Predicting metallic armour performance when impacted by fragment-simulating projectiles – model review and assessment

Abstract

Metallic targets impacted by blunt-nosed, fragment-simulating projectiles typically fail via shear plugging. A number of models exist in open literature to predict the onset of this failure mode, which can be used to determine the ballistic limit velocity, VBL, for a particular combination of projectile and target plate. A set of nine existing penetration models for blunt projectiles were identified and reviewed for their ability to predict the plugging-mode ballistic limit velocity of monolithic titanium alloy, aluminium alloy, and steel alloy plates impacted by blunt-nosed, fragment simulating projectiles. A database of more than 650 experimental ballistic limit measurements was used to evaluate the performance of the predictive models, covering a wide range of ordnance and sub-ordnance velocities, normal and oblique impact angles, and target plate thicknesses. The range of experimental data typically exceeded that for which the applied models were derived or previously validated. Nonetheless, it was found that all nine models could predict the experimental ballistic limit to within +/- 50% of the experimental measurement for more than 50% of the ballistic tests considered.