Yielding under the microscope: a multi-scale perspective on brittle and ductile behaviors in oscillatory shear

Abstract

We study the yielding transition in soft jammed materials under oscillatory shear, employing a novel methodology that combines rheological measurements with detailed dynamical observations. This method provides a comprehensive view of the intricate interactions between macroscopic mechanical behavior, mesoscopic deformation patterns, and microscopic dynamics during yielding. Our findings reveal two distinct yielding behaviors: at one end, a smooth, uniform transition, characterized by homogeneous strain fields, and Fickian, Gaussian microscopic dynamics; at the other, a sharp transition defined by pronounced shear banding, with the dynamics within shear bands being governed exclusively by the local strain, and exhibiting non-Gaussian, cooperative nature. The viscoplastic fragility emerges as a key macroscopic predictor of these intricate behaviors across micro- and meso-scales, providing a new perspective to understand and quantify ductile and brittle yielding in soft materials.

Roberto Cerbino

Professor of Experimental Soft Matter Physics

My research interests include Soft matter physics, living matter, cell biophysics and quantitative microscopy.