Analytical Prediction of Hole Diameter in Thin Plates Due to Hypervelocity Impact of Spherical Projectiles

Abstract

A first-principles-based model is presented for calculating the hole diameter resulting from the normal hypervelocity impact of a spherical aluminum projectile on a thin aluminum plate. One-dimensional shock theory is used to predict the creation and attenuation of Hugoniot pressures along the plate surface. Pressures are translated into the plate thickness by calculating intersecting positions of advancing shock fronts and centered-fan rarefaction waves. The radial position at which the shock pressure equals a predetermined value is defined to be the hole diameter. The model was calibrated by determining this critical value for aluminum-an-aluminum impacts using several hundred data points. A residuals analysis indicated some inherent problems with the model. Two empirical factors were added to account for thin plate and two-dimensional shock dissipation effects. The predictions of the adjusted model are shown to compare well with predictions of several empirical hole diameter models.

Debris Cloud Material Characterization for Hypervelocity Impacts of Single- and Multimaterial Projectiles on Thin Target Plates

“…The mass of the projectile material in the debris cloud is known a priori; the mass of the target material in the debris cloud is determined by multiplying the target hole-out area by the target thickness and the target material density. The diameter of the hole created in the target plate by the initial impact can be calculated using anyone of a number of empirical equations for hole diameter in a thin plate due to a high speed impact (see, e.g., Jolly, 1993).…”