Finite size effects during the penetration of objects in a granular medium

Area of Science:

• Physics
• Geotechnical Engineering
• Materials Science

Background:

• Predicting forces during object motion in granular media is crucial for industrial and geotechnical applications.
• Understanding intruder-particle interactions is key to designing effective systems.

Purpose of the Study:

• To experimentally investigate the vertical penetration of intruders into granular media.
• To analyze the average force and fluctuations during motion, particularly for intruder sizes comparable to a few grain sizes.

Main Methods:

• Experimental study of vertical intruder penetration.
• Analysis of average force and force fluctuations.
• Investigation of finite size effects and scaling laws.

Main Results:

• Finite size effects significantly increase mean force and fluctuations as intruder size approaches grain size.
• Scaling laws were identified to characterize the intruder size to particle size ratio effect.
• Conical tips were found to be more efficient for penetration at lower intruder-to-grain size ratios.

Conclusions:

• The ratio of intruder size to particle size critically influences penetration dynamics.
• Conical intruder tips offer a method to reduce penetration resistance, particularly in specific size regimes.