Spatial repartition of local plastic processes in different creep regimes in a granular material
Abstract
Granular packings under constant shear stress display below the Coulomb limit, a logarithmic creep dynamics. However the addition of small stress modulations induces a linear creep regime characterized by an effective viscous response. Using Diffusing Wave Spectroscopy, we investigate the relation between creep and local plastic events spatial distribution ("hot-spots") contributing to the plastic yield. The study is done in the two regimes, i.e. with and without mechanical activation. The hot-spot dynamics is related to the material effective fluidity. We show that far from the threshold, a local visco-elastic rheology coupled to an ageing of the fluidity parameter, is able to render the essential spatio-temporal features of the observed creep dynamics.
Keywords
Cite
@article{arxiv.1601.05671,
title = {Spatial repartition of local plastic processes in different creep regimes in a granular material},
author = {A Pons and T Darnige and Jérôme Crassous and E Clément and Axelle Amon},
journal= {arXiv preprint arXiv:1601.05671},
year = {2016}
}