Impact Study on Composite Targets by a Nylon Projectile

Abstract

In the present paper, impact study of nylon projectile on composite targets using a water-jet disruptor was addressed with damage mechanism. The three different composite targets such as teak, ply and pine woods were used in the experiment. The strength of wood and the damage under impact load is very crucial. The failure under load is very intricate as it is made up of natural composite. The composite target damage mechanism depends on characterisation and impact velocity of projectile. Simultaneously stresses and strains are generated which makes it responsible to cause the damage. Disruptor using water-jet plays a very crucial role in neutralising Improvised Explosive Devices (IEDs) with the minimum risk. These devices are designed to generate a high velocity water-jet using an electrically initiated gas generator cartridge. This helps in separating the critical components of IED’s and avoiding them from operating as anticipated. The damage caused by a waterjet disruptor is not quantified in assessing the performance. However, at present no technique was available to evaluate the performance. The terminal ballistics tests at the target end are found appropriate for solid projectiles, such as penetration of bullet into target plates or impact of fragments. These terminal effects are the good indicators considering the destruction. The available alternative measurement techniques are cost effective that forms a basis for future common test protocols. The authors suggested that craters made by a nylon projectile using the disruptor provide a quantitative measure. This should be considered as a potential for upcoming standard test for evaluating the performance. The impact caused by a nylon projectile is dependent on projectile kinetic energy and the dissemination of stress wave in the surrounding zone. The energy dissipated by a nylon projectile gets absorbed by the targets through a certain mechanisms. Ballistic velocities for various targets are also worked out. Pinewood has less ballistic velocity limit as compared to other two targets. Study and methods for the disruptor performance on various composite targets (plywood, teak wood and pinewood with 15 mm thickness) at 0.5 and 1m stand-off distances are evaluated. This compares with the respective common target tests. From the experiments, it is concluded that a nylon projectile has potential to penetrate through composite targets.