Origin of two distinct stress relaxation regimes in shear jammed dense suspensions

Abstract

Many dense particulate suspensions show a stress induced transformation from a liquid-like state to a solid-like shear jammed (SJ) state. However, the underlying particle-scale dynamics leading to such striking, reversible transition of the bulk remains unknown. Here, we study transient stress relaxation behaviour of SJ states formed by a well-characterized dense suspension under a step strain perturbation. We observe a strongly non-exponential relaxation that develops a sharp discontinuous stress drop at short time for high enough peak-stress values. High resolution boundary imaging and normal stress measurements confirm that such stress discontinuity originates from the localized plastic events, whereas, system spanning dilation controls the slower relaxation process. We also find an intriguing correlation between the nature of transient relaxation and the steady state shear jamming phase diagram obtained from the Wyart-Cates Model.

S.I. included. S.I. movies can be downloaded from https://drive.google.com/drive/folders/10cVxgeY5fl7YKKy32D1XaaTsuFHYLrqU?usp=sharing

References in corpus (3)

• Three-dimensional imaging of colloidal glasses under steady shear
• Growing length and time scales in a suspension of athermal particles
• Competing Time Scales Lead to Oscillations in Shear-Thickening Suspensions

Cited by in corpus (4)

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