Cratering experiments in sands and a trial for general scaling law

Abstract

We report results of vertical impacts of aluminum projectiles into quartz sand. The impacts were performed at velocities of 35 to 830 m/sec with a single stage powder gun. Morphology of craters formed in loose sands is generally conical, whereas morphology of craters formed in self‐compacted sands varies from a flat‐floor type to a double ring type, with increasing impact velocity. The present data together with previous experimental data and Dienes and Walsh's ‘late‐stage equivalence’ indicate that crater diameter is expressed by a function of the ‘late‐stage effective energy’ but not of the impact kinetic energy. The diameter of a crater formed in a noncohesive sand was found to be proportional to one‐fourth the power of the late‐stage effective energy. For a general impact cratering in a target with a finite strength, the diameter, D, versus impact velocity, v, relation is written as follows: urn:x-wiley:01480227:media:jgrb4659:jgrb4659-math-0001 where v* and D* are normalizing values of the impact velocity and diameter, and K is a constant related to target and projectile properties. The relation suggests that there are four regimes in crater diameter versus the kinetic energy relation.