In order to enhance the penetration capability of the shaped charge jet, different liner forms are used. These modifications help to increase the jet tip velocity, as well as to improve the distribution of the kinetic energy. AUTODYN software is used to perform these numerical simulations. Euler solver of the AUTODYN is used to simulate the jet formation and Lagrange solver is used for penetration problem. Numerical results have good agreement with the available experimental results from the literature. For the same charge calibre and main charge length, several liner forms as conical, circle and trumpet are investigated. Results show that the trumpet form has a higher penetration capability than other forms. Distribution of kinetic energy along the liner with variable liner thickness is more suitable to get higher cumulative jet efficiency on the target

This paper is a result of many years of research in the field of the powder gases shockwave overpressure, which occurs during firing from the mortar. The cause of these occurences is a sudden flow of powder gases from the weapon barrel and its expansion in the undisturbed environment. In this paper, an influence of a propellant charge on the overpressure intensity of the shockwave produced by powder gases nearby mortar is shown. The research comprised modelling and computation of the overpressure field around the weapon, in order to determine its intensity and distribution in space and time. With the aim of the real description of the mentioned occurences, the theoretical part was given, and then the numerical modelling of the instantaneous flow of the powder gases from the motrar barrel has been conducted. Experimental results are obtained from the firing experiments with the 120mm mortar. Computation and experimental results are given in the form of a chart of the barrel pressure change and overpressure of powder gases, at the characteristic measuring points around mortar.

This paper presents a numerical study of the effect of main parameters (liner material, explosive charge, stand-off distance and the presence of the wave-shaper), on one hand, on the jet formation, jet velocity and the jet length, and on the other hand, on the penetration depth. We propose a numerical approach to evaluate their effects on the performance of the shaped charge. AUTODYN-2D software is used for numerical simulations of the shaped charge. The multi material Euler solver of the AUTODYN is used for the jet formation investigation, whereas, Lagrange solver is used for the resolution of the penetration problem. Results have shown that the presence of waveshaper increases the shaped charge depth penetration. For the standoff of 6 charge calibres, the jet penetration is found to be deepest. It is found that the jet velocity is proportional to the jet energy, and the penetration is proportional to the liner density. The oblique explosive reactive armor is more efficient for the protection of the main target. Numerical results have a good agreement with the data from available literature-with experimental results for the chosen explosives.

In a paper given, experimental investigations have included the analysis of crack initiation and growth in welded joint of steel for operation at elevated temperatures. For better understanding of the phenomenon of crack initiation and propagation in welded joints of A-204 Gr. A steel, designed for high-temperature and high-pressure application, it is necessary to determine the effect of heterogeneity of microstructural and mechanical properties on fracture toughness and fatigue crack initiation and propagation in welded components. Based on the tests conducted with pre-cracked CT and Charpy size specimens, the effect of heterogeneity of microstructural and mechanical properties of welded joints on fracture toughness and fatigue-crack growth parameters was determined.

This paper resulted from the research of the overpressure of the shock wave of the powder gases, which occurs during firing of the mortar. Work encompasses modeling and computation of the overpressure field. Increasing overpressure around the mortar is analyzed in the case of using the largest powder charges. In order to reduce the overpressure a corresponding technical solution has been proposed. The solution in the form of divergent nozzle has been proposed and it is placed at the barrel muzzle. The paper also analyzes the impact of this solution to reduce the overpressure intensity at the crew position.Computation results of the overpressure of the powder gases, which were obtained by the realization of numerical calculation, based on the application of the finite volume method, were confirmed by the experimental results, achieved in the firing experiments.