Da Vinci's friction for granular media.
Assaf Miron1, Rafael Tadmor2, Victor Multanen3
1Civil and Environmental Engineering Department, Faculty of Engineering Sciences, Ben- Gurion University of the Negev, Beer-Sheva, Israel.
Scientific Reports
|January 4, 2025
Summary
This study revives the friction coefficient concept for granular materials, showing kinetic friction depends on fluid and granule shape. Minimal friction is a universal constant, ¼, as identified by da Vinci.
Area of Science:
- Physics
- Materials Science
- Tribology
Background:
- Friction is a key concept in tribology, studied since the 20th century.
- The older friction coefficient concept is being revived for granular materials.
Purpose of the Study:
- To demonstrate that the friction coefficient is a defining parameter for granular materials.
- To establish a predictive model for kinetic friction in granular systems.
- To identify the conditions for minimal friction and its universal constant.
Main Methods:
- Reviving and applying the friction coefficient concept to granular materials.
- Analyzing the influence of lubricating fluids and granule shape on kinetic friction.
- Deriving a friction model without fitting parameters.
Main Results:
- Kinetic friction coefficients are predictable based on fluid properties and granule shape.
- The minimal friction for granular media is a universal constant of ¼.
- Friction increases with system-specific properties.
Conclusions:
- The friction coefficient is a fundamental parameter for granular materials.
- A universal constant for minimal friction in granular systems has been identified.
- This work provides a new framework for understanding and controlling friction in granular media.
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