Design and Development of Non-initiating Precursor for Tandem Warhead Against Explosive Reactive Armour

Abstract

Defeating or neutralizing explosive reactive armour (ERA) fixed onto a tank or any other vehicle is of prime importance. Accordingly, an explosively formed penetrator (EFP), which can perforate the ERA without detonation, is an effective technique for the same purpose. Thus, this EFP has been designed for fitting in the precursor of a tandem warhead known as the non-initiating precursor (NIP). Comp-B was taken as the main charge for the NIP in 60:40 ratio of TNT to RDX. The second-generation ERA Kontakt-5 was chosen for the ibid purpose, which has a nomenclature of 15-35-20. The numbers represent the thickness of the rolled homogenous armour (RHA), explosive and RHA in millimetres respectively. Four lighter materials, namely aluminium, epoxy resin, perspex and Teflon were selected for the liner of EFP. The non-initiating precursor could defeat the ERA if a hole is made in its front plate without detonating the explosive. The main warhead of the tandem completes the rest of the task. The front plate of ERA, which has a thickness of 15 mm, was chosen for the perforation by the EFP at 90 and 30 degrees with the horizontal. The effective thickness of the front plate increases from 15 to 30 mm when the angle is changed from 90 to 30 degrees. Therefore, two distinct liners of each material were designed for the two attack angles. In total, eight liners were successfully designed using Autodyn for this purpose. Four liners were designed for the 90 degree or normal hit and four for the 30 degree or oblique hit. The successful designs of the liners obtained from Autodyn simulations were cross-checked with the LS-Dyna software and were found in agreement. In the first stage of experiments, the designed liners were tested against the front plate of ERA and in the second stage against the fully integrated ERA consisting of the front plate, explosive cassette, back plate and the casing altogether. Two experiments were performed in the first stage with liners made of aluminium and perspex. The jet shapes were captured during the flight before hitting the target with the flash radiography technique. Shapes of the jet .obtained in the experiments by radiography and from simulations carried out by Autodyn and LS Dyna were in complete agreement. Similarly, the shapes of the bored holes observed on the plates after the experiment and those obtained from the two simulation software were also consistent; however, the diameters of the holes obtained in the experiments were significant than the simulations. In the second stage, eight experiments were performed to study the interaction of EFP/NIP with the fully integrated explosive reactive armour. The detonation of ERA cassette was witnessed in three out of eight experiments, whereas NIP did not detonate the ERA in the rest of the experiments. In total, seven out of ten experiments gave the desired results having a 70% success rate. The experiments performed on the interaction of NIP and ERA indicated that NIP is not a universal solution and the performance of NIP highly depends upon the angle of attack and the type of ERA. The upshot of this work is that NIP is a promising technique to defeat a specific ERA without detonation vis-a-vis the ibid limitations.