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1

Experimental Assessment of Primer Pressure in 9 mm Pistol Ammunition

Fikus Bartosz, Surma Zbigniew, Trębiński Radosław

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2020

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Vol. 11, Nr 2 (40)

25--30

EN

n theoretical simulations of internal ballistics phenomena, the value of pressure generated by the ignition system is required. Typically, the ignition pressure value is assumed to be 3 - 5 MPa. The work presents a measurement stand using a “micro closed vessel”, designed to determine the ignition pressure for 9 mm pistol ammunition. Pressure measurements were made for two types of ammunition, differing in the construction of the ignition system. The results of measurements indicate that the value of the ignition pressure is twice as high as usually assumed. In addition, the mass of the ignition charge was determined, which is used in selected models of internal ballistics. The mass value was at the level of 0.02 g.

PL

W symulacjach zjawisk balistyki wewnętrznej układów miotających wymagana jest znajomość wartości ciśnienia wytwarzanego przez układ zapłonowy. Wartość ta jest istotna z punktu widzenia opisu procesu spalania materiału miotającego w początkowej fazie strzału, co wynika z znaczącego wpływu ciśnienia gazów prochowych na szybkość spalania materiału miotającego. Ten fakt z kolei przekłada się na maksymalną wartość ciśnienia w przestrzeni zapociskowej. Zazwyczaj przyjmowaną wartością ciśnienia zapłonu jest wartość na poziomie 3 – 5 MPa. Niestety w dostępnej literaturze uwidacznia się brak oszacowań wartości ciśnienia generowanego przez spłonkę amunicji strzeleckiej. Biorąc pod uwagę ten fakt, w pracy przedstawiono stanowisko pomiarowe, wykorzystujące mikrokomorę manometryczną, przeznaczone do pomiaru ciśnienia zapłonu dla 9 mm amunicji pistoletowej. Dokonano pomiarów ciśnienia dla dwóch rodzajów amunicji, różniących się budową układu zapłonowego. Otrzymane rezultaty wskazują, że wartość ciśnienia zapłonu jest dwukrotnie wyższa niż zazwyczaj przyjmowana. Ponadto określono masę ładunku inicjującego, która wykorzystywana jest w wybranych modelach balistyki wewnętrznej. Wartość masy kształtowała się na poziomie 0,02 g.

2

On a Certain Method of Determining the Burning Rate of Gun Propellant

Leciejewski Zbigniew, Surma Zbigniew

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 3

433--448

EN

The relation between the burning rate, r, of a solid propellant and the pressure, p, of gases surrounding the burning propellant surface is the basic component of the gas inflow equation. The applicability of a linear form of the burning rate law is limited only to those propellants for which the same pressure impulses, Ip, were obtained during closed vessel tests at different loading densities. To determine the values of the power form of the burning rate law it is necessary to know the values of the energetic and ballistic characteristics of the propellant. In this paper, a method is presented for determining the relation r(p) for which the only input data are the pressure, p(t), of the propellant gases recorded during closed vessel tests (only for a single specific loading density) and information on the shape and geometric dimensions of the propellant grains. An analysis of the possibility of applying the proposed method, through examples of single-base, double-base and multi-base propellants with neutral and progressive characteristics of burning surface changes, was carried out for the purposes of the present study. The qualitative and quantitative results of burning rate analyses prove the validity of the assumptions made.

3

Closed Vessel Investigation of Propellant Ignition Process with Using Capillary Plasma Generator

Michalski J., Leciejewski Z.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2015

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Vol. 6, Nr 1 (19)

19-26

EN

Previous published results of closed vessel investigations indicated that classical primers (electric or percussion with black powder bedding) when used with LOVA propellants cause unstable burning, deflagration or even lack of ignition. CPG is one of the most reliable ignition sources which make possible a reduction of temperature gradient effect and control combustion process. Comparable tests of black powder and plasma ignition in closed vessel with conventional NC propellant were done. Shorter ignition time while using plasma was achieved.

