Rheological properties vs Local Dynamics in model disordered materials at Low Temperature

2014/03/31 by Fusco, C., Albaret, T., Tanguy, A.
#FOS: Physical sciences #Soft Condensed Matter (cond-mat.soft)

paper · doi:10.48550/arxiv.1403.7950

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.

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