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Influence of Liner Wall Thickness on the Penetration Performance of PETN-HTPB PBX-based Shaped Charges into Steel Targets

Elshenawy Tamer, Ezzat Eldesoky, Riad Ahmed M., Elkader Mohamed Abd

Central European Journal of Energetic Materials

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2022

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Vol. 19, no. 1

63--90

EN

The thickness of a shaped charge liner is one of the essential parameters that must be considered when optimizing penetration depth into a target material. In this paper, experimental and analytical studies have been implemented using shaped charges having copper liner thicknesses ranging from 0.7 to 1.3 mm in an optimization study of the influence of jet characteristics on the achieved penetration depths into steel targets. The shaped charges were filled with equal masses of PETN-polyurethane based PBX explosive charges and fired against steel targets placed at 29 mm stand-off distance. The experimental measurements show that the depth of jet penetration into steel targets increased with liner thickness up to a thickness of 1.1 mm, after which the penetration decreased again. A numerical study was also carried out using the hydrocode Autodyn to model the jets used in the optimization analysis, which accounted for the variation of penetration depth using different liner thicknesses. This analysis also showed why the penetration depth achieved with a liner thickness of 1.0 mm was not optimum due to its non-coherent formed jet. Instead, a liner with a wall thickness of 1.1 mm exhibited the optimum penetration depth of 12.8 cm.

2

Experimental Study of the Effectiveness of a Model Reactive Armour without Metal Plates

Trzciński Waldemar A., Zalewski Karol, Chyłek Zbigniew, Szymańczyk Leszek

Central European Journal of Energetic Materials

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2022

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Vol. 19, no. 2

113--134

EN

Explosive reactive armour (ERA) is widely used to protect military vehicles against shaped charges and kinetic projectiles, but the use of the ERA element with metal plates is potentially hazardous to the surroundings. A patent claim has recently been issued on explosive reactive armour without metal plates. The non-metallic ERA consists of an explosive, a heavy metal powder and a binder. The aim of the present work was to experimentally test the effectiveness of such armour for disrupting cumulative jets. HMX was used as the explosive matrix and RTV silicone as the binder. Tungsten (W) powder was added to the explosive. The disruption of the cumulative jet was assessed on the basis of X-ray images, the number and size of holes in a steel plate, which was placed under the shaped charge, and the penetration depth of a steel target. It was shown that reactive armour consisting of HMX and W powder was effective in dispersing the cumulative jet, especially for a small impact angle (30°). The influence of the W particle size and the content of the W powder in the armour on jet were investigated. Finally, the effectiveness of one of the tested reactive armours was compared with that of classic reactive armour with steel plates.

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Application of BCHMX in Shaped Charges against RHA Targets Compared to Different Nitramine Explosives

Elbeih A., Elshenawy T., Zeman S., Akstein Z.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 1

3--17

EN

In this work, a new bicyclic nitramine, cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (bicyclo-HMX or BCHMX), has been tested for its performance as a shaped charge explosive filler in comparison with three other interesting cyclic nitramines. Four shaped charges were prepared using different nitramine-based plastic bonded explosives (PBXs), and their performance was measured experimentally in terms of the penetration depth into laminated rolled homogeneous armour (RHA) targets. The explosive fillers were highly pressed PBXs based on RDX, HMX, BCHMX and CL-20, bonded by Viton A binder. The Autodyn numerical hydrocode was implemented to determine the shaped charge jet’s characteristics and its penetration depth. The experimental and calculated detonation characteristics of the explosives used are reported. Relationships between the detonation characteristics of the explosives and the jet characteristics were observed. The results show that CL-20 is the most powerful explosive, with the largest penetration depth into the RHA target, while BCHMX explosive has a relatively enhanced penetration depth with respect to RDX explosive. The results of the Autodyn code calculations are consistent with the experimental measurements, with a maximum difference of 6.6%.

4

A Modified Penetration Model for Copper-Tungsten Shaped Charge Jets with Non-uniform Density Distribution

Elshenawy T., Elbeih A., Li Q. M.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 4

927--943

EN

The penetration of a shaped charge jet with non-uniform density distribution was studied. The virtual origin model, which assumes a constant jet density, was modified to include the situation where the jet density deficit/reduction of an un-sintered copper-tungsten powder jet causes a non-uniform jet density distribution. A relation between the relative density ratio and the normalised jet velocity is proposed, based on which an analytical solution of the modified virtual origin model is obtained. The validity of the modified virtual origin model was demonstrated by its largely improved prediction in comparison with experimental and numerical results. It showed that the density reduction term reduces the penetration depth by 16.58% for an un-sintered copper-tungsten powder jet.