Effects of particle angularity on granular self-organization.
Dominik Krengel1, Haoran Jiang2, Takashi Matsushima3
1Tokyo University of Marine Science and Technology, Department of Marine Resources and Energy, 4-5-7, Konan, Minato 108-8477, Tokyo, Japan.
Physical Review. E
|December 23, 2025
Summary
Particle angularity does not affect self-organization in 2D systems, but increasing angularity makes stress distribution sensitive to friction. This impacts understanding of granular materials and cell mechanics.
Area of Science:
- Physics
- Materials Science
- Computational Modeling
Background:
- Two-dimensional polydisperse disk systems exhibit coordinated self-organization of cell stresses and shapes.
- Distributions often collapse onto a master form across various parameters like size, friction, and order.
- The influence of particle shape, specifically angularity, on these self-organization phenomena requires further investigation.
Purpose of the Study:
- To investigate the impact of particle angularity on the self-organization indicators in two-dimensional granular systems.
- To systematically vary the angularity of particles (regular N-gons) and assess its effect on stress-orientation correlations and stress ratio distributions.
- To determine if the observed self-organization phenomena are robust across different particle shapes and friction coefficients.
Main Methods:
- Utilized computational simulations of bidisperse systems composed of regular N-polygons.
- Systematically varied the number of sides (N) of the polygons to represent increasing angularity.
- Analyzed local cell stresses, cell orientations, and conditional distributions of scaled cell stress ratios.
Main Results:
- The strong correlation between local cell stresses and orientations is independent of particle angularity and friction coefficient.
- Conditional distributions of scaled cell stress ratios collapse onto a master Weibull form for all particle orders (k), irrespective of angularity and friction.
- Increasing particle angularity renders the collapses of conditional distributions sensitive to variations in the friction coefficient.
Conclusions:
- The fundamental self-organization of stress and shape in 2D granular systems, characterized by master distribution collapses, is largely independent of particle angularity and friction.
- However, the sensitivity of these distribution collapses to friction increases with particle angularity, suggesting a more complex interplay at higher angularity.
- Findings contribute to understanding the mechanics of granular materials and soft matter systems where particle shape plays a crucial role.
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