Stress overshoot, hysteresis and Bauschinger effect in sheared dense colloidal suspensions

TL;DR

This study investigates the nonlinear mechanical response of dense colloidal suspensions under shear, revealing history-dependent behaviors such as stress overshoot, hysteresis, and microstructural anisotropy effects through experiments and simulations.

Contribution

It provides new insights into the history-dependent nonlinear rheology and microstructural evolution of dense colloidal suspensions under shear.

Findings

Stress overshoot occurs when flow starts from rest.

Stress overshoot is absent after flow reversal.

Microstructural anisotropy lags behind stress response.

Abstract

The mechanical non-linear response of dense Brownian suspensions of polymer gel particles is studied experimentally and by means of numerical simulations. It is shown that the response to the application of a constant shear rate depends on the previous history of the suspension. When the flow starts from a suspension at rest, it exhibits an elastic response followed by a stress overshoot and then a plastic flow regime. Conversely, after flow reversal, the stress overshoot does not occur, and the apparent elastic modulus is reduced while numerical simulations reveal that the anisotropy of the local microstructure is delayed relative to the macroscopic stress.