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Edwards thermodynamic framework controls density segregation in cyclically sheared granular materials
Haiyang Lu1, Houfei Yuan1, Shuyang Zhang1
1Shanghai Jiao Tong University, School of Physics and Astronomy, Shanghai 200240, China.
Physical Review. E
|July 24, 2026
Summary
Granular segregation, driven by density differences, can be explained by a thermodynamic framework. This model uses a segregation temperature to quantify particle mixing and gravitational forces.
Area of Science:
- Physics
- Materials Science
- Statistical Mechanics
Background:
- Granular segregation is common in nature and industry.
- Existing models are often qualitative and lack a statistical mechanics basis.
Purpose of the Study:
- To develop a unified theoretical framework for granular segregation.
- To experimentally investigate segregation using statistical mechanics.
Main Methods:
- X-ray tomography to observe particle behavior.
- Quasistatic cyclic shear applied to particle mixtures.
- Analysis of particle height distributions and structural relaxation.
Main Results:
- Steady-state height distributions are explained by minimizing effective free energy.
- A segregation temperature quantifies the balance between entropy and potential energy.
- This temperature aligns with Edwards' compactivity.
Conclusions:
- Granular segregation under quasistatic conditions can be fundamentally explained by thermodynamics.
- The Edwards statistical ensemble provides a framework for understanding segregation.
- This work offers a quantitative, physics-based approach to granular segregation.
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