Depth dependence of vertical plunging force in granular medium
Zheng Peng1, Xiantao Xu, Kunquan Lu
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Summary
The vertical plunging force in granular media shows a concave-to-convex transition as objects are pushed deeper. This force transition is linked to the volume of granular material filling the space above the intruder.
Area of Science:
- Physics
- Materials Science
- Granular Mechanics
Background:
- Understanding the forces acting on objects penetrating granular materials is crucial for various applications, from geotechnical engineering to robotics.
- Previous models often assumed simple force-depth relationships, potentially overlooking complex behaviors.
Purpose of the Study:
- To experimentally investigate the depth dependence of the vertical plunging force exerted by objects intruding into a granular medium.
- To identify and characterize the transition in force behavior during object immersion.
Main Methods:
- Experimental measurement of slow-pushing forces for objects of varying size and shape vertically penetrating a granular bed.
- Analysis of force curves to identify transitions and inflection points.
Main Results:
- Observed a concave-to-convex transition in the force-depth curves for fully immersed intruders.
- The transition from supralinear to sublinear force dependence was identified.
- The inflection point's force was found to be proportional to the intruder's volume, occurring at approximately twice the intruder's diameter depth.
- No inflection point was observed for partially immersed long cylinders.
Conclusions:
- The observed force inflection is attributed to the filling of granular material above the intruder, not sidewall support.
- This finding refines our understanding of granular resistance and intrusion mechanics.
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