International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Comparison of numerical methods for modeling the impact of an explosion on a metal plate such as LOAD_BLAST; LOAD_BLAST_ENHANCED; Arbitrary Lagrangian-Eulerian; Particle Blast Method; Smooth Particle Hydrodynamics which are implemented in the program LS-DYNA. The adequacy and accuracy of these methods are evaluated depending on the distance ratio to the explosive charge. The advantages and disadvantages of each method and recommendations for their use based on the results of this modeling and the experience of the authors of thisarticleare presented..

In the report is explored employment of armament design information technologies for education purposes and usage of automation, calculation, design and engineering methods for analysis and testing of armament models in virtual environment.

The current paper presents numerical approach of velocity performances estimations for the EFP (Explosively Formed Projectiles). The proposed method mathematically develops velocities parameters of a particular segment for EFP liner propelled by explosive process. The numerical method is developed, to provide estimations about behavior of projectile vs. time in the EFP forming process powered by explosion. The model is valid for performances estimations of EFP warheads and design data for optimal EFP configuration. Simulations are supported by the software Autodyn for numerical modeling respectively. The obtained numerical results are compared with the available experimental data.

The experiment report presents the results of the field tests of fiber-reinforced concrete (FRC) and reinforced concrete specimens which were performed by research team from Faculty of Civil Engineering, Czech Technical University in Prague, Czech Republic in cooperation with the Czech Army corps in the military training area Boletice. The tests were performed using real scale reinforced concrete precast slabs (6×1.5×0.3m) with varying fibre content, fibre type, fibre strength and concrete strength class and 25 kg of TNT charges placed at a distance from the slab for better simulation of real in-situ conditions. The slabs were recorded using a high speed framing camera during the blast loading. The instrumentation enabled us to study the propagation of the blast shock wave through the material, propagation of the cracks on the soffit of the specimen and the final collapse of the middle part of the slab exposed to blast loading. The sequence of the structural behaviour is documented in detail and verified by numerical modelling using the LS-DYNA solver.

Field tests of fiber-reinforced concrete (FRC) and reinforced concrete specimens were performed by research team from Faculty of Civil Engineering, Czech Technical University in Prague, Czech Republic in cooperation with University and the Czech Army corps in the military training area Boletice. The test were performed using real scale reinforced concrete precast slabs (6 x 1.5 x 0.3m) with varying fiber type, fiber strength, fiber content and concrete strength class. TNT charges of 25kg placed at distance from the slab for better simulation of real in-situ conditions. The paper presents conclusions from sets of tests from 2016 and three previous in 2010, 2011 and 2013. Eleven specimens were tested in total. Two specimens were without fibres and had different concrete strength. Polypropylene fibres (PP) with length 50mm and strength of 600MPa and steel fibers (FE) with low ductility 25mm long and strength 400MPa were added in different content (0.5% and 1%) to the other nine specimens.

The error of aviation bombs mission use is sum of aiming error and technical scattering error. Technical scattering full error is sum of partial errors. Technical scattering full error of aviation bomb for ejection release is determined.

The article deals with a fundamentally new methodology for optimization, assessment, and control of the roughness of surfaces that can be applied in all production facilities. What is meant by optimization is the choice of the most appropriate roughness from among all the practically possible values that can be achieved in certain production conditions. The given methodology is used as a basis for the assessment of the influence of surface roughness on the strength of a joint formed through the process of hot pressing.