BALLISTIC TRADE-OFFS FOR DEPLETED URANIUM REPLACEMENT IN A KINETIC ENERGY PENETRATOR

Abstract

Depleted uranium (DU) alloys are often employed in kinetic energy penetrators as they show superior terminal ballistic performance over other materials, such as tungsten heavy alloys (WHA). This performance gap is generally attributed to differences in deformation behavior, such as adiabatic shearing in DU alloys. However, due to several factors associated with the use of DU, there is a need to seek a replacement material. The objective of this paper is to identify and model the trade-offs available or required in internal and external ballistics as a function of density of a WHA material such that it would match the modelled terminal performance a DU alloy penetrator. The performance is modelled using the Baer-Frankle lumped parameter model for the internal ballistics, the flat-fire trajectory approximation for the external ballistics and the Walker-Anderson penetration model for the terminal ballistics of a tungsten-like material. The conversion of the deformation behaviour of WHA to a DUlike failure mode is developed from the data of Magness & Farand based on relative crater ratios in the impact velocity range of 800 to 1000 m/s. Modifications, such as the penetrator’s length and a change in propellant, are suggested to define the lower boundaries of density. However, the change to a more energetic propellant would increase barrel erosion rates. With a WHA alloy failing by adiabatic shearing, the minimum required density to match the DU penetrator could be as low as 14.5 g/cm3 but with implications for round stability and an increase in barrel wear rate.