Eur. Phys. J. E (2014) 37: 43
https://doi.org/10.1140/epje/i2014-14043-0

Regular Article

Rheological properties vs. local dynamics in model disordered materials at low temperature

¹ Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, F-69622, Villeurbanne Cedex, France
² MATEIS CNRS UMR5510, INSA-Lyon, F-69621, Villeurbanne Cedex, France

^* e-mail: Anne.Tanguy@univ-lyon1.fr

Received: 21 November 2013
Revised: 29 March 2014
Accepted: 11 April 2014
Published online: 27 May 2014

Abstract

We study the rheological response at low temperature of a sheared model disordered material as a function of the bond rigidity. We find that the flow curves follow a Herschel-Bulkley law, whatever is the bond rigidity, with an exponent close to 0.5. Interestingly, the apparent viscosity can be related to a single relevant time scale t _rel, suggesting a strong connection between the local dynamics and the global mechanical behaviour. We propose a model based on the competition between the nucleation and the avalanche-like propagation of spatial strain heterogeneities. This model can explain the Herschel-Bulkley exponent on the basis of the size dependence of the heterogeneities on the shear rate.