Effect of projectile shape and interior structure on crater size in strength regime

TL;DR

This study investigates how projectile shape and interior structure influence crater size in the strength regime, finding that crater dimensions can be reliably scaled using conventional laws regardless of projectile differences.

Contribution

It demonstrates that crater size scaling laws are applicable across different projectile shapes and interior structures in the strength regime, supported by experiments and simulations.

Findings

Crater dimensions are similar across projectile shapes and structures.

Distribution of peak pressure and particle velocity are unaffected by projectile differences.

Crater size can be scaled using bulk density in the strength regime.

Abstract

Experiments on crater formation in the strength regime were conducted using projectiles of various shapes with an aspect ratio of ~1, including both solid and hollow interiors. The surface diameter, inner (pit) diameter, and depth of the craters on basalt and porous gypsum targets were measured. Using the bulk density of the projectile, the surface diameter and depth for basalt and the pit diameter and depth for porous gypsum were scaled using the pi-scaling law for crater formation in the strength regime. The numerical code iSALE was used to simulate the impact of projectiles of various shapes and interior structure with similar bulk densities. Results show that the distributions of the maximum (peak) pressure experienced and particle velocity in the targets were similar regardless of projectile shape and interior structure, implying that the dimensions of the final craters were almost identical. This is consistent with the experimental results. Thus, we conclude that the size of the craters formed by the impact of projectiles with different shape and interior structure can be scaled using a conventional scaling law in the strength regime, using bulk density as projectile density.