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Explosively Formed Penetrators Inflight Heating Compared to Hemispherical Copper Shaped Charge Jet

Abdelkhalek Sherif M., Abdelhafiz Mahmoud, Ismael Shukri, Elbasuney Sherif, Elshenawy Tamer

Central European Journal of Energetic Materials

2024

Vol. 21, no. 2

188--209

Performance of shaped charges jet and explosive formed penetrators (EFP) can be tailored based on initial liner design and geometry. In addition, the jet temperature gradients during liner collapse and jet stretching mechanisms are different in both cases; the EFP and the traditional jet due to the different strain rates caused by the velocity gradient. In the current research work, oxygen free high conductivity copper (OFHC) was employed with two different liner geoemtries including hemispherical and dish-shaped liners of 2 mm thickness and 33 mm charge diameter. Autodyn numerical modeling was employed to study the impact of liner geometry on the characteristics of produced jet. Moreover, the jet heating mechanisms have been investigated numerically; the ratio between the collapse heating temperature to the plastic deformation temperature was found to be 1.61 and 0.43 for the dish-shaped and hemispherical jet respectively. This finding means that the jet heating due to stretching is not predominant one in both EFP and jet as it has already been confirmed in the papers published so far. Furthermore, EFP and jet penetration performances were assessed by the static firing against 4340 steel targets; while dish-shaped demonstrated shallow but enhanced wide crater at large standoff distance (D), i.e. 30D. Hemispherical jet has achieved large penetration depth with small crater diameter at small standoff distance, i.e. 4D.

Hemispherical Zirconium Liner for Advanced Shaped Charge with Enhanced Behind Armour Effect

Elshenawy Tamer Abd Elazim, Elbasuney Sherif

Central European Journal of Energetic Materials

2021

Vol. 18, no. 3

293--321

Armour penetration is an essential outcome for shaped charges, especially when the behind-armour effect is considered. Hemispherical liners produce superior jet mass compared with those of traditional conical shape. In this paper two different materials have been studied as hemispherical shaped charge liners. The reference liner was hemispherical oxygen-free high-conductivity copper (OFHC); the other liner material was zirconium. These liners were experimentally tested against 4340 steel targets in shaped charges loaded with the same amount of Composition B explosive. Zirconium liners were found to offer superior performance with experimental penetration and crater diameter respectively 16% and 20% greater than OFHC. Ansys Autodyn hydrocode simulation results demonstrated that both liners produced superior jet masses exceeding 50% of the total liner mass. Moreover, zirconium had a jet tip velocity of 4869 m/s compared with 3886 m/s for OFHC. Additionally, zirconium had a superior average jet collapse to plastic deformation temperature ratio of 0.73 compared with 0.34 for OFHC. This is the first time the relation between the jet temperature during collapse and jet stretching has been reported.