Study on a System with a Neutral Barrier for High Explosives and a Zirconium-Based Solid Incendiary

Abstract

In the aim of defeating targets protected by fortification, it is necessary to develop systems that are able to create a leak in the fortification and destroy targets inside the fortification. A boat-tailed hemispherical high explosive charge was designed to create the leak and an incendiary charge was prepared to burn the targets inside the fortification. A metallic neutral barrier was used to attenuate the back pressure generated by the front end hemispherical high explosive charge. In order to reduce the back blast, a boat-tailed hemispherical charge with the composition cyclotrimethylene trinitramine and trinitrotoluene (RDX/TNT 60/40) was prepared. The blast pressure obtained from unconfined boat-tailed high explosive charges using a linear pressure gauge brought to light that the pressure at the front end had a value of 2.3 MPa at 100 cm; and a value of 0.4 MPa at 75 cm distance at the rear end. A hemispherical boat tailed shaped charge with a mild steel liner of 1 mm thickness and 40 mm curvature radius was prepared. The incendiary composition comprised of finely divided metal powder dispersed in a polymer matrix consisting of 77 % zirconium and 20 % ester gum resin with 3 % polymeric binder (SBR, PIB). The incendiary composition was prepared and pelletized. Experiments for the design of the neutral barrier were conducted with the boat-tailed hemispherical charge. A mild steel plate of 7.5 mm thickness was selected as neutral barrier. Static evaluation of the system against a hard target was carried out. It created a hole of 190 mm diameter in a reinforced concrete cement (RCC) target of 100 mm thickness. A neutral barrier of 7.5 mm thickness attenuates the back blast of the hemispherical boat-tailed charge. Burning incendiary cinders were passed through this hole and dispersed at approx. 5 m distance. These cinders burnt for > 3 min with a temperature output of 1873 K.