Onset of shear flow in confined soft glasses

by Prof. Chaudhuri Pinaki (University of Dusseldorf)

Wednesday 20 Nov 2013, 11:00 → 13:00 Europe/Rome

Sala Touschek (Dipartimento di Fisica - Ed. G. Marconi)

A defining mechanical property of amorphous materials is the existence of a yield stress; in the case of soft materials, flow occurs only when the applied stress exceeds a threshold value. Understanding the mechanisms of yielding and subsequent flow is important for a variety of rheological applications. In this context, it has been recently proposed that spatially correlated plastic events drive the flow, implying that spatial confinement would impact the nature of dynamical properties. We explore these issues by using numerical simulations to study the response of a confined quiescent glass to different stress fields, viz. Couette (spatially homogeneous) and Poiseuille (spatially inhomogeneous). We demonstrate how the dynamics at the local scale is linked to observed macroscopic rheology. Further, using complementary experimental studies, we try to build up the scenario! for the onset of flow in such materials.