4

Oddities in determining burning rate on basis of closed vessel tests of single base propellant

Leciejewski Z. K.

Journal of Theoretical and Applied Mechanics

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2014

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Vol. 52 nr 2

313--321

EN

The proper determination of parameter values defining the dependence of the burning rate r of smokeless propellant on gas pressures p surrounding the burning grains constitutes one of the goals of experimental pyrostatic (closed vessel) testing. The aim of the hereby paper is the analysis of results of experimental closed vessel tests realized in the context of isolating possible oddities in determining the relation r(p). During the experimental tests, a single base propellant with grains of different or similar combustible layer thickness e1 was burned while implementing identical or various loading conditions. Identical ignition systems were used in both instances. The results of experimental tests and theoretical analysis performed permit a more complete verification of the assumptions with regard to proper realization of pyrostatic comparative tests and prove additionally that closed vessel tests should be focused in the direction of “dedicated” tests.

5

An investigation of the preparation and performance of microcellular combustible material

Yang W., Li Y., Ying S.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 2

257--269

EN

Microcellular combustible materials, based on poly(methyl methacrylate) (PMMA) bonded RDX, were fabricated by the pressure quench method using supercritical CO2. After foaming, the bulk density, porosity, expansion ratio and cell density were analyzed. Scanning Electron Microscopy (SEM) has also been used to investigate the influence of the foaming conditions (temperature, saturation pressure and depressurization time) and the RDX ratio on the porous structure. The skin-core structure was also observed after the pressure quench process. The mechanical sensitivities and burning performance were investigated by the friction sensitivity test, the impact sensitivity test and the closed vessel test, respectively.

6

Evolutionary algorithms for propellants parameters identification

Górniak A., Kaźmierczak A.

Journal of KONES

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2013

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Vol. 20, No. 2

127--133

EN

This paper presents the possibility of the parametric identification of an unknown low energy explosive basing only on its ballistic curve using advanced optimisation algorithm. What was under investigation here was the approach of an explosive replication for the numerical investigation of ANSYS AUTODYN solver. The emphasis was given here for the propellants used in the automotive safety devices. The results of closed bomb testing was compared with its numerical representation. The required parameters to develop a new numerical model of an explosive was identified with the aid of evolutionary algorithm. In order to perform a parametric identification a mathematical model of considered phenomenon is required. Hence, this paper contains a mathematical model of a deflagration process which was the basis for the evolutionary algorithm. The algorithm verified a variety of parameters until the objective function is obtained. In the case of this paper the objective function was a ballistic curve of an unknown explosive which combust under deflagration regime. The results obtained with this method shows good agreement with the closed bomb test of the propellant. Furthermore, advanced optimisation tools such as an evolutionary algorithms, in oppose to most of other optimisations algorithms, enables to find a global optimum. However, the identified function here was found to be unimodal.

7

Comparative closed vessel tests : influence of ignition and loading conditions on propellant burning rate

Leciejewski Z. K.

Materiały Wysokoenergetyczne

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2011

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T. 3

57--63

EN

The most widely used experimental method to determine and to compare energetic and ballistic properties (force, co-volume, coefficients of burning rate law) of different propellants is burning a specific amount of propellant in a closed chamber. The procedure of determining the values of the individual material constants recommends similar conditions of closed vessel investigations like limited range of loading density and determined mass of black powder (igniter material) for determined loading density. There also often occurs the need for performing of closed vessel comparative tests (carried out for two or more numbers of propellants), where one of them serves the role of a reference propellant and in relation to which described are the differences between the characteristics of the remaining propellants are described. Comparative tests of propellants should be understood to be such tests performed for identical loading conditions, including firstly the same closed chamber capacity, mass of the propellant burned (thereby the identical loading density) as well as identical ignition conditions which are understood as the same mass and the same type of igniter material. In the present paper the influence of ignition and combustion conditions during closed vessel tests on possible deviations in determination of burning rate is analysed as a function of incident heat flux.