Criticality and avalanches at the yielding transition of amorphous solids under deformation

by Dr Ezequiel Ferrero (Dipartimento di Fisica - Università degli Studi di Milano)

Thursday 20 Apr 2017, 14:30 → 15:30 Europe/Rome

0M03 (Dipartimento di Fisica Ettore Pancini)

Materials as diverse as foams, emulsions, colloidal glasses and dense granular suspensions display asimilar behavior when submitted to an external deformation or stress. They respond elastically -as a solid- over small perturbations, but they deform plastically and flow if a threshold is overcome. This phenomenon is known as the yielding transition and exhibits many properties common to dynamical phase transitions, described by analogies with equilibrium critical phenomena. A theoretical understanding of yielding can be practically relevant at many scales, ranging from the plasticity of metallic glasses to landslides and earthquakes. In this talk, I will describe the yielding phenomenon from a statistical physics point of view. To that end, I will first introduce a coarse-grained approach to amorphous solids, the so-called elastoplastic models. Then, I will focus on the statistics of avalanches produced by a characteristic stickslip behavior close to the yielding threshold. On the way, the current understanding of yielding from mean-field descriptions and comparison with the depinning transition of an elastic line, will be briefly reviewed.