Wyniki wyszukiwania - BazTech

1

Theoretical and Experimental Study on Detonation Wave Propagation in Cylindrical High Explosive Charges with a Wave-shaper

Pan J., Zhang X., He Y., Deng Q., Guan Z.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 3

658--676

EN

The use of a cylindrical high-explosive charge with a wave-shaper is an efficient way to obtain an ultra-high pressure and a convergent detonation wave. An analysis of flow fields corresponding to the regular and Mach reflection of detonation waves in a cylindrical high-explosive charge with a wave-shaper is presented in this paper. The pressure, flow velocity and triple point growth angle of the Mach stem were calculated. The Mach stem height was also determined by using the modified Whitham method. The results show that the Mach stem height rises from zero at the critical angle of Mach reflection and changes to the Chapman-Jouguet detonation state with the propagation of the detonation waves. Shock indentation experiments were conducted, in which a wave-shaper was used in a cylindrical high-explosive charge to form Mach reflection detonation waves. The results showed that the discrepancy between the experimental results and the theoretical calculations was less than 15%, which proves the validity of the proposed theoretical model.

2

Numerical simulations of blast loads from near-field ground explosions in ai

Dobrociński S., Flis L.

Studia Geotechnica et Mechanica

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2015

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Vol. 37, nr 4

11--17

EN

Numerical simulations of air blast loading in the near-field acting on the ground have been performed. A simplified blast model based on empirical blast loading data representing spherical and hemispherical explosive shapes has been simulated. Conwep is an implementation of the empirical blast models presented by Kingery and Bulmash, which is also implemented in the commercial code LS-DYNA based on work done by Rahnders-Pehrson and Bannister. This makes it possible to simulate blast loads acting on structures representing spherical and hemispherical explosive shapes of TNT with reasonable computational effort as an alternative to the SPH and Eulerian model. The CPU time for the simplified blast model is however considerably shorter and may still be useful in time consuming concept studies. Reasonable numerical results using reasonable model sizes can be achieved not only for modelling near-field explosions in air but most areas of geotechnical. Calculation was compared with blast SPH and Eulerian model.

3

Directional Warhead Design Methodology for a Tailored Fragment Beam

Dhote K. D., Murthy K. P. S., Rajan K. M., Sucheendran M. M.

Central European Journal of Energetic Materials

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2015

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Vol. 12, no. 4

637--649

EN

In this article, the authors present a design methodology for generating a spatially tailored fragment beam with specified velocity and projection angles. The modified Gurney equation was used to estimate the length and diameter of the cylindrical charge to achieve the desired velocity; and the modified Taylor equation was used to arrive at the radius of curvature of the fragmenting disc. The methodology is further explained for generating a rectangular beam of fragments having a velocity of 1500 m/s with a tailored fragment beam of 32° in the azimuth and 20° in the elevation. The warhead had preformed steel fragments of 4 mm diameter arranged in a double layer. The design was validated using the fragment distribution measured experimentally.

4

A New Thermally-stable Insensitive High Explosive:N,N′-Bis(1,2,3,4-tetrazol-5-yl)-4,4′-diamino-2,2′,3,3′,5,5′,6,6′-octanitroazobenzene (BTeDAONAB)

Mousavi S., Esmaeilpour K., Keshavarz M. H.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 4

455--465

EN

A novel high performance explosive compound, N,N′-bis(1,2,3,4-tetrazol5-yl)-4,4′-diamino-2,2′,3,3′,5,5′,6,6′-octanitroazobenzene( BTeDAONAB), is introduced which is a thermally stable, insensitive high explosive. The presence of −NH2, −N=N− groups and the tetrazole ring simultaneously in the BTeDAONAB unit surprisingly increases its thermal stability. For the identification and characterization of BTeDAONAB, different analytical techniques have been used, including melting point, IR, 1H NMR, 13C NMR spectroscopy, elemental analysis, differential thermal analysis (DTA), thermogravimetry (TG), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The sensitivity and detonation properties of BTeDAONAB were compared with 2,4,6-triamino1,3,5-trinitrobenzene (TATB) and N,N′-bis(1,2,4-triazol-3-yl-)-4,4′-diamino2,2′,3,3′,5,5′,6,6′-octanitroazobenzene (BTDAONAB), two well-known, thermally stable, insensitive high explosives, as well as hexanitrostilbene (HNS). These studies show that BTeDAONAB has favorable thermal stability with high performance.

5

Rate of the energy release in high explosives containing nano-size boron particles

Kanel G. I., Utkin A. V., Razorenov S. V.

