ANALYTICAL PREDICTION OF HOLE DIAMETER IN THIN PLATES DUE TO HYPERVELOCITY IMPACT OF SPHERICAL PROJECTILES

A first-principles-based model is presented for calculating the hole d iameter resulting from the normal hypervelocity impact of a spherical aluminum projectile on a thin aluminum plate. One-dimensional shock th eory is used to predict the creation and attenuation of Hugoniot press ures along the plate surface. Pressures are translated into the plate thickness by calculating intersecting positions of advancing shock fro nts and centered-fan rarefaction waves. The radial position at which t he shock pressure equals a predetermined value is defined to be the ho le diameter The model was calibrated by determining this critical valu e for aluminum-on-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-dim ensional shock dissipation effects. The predictions of the adjusted mo del are shown to compare well with predictions of several empirical ho le diameter models.