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1

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%.

2

Performance and Detonation Characteristics of Polyurethane Matrix Bonded Attractive Nitramines

Elbeih A., Wafy T. Z., Elshenawy T.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 1

77--89

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.

3

Concerning the shock sensitivity of cyclic nitramines incorporated into a polyisobutylene matrix

Pelikán W., Zeman S., Yan Q. L., Erben M., Elbeih A., Akštein Z.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 2

219--235

EN

Two types of plastic bonded explosives (PBXs) based on ε-2,4,6,8,10,12hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (ε-HNIW, CL-20), and PBXs based on 1,3,5-trinitro-1,3,5-triazinane (RDX), β-1,3,4,7-tetranitro-1,3,5,7-tetrazocane (β-HMX) and cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (bicycloHMX, BCHMX) were prepared using a polyisobutylene binder with dioctylsebacate (DOS) as plasticizer, i.e. a C4 matrix. One version of the ε-HNIW PBX is a product with reduced sensitivity (RS-ε-HNIW). All these PBXs, referenced respectively as RS-ε-HNIW-C4, ε-HNIW-C4, RDX-C4, HMX-C4 and BCHMX-C4, were tested using the Small Scale Gap Test according to STANAG 4488. The results of the gap test on the PBXs with RDX, β-HMX and BCHMX correspond to the impact sensitivities of the original crystalline nitramines. This is not entirely valid for ε-HNIW. In other words, PBXs with RS-ε-HNIW cannot achieve as low a shock sensitivity as would be expected from the differences obtained from the impact sensitivities between RDX, β-HMX and BCHMX, on the one hand, and RS-εHNIW on the other. It is shown that the morphological stability of RS-ε-HNIW in the C4 matrix is insufficient. However, further development and use of RS-ε-HNIW as a filler of PBXs would seem to be both desirable and beneficial. Despite the relatively high impact sensitivity of crystalline BCHMX, the shock sensitivity of its analogous C4 PBX is already good, and comparable with that of RS-ε-HNIW.

4

Characteristics of Melt Cast Compositions Based on cis-1,3,4,6-Tetranitrooctahydroimidazo-[4,5 d] imidazole (BCHMX)/TNT

Elbeih A., Zeman S.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 4

501--513

EN

cis-1,3,4,6-Tetranitrooctahydroimidazo-[4,5 d]imidazole (BCHMX) is a new bicyclic nitramine which has been prepared using a two-stage synthetic method. In this work, a new melt cast composition based on BCHMX/TNT (60/40 by wt.) was prepared. For comparison purposes, Composition B based on RDX (1,3,5-trinitro1,3,5-triazacyclohexane)/TNT (60/40 by wt.), and HMX (1,3,5,7-tetranitro-1,3,5,7tetraazacyclooctane)/TNT (60/40 by wt.) were also studied. Impact and friction sensitivities of these compositions and of the individual explosives were determined. The detonation velocities were measured experimentally. The performance of the compositions prepared was studied by measuring the brisance using the Kast method. The detonation parameters of the compositions and the individual explosives were calculated using the EXPLO5 thermodynamic code. The results show that mixing these nitramines with TNT decreases their sensitivities. BCHMX/TNT is more sensitive to impact and friction than Composition B while it has higher detonation parameters, at the same level as HMX/TNT. In comparison, BCHMX/TNT has the highest relative brisance of the compositions studied. It is postulated that the higher performance characteristics of BCHMX and compositions based on it, in comparison with those of HMX, are due to a higher positive heat of formation for this nitramine.

5

Effect of Different Polymeric Matrices on the Sensitivity and Performance of Interesting Cyclic Nitramines

Elbeih A., Zeman S., Jungova M., Akstein Z.

Central European Journal of Energetic Materials

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2012

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Vol. 9, nr 2

131-138

EN

Different polymeric matrices, based on butadiene-styrene rubber, polymethyl-methacrylate and silicone binders, were investigated for their ability to decrease the sensitivity of explosives to different mechanical stimuli. A series of plastic explosives based on four different nitramines, namely RDX (1,3,5-trinitro- 1,3,5-triazacyclohexane), β-HMX (β-1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane), BCHMX (bicycloHMX, cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5- d ]imidazole) and ε -HNIW (ε -2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ε-CL-20), bonded by the selected polymeric matrices were prepared. Sensitivity to impact of all of the plastic explosives prepared as well as of the pure explosives, was measured using the fall hammer test. Sensitivity to friction was determined using the BAM friction test. The performance was studied using the ballistic mortar test and the results were recorded relative to TNT (trinitrotoluene) as reference. By comparing the results of impact and friction sensitivities, it is obvious that the mechanism of transfer of the friction force to the reaction center of the nitramine molecule should be different from that of impact energy transfer. The silicone binder appeared to be the best polymer for decreasing the sensitivity of explosives. The results of the ballistic mortar proved that the performance of the plastic explosives prepared is affected by the type and weight percentage of the binder in each sample.

6

Thermal Stability and Detonation Characteristics of Pressed and Elastic Explosives on the Basis of Selected Cyclic Nitramines

Elbeih A., Pachmáň J., Zeman S., Trzciński W. A., Akstein Z., Sućeska M.

Central European Journal of Energetic Materials

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2010

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Vol. 7, nr 3

217-232

EN

Bicyclo-HM X (cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d] imidazole or BCHM X) was studied as a plastic explosive bonded with the C4 matrix and with Viton A. Also a series of nitramines namely RDX (1,3,5-trinitro-1,3,5=triazinane), HM X (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) and HNIW (ĺ-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ĺ-CL-20) were studied for comparison with the same types of binders. The detonation velocity, D, of all prepared mixtures was measured. Their thermal stability was determined using non-isothermal differential thermal analysis (DTA). While the C4 matrix lowers the thermal stability of the resulting explosives, Viton A enhances this stability. Approximate relationships between the peaks of exothermic decomposition and the D values were found. The detonation parameters were also calculated by means of Kamlet & Jacobs method, CHEETAH and improved EXPLO5 code for all the mixtures. From the measured D values and the calculated detonation parameters, it is obvious that the detonation parameters of BCHM X-mixtures are very close to HM X-explosives and better than those of RDX-mixtures. It was found that the C4 matrix reduces the difference between the values of energy of detonation in the studied C4 mixtures. As expected, the pressed HNIW-Viton A mixture has the highest detonation parameters of all of the prepared mixtures.