Young’s modulus is a key parameter of materials. The method of its calculation in the current paper is concerned with the mismatch of the mechanical impedance at the bar/specimen interface for a compression SHPB (split Hopkinson pressure bar) test. By using long and thin specimens, the signal recorded in the transmission bar presents itself as a multistep signal. The ratio between the heights of two successive steps represents the experimental data that are considered in the formula of the elastic modulus this article is devoted to. The oscillatory nature of the real signals on the horizontal or quasi-horizontal segments prevents a precise determination of the two successive step heights ratio. A fine tuning of this value is made based on the characteristic time necessary for the signal to rise from one level to the next one. The FEM (Finite Element Method) simulations are also used in calculation of the Poisson coefficient of the tested complex concentrated alloy.

In this paper, a solid propellant grain concept was defined, obtained through additive manufacturing, which combines characteristics of multilayer elements with those of tubular geometric shape. The internal ballistics model adapted for such a solid propellant grain configuration allowed the calculations and highlighted the possibility of obtaining a pressure-time curve with a slightly increasing variation (progressive burning). The case studies carried out had as their starting point the existing physical configuration of the solid rocket motor for S-5K unguided ammunition. For the latter, PRTF-100 double base propellant was replaced by a composite propellant consisting of 87.3 wt% ammonium dinitramide, 10.7 wt% polycaprolactone and 2 wt% copper oxide.

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