Penetrating a granular medium by successive impacts.

Area of Science:

• Physics
• Mechanical Engineering
• Materials Science

Background:

• Understanding object penetration into granular materials is crucial for various engineering applications.
• Previous studies have explored impact dynamics, but a comprehensive model for successive impacts is lacking.

Purpose of the Study:

• To investigate the dynamics of a vertical cylinder penetrating dry granular media under successive impacts.
• To develop a predictive model for penetration depth based on impact parameters and granular properties.

Main Methods:

• Experimental analysis of cylinder penetration depth over multiple impacts.
• Development of a theoretical model incorporating quasistatic and inertial granular forces.
• Investigation of the effects of lateral confinement.

Main Results:

• Penetration depth initially increases linearly with impact number, then follows a power law (zN ∝ N^1/3).
• Depth is positively correlated with impact energy and negatively with cylinder diameter and granular density.
• Two distinct intrusion regimes were identified, enabling data rescaling onto a master curve.
• Lateral confinement was shown to alter the impact number dependence of penetration depth.

Conclusions:

• The developed model successfully rationalizes the observed penetration dynamics and parameter dependencies.
• The study identifies key factors governing cylinder penetration in granular media, including impact energy, geometry, material properties, and confinement.
• Findings provide insights into the complex interplay between impactor and granular medium behavior.