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EN
Copper tungsten liner manufactured using uniaxial pressing technique has been characterized numerically and experimentally in comparison with a baseline shaped charge copper liner produced by deep drawing technique. The jet properties resulted from these two shaped charges were different according to their liner types and relevant densities which affect the resultant penetration depths into rolled homogeneous armour (RHA) targets. Different copper-tungsten powder liners have been studied and analysed using Autodyn hydrocode, from which an optimum powder design was chosen based on its maximum jet kinetic energy that can be coherent. The compacted liner elastic properties have been measured using SONELASTIC apparatus, whereas its real density is determined using helium gas pycnometer. Baseline copper liner obtained by deep drawing technique of uniform density exhibited lower penetration depth in comparison with the copper-tungsten liner (higher density powder). Besides, the penetration crater resulted from the powder liner showed clean hole without clogging because there was no massive slug as in the case of the copper liners. Experimental field tests of the two liners against (RHA) targets exhibited different penetrations depths, which have been accounted in this research.
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%.
EN
Several cast-cured plastic bonded explosives (PBXs) based on cyclic nitramines bonded by a polyurethane matrix have been prepared and studied. The nitramines were ε-CL20 (ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ε-HNIW), BCHMX (bicyclo-HMX, cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole), RDX (1,3,5-trinitro-1,3,5-triazacyclohexane) and HMX (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane). The detonation velocities were measured experimentally. The brisance of the prepared compositions was determined by the Kast method. The penetration performance of shaped charges filled with the prepared compositions was measured experimentally. The detonation parameters of the studied compositions and the individual explosives were calculated using the EXPLO5 thermodynamic code. It was concluded that CL20-HTPB has the highest detonation characteristics and performance of all of the prepared PBXs. BCHMX-HTPB is an interesting PBX with performance and detonation characteristics higher than those of RDX-HTPB. A linear relationship between the detonation pressures of the prepared PBXs and their performances in terms of the explosive brisance was observed; while the penetration depths formed by the shaped charge jets depended on the Gurney velocity of the studied PBXs samples.
EN
Plastic bonded explosives (PBXs) based on ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (ε-HNIW), 1,3,5-trinitro-1,3,5-triazinane (RDX), β-1,3,5,7-tetranitro-1,3,5,7-tetrazocane (β-HMX) and cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (BCHMX) were prepared using a hydroxyl-terminated polybutadiene as a binder (HTPB) and cured with hexamethylene di-isocyanate (HMDI). Recently published data for analogous PBXs with a polyisobutylene binder (i.e. a C4 matrix) are also included. All of these PBXs were tested using the Small Scale Water Gap Test according to STANAG 4490, the results of which are directly proportional to the impact and friction sensitivities of the PBXs studied. Reciprocal ratios between the shock sensitivity of these PBXs and their performance were found using the volume heat of explosion as a variable; a semi-logarithmic analogue, using a representative of the detonation pressure (product ρD2) as a variable, has shown an opposite trend for three of these PBXs. A semi-logarithmic relationship between the shock sensitivity of the PBXs and the impact sensitivity of their pure nitramine fillers has confirmed the higher shock reactivity of the C4 PBXs filled with both technical ε-HNIW and RS-ε-HNIW, while for the HTPB PBXs filled with technical grade ε-HNIW, the shock sensitivity found was as expected. The shape and size of the particles should not be a reason for the increased resistance to shock of HMX-C4.
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.
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