Projectile-shape dependence of impact craters in loose granular media

TL;DR

This study investigates how projectile shape and physical parameters affect impact crater depth in granular media, revealing scaling laws for deep impacts and shape effects for shallow impacts.

Contribution

It introduces a comprehensive analysis of projectile shape and size effects on impact penetration in granular media, deriving new scaling laws for deep impacts.

Findings

Deep impact depth scales with drop distance, cylinder length, and diameter.

Sharper projectiles penetrate deeper in shallow impacts.

Data collapse onto a unified scaling law for deep impacts.

Abstract

We report on the penetration of cylindrical projectiles dropped from rest into a dry, noncohesive granular medium. The cylinder length, diameter, density, and tip shape are all explicitly varied. For deep penetrations, as compared to the cylinder diameter, the data collapse onto a single scaling law that varies as the 1/3 power of the total drop distance, the 1/2 power of cylinder length, and the 1/6 power of cylinder diameter. For shallow penetrations, the projectile shape plays a crucial role with sharper objects penetrating deeper.