Central European Journal of Energetic Materials

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2009

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Vol. 6, nr 1

15-30

EN

With a goal to obtain information on rate of the high explosive decomposition and equation of state of the HE formulations and detonation products, measurements of the pressure and particle velocity profiles of shock and detonation waves have been performed for pure coarse-grain and fine-grain HMX and for the HMX+16.4% boron mixture. For these measurements, the manganin pressure gauges and the laser Doppler velocimeter VISAR were applied. Effect of boron in the energy release process was observed both in the detonation and shock-wave initiation regimes.

6

The Possibility of the Use of High Explosive Layers in Ram Accelerators

Kobiera A., Wolański P.

Archivum Combustionis

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2008

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Vol. 28 nr 3-4

149-171

EN

The possibility of the use a high energetic solid material in a ram accelerator is discussed in this paper. First, some facts about multiphase combustion observed in ram accelerators are presented. While the core problem of using high explosive in supersonic propulsion is fast combustion, the first stage of work consisted of measuring ignition delays of selected high explosives. The ignition is triggered by a passing detonation wave. The experimental results proved that those materials can be applied to the ram accelerator and PETN has been selected as the best material. Next, a numerical model of ignition and combustion of a high explosive layer in a ram accelerator has been created and applied in numerical simulations. The obtained results allowed estimations of thrust enhancement and parametric analysis of the influence of some parameters on performances of the device. It was found that use of layers of high explosive can increase the generated thrust by about 10%. However this depends on such parameters as the speed of the projectile, initial pressure of the gaseous mixture, and the geometry of the projectile.

7

Ekonomiczno-techniczne, prawne i środowiskowe uwarunkowania górnictwa skalnego

Modrzejewski S.

Górnictwo Odkrywkowe

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2004

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R. 46, nr 1

90-92

PL

Przedstawiono wyniki dyskusji podsumowującej omawianie najważniejszych problemów i barier rozwojowych jednej z podstawowych gałęzi zaplecza surowcowego opartego na odkrywkowym przemyśle wydobywczym. Scharakteryzowano na tle podstawowych wskaźników krajów Unii Europejskiej perspektywy oraz uwarunkowania funkcjonowania zakładów górniczych. Przedstawiono problemy prawne i procedury utrudniające pozyskiwanie terenów pod eksploatacją oraz dotyczące zagospodarowania i rekultywacji terenów poeksploatacyjnych. Na tle uwarunkowań technicznych eksploatacji wskazano na kierunki usprawnień prawnych i organizacyjnych związanych z urabianiem złóż materiałami wybuchowymi i wdrażaniem nowoczesnych i innowacyjnych technologii. Wskazano na rolę i możliwości usprawnienia efektywności ekonomicznej wydobycia poprzez korektę opłat eksploatacyjnych. Omówiono kierunki działań pod kątem integracji europejskiej.

EN

Paper presents results of discussion summarizing largest obstacles and development barriers to one of basic branches of resource industry based on open pit mining. Perspectives and operational constraints of mining enterprises were characterized on the base of major indexes of EU countries. Legal problems, procedures making difficult new land acclamation for mining activities, land development, and mining areas reclamations problems were presented. On the background of mining technical constraints, rationalization direction was indicated leading to changes in legal, organizational -rock blasting mining, and implementation of new and innovative technologies. Level of royalty fees was also presented as a factor for improvement of effectiveness of rock mining was discussed as well as direction of activities related to European Integration.

8

Confined explosions of high explosives

Trzciński W., Paszula J.

Journal of Technical Physics

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2000

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Vol. 41, no 4

453-470

EN

In the present paper, effects of turbulent combustion of the detonation products of high explosives in confined explosions are studied. Explosions of TNT, TNT/RDX and the mixtures of these explosives with Al are investigated in a steel chamber of 150-liter volume. The chamber is filled with nitrogen or air under normal conditions. Overpressure histories are recorded at the chamber wall. The dependence of the mean overpressure on the loading density of TNT is determined. This dependence is used to determine the TNT equivalent of explosives tested for confined explosions. On the basis of the measured overpressure histories and the results of thermochemical calculations, the rate of energy release and final heat effects of combustion of the detonation products in air are also estimated. Finally, the degree of after-burning of the detonation products is calculated for explosive mixtures tested.

9

Brisance of the high explosives

Włodarczyk E.

Journal of Technical Physics

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2000

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Vol. 41, no 4

343-359

EN

The essential survey of the literature data, concerning the brisance of high explosives (HE) has been made in this paper. It is confirmed that the quantitative criteria of the theoretical estimate of the HE brisance proposed in the scientific literature are based on several assumptions, which are contradictory to the real course of the explosion phenomenon, and therefore they are erroneous. These criteria must not be applicated in the engineering practice. The reflection process of the detonation wave from th inertial rigid partition was used in order to derive the new formula describing the relative brisance of the HE. Moreover, the brisance of numerous commercial explosives and the military ones has been analysed too. The results, presented in this paper, are confirmed by experimentally gained data.