How Glasses Relax and Go With the Flow

All solids flow at high enough applied stress and melt at high enough temperature.  Crystalline solids flow and  premelt via localized particle rearrangements that occur preferentially at structural defects known as dislocations.  The population of dislocations therefore controls both how crystalline solids flow and how they melt.  In glasses, there is considerable evidence that localized particle rearrangements induced by stress or temperature occur at localized flow defects but attempts to identify them directly from structure alone have failed.  We have introduced a novel application of machine learning data mining methods to diagnose flow defects, or “soft” particles from their local structural environments.  We use machine learning to define a particle-based quantity, “softness,” that is highly correlated with the propensity of the particle to rearrange. I will focus on quasistatically-sheared athermal jammed packings and untangle the interplay of softness, rearrangements and elasticity during avalanches to develop a coarse-grained “structuro-elasto-plasticity” model.

Part of the NSCS webinar series

https://softmatterisrael.wixsite.com/nscs