in granular materials

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 ($R\propto P^{−\alpha}$), with an exponent $\alpha$ 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.

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