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Slow drag in granular materials under high pressure
Fuping Zhou1, Suresh G Advani, Eric D Wetzel
1Department of Mechanical Engineering and Center for Composite Materials, University of Delaware, Newark, Delaware 19716, USA.
Summary
This study quantifies the drag force on a rod moving through compacted granular materials. Drag force increases with rod length and particle size, and is proportional to compaction pressure and rod diameter.
Area of Science:
- Physics
- Materials Science
- Geotechnical Engineering
Background:
- Understanding granular material behavior under pressure is crucial for engineering applications.
- Quantifying resistance to motion in granular media informs predictive models.
Purpose of the Study:
- To experimentally investigate the drag force experienced by a cylindrical rod moving through a pressurized granular medium.
- To determine the influence of rod dimensions, particle size, and compaction pressure on drag force.
Main Methods:
- Experimental setup involving a confined granular bed compacted under high pressure.
- Pulling a cylindrical rod at a constant, slow rate through the medium to measure drag force.
- Nondimensional analysis to establish relationships between variables.
Main Results:
- Drag force is independent of rod velocity.
- Drag force shows linear proportionality to compaction pressure and rod diameter.
- Drag force increases with rod length and granular particle size.
- Effective granular bed density increases linearly with pressure.
Conclusions:
- The findings provide essential data for developing constitutive models for solid object motion in high-pressure granular media.
- Results are applicable to scenarios like ballistic penetration in soils and ceramic armors.