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Slow flows of yield stress fluids: Complex spatiotemporal behavior within a simple elastoplastic model
Guillemette Picard1, Armand Ajdari, François Lequeux
1Laboratoire P.C.T., UMR CNRS 7083, ESPCI, 10 rue Vauquelin, 75005 Paris, France.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|February 9, 2005
Summary
A new model explains the flow of dense disordered materials using plastic events and stress release. Collective bursts in fragile zones drive flow at low rates, with localization near walls in confined spaces.
Area of Science:
- Soft Matter Physics
- Rheology
- Materials Science
Background:
- Dense disordered materials exhibit complex flow behaviors.
- Understanding the underlying mechanisms of plastic deformation is crucial.
Purpose of the Study:
- To propose a minimal athermal model for dense disordered material flow.
- To explain the complex rheological behavior observed in experiments.
Main Methods:
- Developed a model incorporating local plastic events above a yield stress.
- Included nonlocal elastic stress release from these events.
Main Results:
- The model reproduces complex spatiotemporal rheological behavior.
- Macroscopic flow at low shear rates arises from collective bursts in fragile zones.
- Correlation length diverges algebraically at low shear rates.
- Flow localization occurs near walls in confined geometries.
Conclusions:
- The proposed model provides a framework for understanding dense disordered material flow.
- Collective plastic events and stress release are key to material behavior.
- The model aligns with experimental observations and offers insights into flow localization.