Analysis of a self-centring detonation wave generator

The aim of the study was to determine the parameters of a detonator generating a self-centring detonation wave, based on experimental and theoretical analysis. The methods for manufacturing selfcentring detonation wave generators available in literature were reviewed and a detonator comprised of two explosives was proposed. The detonator geometry was analysed for its ability to centre the detonation wave. A physical detonator model was created and the detonation wave front downstream of the detonator, analysed and the detonator’s capability to compensate an off-centre detonation initiation, evaluated. The wave fronts were recorded using pulsed x-ray radiography. The study showed that the proposed detonator provides a symmetrical initiation of the main charge for the initiation point (location) offset, lower than the assumed maximum offset.

Polymer-bonded secondary explosives

In this paper, a review of the available literature on physical and explosive properties of explosive compositions containing a secondary explosive and a polymer binder (PBX) is presented. The review focused on an analysis of the properties of compositions containing mostly synthetic polymers. The review showed that, at the moment, the most commonly used composition is a hexogen-based explosive bonded with a chemically cross-linked hydroxylterminated polybutadiene. The use of energetic polymers in PBX compositions was observed only in the experimental systems tested on a laboratory scale. The most popular methods of forming compositions include pressing a previously phlegmatized explosive or chemical cross-linking of the composition in the projectile shell. Compositions which can be formed and reloaded using injection machines are known, but due to many limitations, the method is not widely used.

Using thermochemical code EXPLO5 to predict the performance parameters of explosives

Thanks to the development of more powerful computers and efficient numerical techniques, numerical modelling has become a compulsory tool in solving various problems in the field of energetic materials. In cases where measuring techniques are still unable to measure a given parameter, numerical modelling may be the only option of obtaining a value. In addition, numerical modelling helps us to better understand some phenomena, particularly in understanding the influence of input parameters on output results, as well as saving time and money. The thermochemical equilibrium code EXPLO5 is such a tool which enables theoretical prediction of performance of high explosives, propellants and pyrotechnic compositions. The code is used by more than 80 research laboratories worldwide.

Scaled-down test arrangements for characterizing high explosives

Newly formulated explosives and the optimization of explosive mixtures requires an experimental determination of detonation parameters, especially detonation velocity, pressure and metal accelerating ability. Increasing material and labour costs force researchers to reduce test quantities and therefore to develop smaller scale experiments which provide sufficient data to determine an explosive’s properties. Seven test set-ups found in literature are described and compared in this paper.

Modification of HTPB (α,ω-dihydroxypolybutadiene) by esterification, silanization, epoxidation and hydrogenation

Hydroxyl-terminated polybutadiene (HTPB) is a co-monomer used in the production of polyurethanes. Its unique properties make it resistant to frost and give it excellent mechanical properties, especially at low temperatures. Polyurethanes obtained using this method are used in the production of propellants for space and military rocket propulsion systems, frost-resistant adhesives and insulation materials. Current research on the choice of binder indicates use of highenergy polymers or the modification of previously used polymers aimed at improving their properties. In modern rocket propulsion materials, the polymer binder may be replaced with a suitable high-energy compound, i.e. a polymer including energy groups, e.g. azide or nitro group. The article presents the results of research on methods of modifying HTPB properties to widen its applicability.

New energetic materials derived from common explosives. Review

The review discusses the products of 2,4,6-trinitrotoluene reactions which have explosive properties or are potentially high-energy compounds. The following compounds are discussed: trinitrobenzene, cyanotrinitrobenzene, trinitroxylene, aminotrinitrotoluenes, trinitronitromethylbenzene, methylene bis(2,4,6-trinitrobenzene), hexanitrostilbene, nitromethyldiphenylamines, 4,4’,6,6’-tetranitro-2,2’-azoxytoluene and 2,4,6-trinitrobenzylideneamine derivatives. The synthesis pathways are provided for all compounds and the detonation parameters are presented for selected compounds.

Preliminary analysis of ballistic requirements for LOVA propellants for new generation tank ammunition

At the end of 2016, the Scientific-Industrial Consortium (Mesko S.A., Polska Grupa Zbrojeniowa S.A., Warsaw University of Technology, Military University of Technology, Military Institute of Armament Technology) set up an R&D project to develop and manufacture a demonstrator of new generation critical components for a 120 mm Polish tank munition. The critical elements for the project included a combustible charge case, an insensitive propellant and tungsten rods for subcalibre projectiles. The task of the Military University of Technology was to develop the basic technology and fabricate insensitive LOVA propellants on a laboratory scale (research team of the Faculty of Advanced Technologies and Chemistry) and carry out the ballistic and simulation tests of a 120 mm tank gun using ammunition incorporating the developed LOVA propellant (research team of the Faculty of Mechatronics, Armamen and Aerospace). The article also includes an analysis of available literature on energy and ballistic properties of LOVA and JA-2 propellants. Closed-vessel tests of JA-2 propellant (manufactured by Nitrochemie AG, designation LO5460) were also carried out. The tests were carried out in a 200 cm3 closed vessel. Based on the propellant gas pressure/time records, the propellant force and co-volume, and dynamic vivacity curves were determined. A linear combustion rate coefficient was determined using the measured results of the propellant grain geometry. The authors’ own data enabled the carrying out of preliminary simulation tests of the 120 mm propellant system.

Theoretical and experimental investigations on a rocket propulsion system of projectiles intended for vehicle active protection system

The paper presents the results of a research project carried out at the Military University of Technology aimed at designing a technology demonstrator of an active protection system – a smart counter-projectile for combating anti-tank missiles at a fixed distance from the protected object. Since the design of the counter-projectile head includes electronic components sensitive to high loads, a solid propellant rocket motor was used as the propulsion system. Based on the specification and requirements for the propulsion system, the propellant charge and nozzle dimensions were determined, and the performance properties of the designed system (chamber pressure, thrust with time and total thrust pulse), calculated. The tests and analyses were carried out using the known properties of homogenous solid rocket propellants manufactured in Poland. To verify the results of the theoretical analysis, experimental studies were carried out in collaboration with “GAMRAT” Sp. z o.o. Special Production Plant (Jasło, Poland) to validate the selected solid propellant and the initial assumptions made on the operation of the propulsion system of the designed counter-projectile.

Aspects of nanomaterials for civil and military applications. Part 1. Origins, characteristics and fabrication methods

The study presents general aspects of highly dispersed nano scale materials including their origins, structure, classification, properties and production methods. In the last two decades, the unique properties and phenomena observed for those material has revolutionized the industry with a significant increase in research and the scope of practical applications of nanotechnology in every aspect of our lives.

Synthesis of HTPB using a semi-batch method

Hydroxyl-terminated polybutadiene is widely used in industry for both civil and military applications. In munitions, HTPB is mostly used as a binder for heterogenic rocket propellants and as a component of plastic bonded explosives, as well as a phlegmatizer in explosives sensitive to friction and impact. The wide range of HTPB applications results from the good mechanical properties of HTPB-based polyurethanes, in particular at temperatures down to –40 °C. A synthesis method for HTPB, different from the commonly used semi-batch and continuous methods, is presented. The effect of parameters including reaction temperature, 1,3-butadiene pressure and hydrogen peroxide concentration on the properties of the obtained polymer is determined. The synthesis conditions enabling new HTPB species to be obtained, which meet the requirements for binders used in solid rocket propellants, are specified.