Shear zones in granular materials: optimization in a self-organized random potential
1Department of Chemical Information Technology, Budapest University of Technology and Economics, H-1111 Budapest, Hungary.
Summary
A new model explains wide shear zones in granular materials during modified Couette cell experiments. This approach, based on minimizing dissipation, accurately matches experimental data and offers predictive capabilities for granular flow.
Area of Science:
- Physics
- Materials Science
- Rheology
Background:
- Granular materials exhibit complex flow behaviors.
- Modified Couette cell experiments reveal wide shear zones.
- Existing models may not fully capture these phenomena.
Purpose of the Study:
- To introduce a novel model for describing wide shear zones in granular materials.
- To generalize a previous variational principle approach.
- To provide a theoretical framework for understanding granular shear band formation.
Main Methods:
- Developed a generalized variational principle model.
- Identified instantaneous shear bands by minimizing dissipation in a biased random potential.
- Calculated apparent shear zones as the ensemble average of instantaneous bands.
- Performed numerical simulations of the proposed model.
Main Results:
- The model successfully describes wide shear zones observed in experiments.
- Numerical simulations show excellent agreement with experimental data.
- The model yields measurable predictions for granular material behavior.
Conclusions:
- The developed model provides a robust explanation for wide shear zones in granular flows.
- The variational approach effectively captures the interplay of velocity, pressure, and dissipation.
- The model's predictive power validates its utility in granular rheology.
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