Kirsten Martens


Université Grenoble Alpes

140 Av. de la physique BP 87

F-38402 Saint Martin d'Hères


Phone: +33 4 76 51 47 41

Fax: +33 4 76 51 45 44


Main collaborators

Lydéric Bocquet (ENS, Paris)

Jean-Louis Barrat (LIPhy, Grenoble)

Solid amorphous materials, under the application of sufficiently large stresses, undergo plastic deformation and flow. Experimental results indicate that the diffusion of tracer particles, e.g. in sheared foam systems and in colloidal glasses, is shear rate dependent. Further observations concern the strong non-local effects in the mechanical response even in quiescent regions far away from the flowing material, and the need for a non local description to account for flow behavior in confined geometry.
At low strain rates the stress dynamics are governed by cooperative regions of plastic events. We showed that there is a direct link between the self-diffusion coefficient and the size of cooperative regions at low strain rates. Both depend strongly on rate and on system size. A measure of the mean square displacement of passive tracers in deformed amorphous media can thus give information about microscopic rheology, such as the geometry of the cooperative regions and their scaling with shear rate and system size.

Connecting diffusion and dynamical heterogeneities in actively deformed amorphous systems

Is there a connection between dynamical heterogeneities

and the self diffusion of tracer particles

in sheared amorphous media?


Typical accumulated activity of plastic events and typical non-affine displacement field both for small strain rates.

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