Giant fluctuations in the flow of fluidised soft glassy materials: an elasto-plastic modelling approach

In this work we study the rheological features of yield stress materials that exhibit non-homogeneous steady flows and that are subjected to an additional mechanical noise. Using a mesoscale elasto-plastic model accounting for a viscosity bifurcation in the flow response to an external shear stress,...

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Bibliographic Details
Published in:arXiv.org 2019-11
Main Authors: Magali Le Goff, Bertin, Eric, Martens, Kirsten
Format: Article
Language:English
Subjects:
Bifurcations
Noise
Noise intensity
Phase transitions
Rheological properties
Rheology
Shear rate
Shear stress
Steady flow
Variation
Yield stress
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Summary:In this work we study the rheological features of yield stress materials that exhibit non-homogeneous steady flows and that are subjected to an additional mechanical noise. Using a mesoscale elasto-plastic model accounting for a viscosity bifurcation in the flow response to an external shear stress, we find that additional sources of noise can lead to a fluidisation effect. As we increase the noise intensity we evidence a transition from a non-monotonic to a monotonic rheology, associated with giant fluctuations of the macroscopic shear rate and long-time correlated dynamics. Although distinct noise models can lead to different rheological behaviours in the low stress regime, we show that the noise-induced transition from shear-localised to homogeneous flow at higher stresses appears very generic. The observed features in the dynamics can be interpreted as a result of an out-of-equilibrium phase transition, for which we estimate the critical exponents that appear to be independent of the specific choice of the noise implementation for the microscopic dynamics.
ISSN:2331-8422