Mechanics of high speed impact at normal incidence between plasticine long rods and plates

A brief literature review of long rod impact is given. Experimental results and observations on the penetration and perforation of plasticine targets of finite thickness (25 and 50 mm) impinged upon normally by long rods of plasticine of various length-to-diameter ratios (2-12) are presented and discussed. An account of the range of modes of deformation as it pertains to long rods and targets of identical materials is given, i.e. mushrooming of the projectile leading-end, partial penetration and embedment of the projectile in the target, gross target penetration by the projectile, and penetration followed by perforation. The difference in penetration behaviour as between long and short rods is discussed. Plasticine has been used for both the target and projectile materials in order to simulate hypervelocity impact conditions for deformable long rod projectiles on deformable target plates. This permits the use of equipment based on an industrial stud driver which is substantially cheaper than the equipment (e.g. a light gas gun) required to achieve the range of speeds necessary for hypervelocity conditions with real ballistics-related metals and alloys. Projectile-target interactions and damage observed in the present tests compare well with those reported in similar investigations using metallic projectiles and targets. The attraction of performing ballistics experiments with plasticine models outweighs such inherent limitations as the inability to model the extreme conditions of temperature and strain-hardening in real materials, because testing is cheap and easily performed in a laboratory.