Abstracts of papers for

Previous issue vol. 45, no. 3 (2004)

vol. 45, no. 4 (2004)

Next issue vol. 46, no. 1 (2005)

Contents of issue 4, vol. 45

1. E. Włodarczyk, J. Janiszewski: Static and dynamic ductility of copper and its sinters;
2. E. Włodarczyk, M. Maruszyński: Mathematical model of the temporary pulsating gunshot cavity
3. E. Włodarczyk, M. Maruszyński: Analytical model of the shape of the temporary gunshot cavity
4. R. Ganev, I. Glavchev: IR spectroscopy characterization of single-base propellants during their natural aging

E. Włodarczyk, J. Janiszewski: Static and dynamic ductility of copper and its sinters

The results of experimental investigation concerning the properties of copper and its sinters at different conditions of quasistatic and dynamic deformation (dε/dt=10^-3-10⁴ s^-1) are presented. Dynamical examination was carried out by the annular method (expanding ring test), using the X-ray impulse technique. As it is known, the ductility of the bulk M1E copper at the static loading is higher than the ductility of sintered copper. It seems that at the explosive loading, these dependences are inverse, i.e. the dynamic ductility of the bulk M1E copper is lower than the dynamic ductility of the sintered copper. This fact has been established in the present paper.

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E. Włodarczyk, M. Maruszyński: Mathematical model of the temporary pulsating gunshot cavity

The analytical method, describing the temporary pulsating gunshot cavity, has been presented in this paper. This cavity is simulated with the aid of a pulsating spherical gas bubble in non-viscous, incompressible liquid. The simple algebraic formulae, determining the maximal radius and minimal one of the temporary gunshot cavity, have been derived. It seems that the maximal radius, R₁, is an explicit function of the impact velocity of a bullet in the ideal liquid, and of the bullet calibre, as well as of the liquid density. The minimal radius, R₂, of the temporary cavity additionally depends on the initial gas pressure within the bubble. Note that the radii R₁ and R₂ do not depend on the bullet mass. The closed algebraic formulae, which determine the velocity, acceleration and pressure fields in the ideal liquid surrounding the temporary cavity, have been obtained, too. The results of the theoretical analysis, presented in this paper, are compatible with the experimental data [1-6, 10, 11, 14].

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E. Włodarczyk, M. Maruszyński: Analytical model of the shape of the temporary gunshot cavity

The analytical method, describing the shape of the temporary pulsating gunshot cavity, has been presented in this paper. A non-viscous incompressible liquid approximates the tissues of the living organism. The simple algebraic formula, determining the trajectory of the rigid projectile penetrating into incompressible liquid, has been derived. The shape of the temporary gunshot cavity is determined with the aid of envelope of the expanding bubbles family. The centers of the bubbles are placed along the projectile trajectory. The results of the theoretical analysis, presented in this paper, are compatible with the experimental data.

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R. Ganev, I. Glavchev: IR spectroscopy characterization of single-base propellants during their natural aging

Single-base propellants stored for more than 50 years were investigated by quantitative IR spectroscopy. The natural aging of the propellants was made in military storehouse for 9, 12, 18, 29, 36, 40, and 51 years. The change in the propellants was characterized by IR spectra. The most suitable absorbances for qualitative IR analysis of -OH and -NO₂ groups and of internal standards were determined. The hydrogen bonds formation was characterized by the shift of the bonds the peak width at half-height.

Keywords: propellants, IR spectroscopy, aging, nitrocellulose.

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