Effect of Liner Cone Angle, Liner Thickness and Wave Shaper in Large Caliber Shaped Charge Warheads

Abstract

Shaped charge warheads are being utilized in defence applications against a wide variety of targets provided by armour, RCC and soil cover. Shaped charge warhead focus the explosive energy by the use of a cavity lined with metal normally called a liner. The concentration of energy along the axis of the warhead acts as force multiplier and hence lighter warheads are possible for deeper penetration. Performance of the shaped charge warhead is function of jet tip velocity, jet length and break up time (BUT). These performance parameters are greatly influenced by liner geometry, liner thickness and liner cone angle and selection of explosive. In this paper, simulations using AUTODYN numerical hydrocode were carried out to study the effect of liner geometry (Tulip vs conical), liner cone angle (50,60,70,80) and liner thickness(4mm,6mm,8mm,10mm and 12mm) on large caliber shaped charge warheads. Numerical simulations were also done to study the effect of wave shaper in shaped charge warhead. A shaped charge warhead of dia.340mm has been designed by using AUTODYN numerical hydrocode. OFE Copper (ASTM B152 C10100) is used as liner material. A wave shaper of dia.210mm and nylon material was used in shaped charge warhead. An Eulerian approach was used for the liner, casing, wave shaper and explosive parts. A single point initiation in the centre of the rear end of warhead was chosen. The numerical simulation results showed that the jettip velocity decreases in between 15-20% of liner position with increasing the cone angle when the other parameters are the same. For the cone angle 60, jet tip-velocity decreases as liner thickness is increased from 4mm (Vj-tip : 8.14 km/s) to 12mm (Vj-tip : 6.7 km/s). It was also realized that in case of wave shaper warhead there is more than 15% increase in jet tip velocity and 10% increase in jet length in comparison to without wave shaper warhead due to increase in collapse velocity of liner elements. The slug velocity is 1.22km/s in case of with wave shaper warhead whereas it was 1.05 km/s in without wave shaper. It means that a decision for the selection of liner geometry and dimensions of a shaped charge penetrator should be done according to target, required desired effect on target, permissible weight and available space for the warhead.