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Open access

Juris Maklakovs, Jevgēnijs Tereščenko and Vladimirs Šestakovs

Abstract

In the field of security in transport distinguish risks related to flight safety and aviation security. Safety of flights is ensured through the reliability of aviation equipment and the qualification of the personnel who services and operates it, aviation security is a condition of protection from illegal interference in its activity. Risk management in civil aviation in the field of security is a relatively new direction of activity. Deep research in this area began only at the beginning of the XXI century. It is quite difficult to use the existing experience of risk management, accumulated in other spheres, as civil aviation has significant features. Various methods and schemes can be used to assess risks. The article discusses various options for predicting risks using the “event tree” and “risk factor tree” methods.

Open access

Darula Radoslav and Sorokin Sergey

Abstract

The analytical model of a fluid filled cylindrical shell is used to analyse the wave propagation in the quarter wavelength absorbers. It has been found, that due to the strong fluid-structure interaction, the considerable wave speed reduction can be reached using a compliant shell. Thus via parametric studies, the dimensions of the absorbers are assessed to reach more efficient and compact design. Furthermore, the use of the compliant materials allows treating the fluid to be incompressible, which helps to simplify the calculations.

Open access

Kunz Jan, Čala Martin, Pikula Stanislav and Beneš Petr

Abstract

The aim of this paper is to design, implement, test and compare several tracking filtration methods for predictive maintenance of a jet engine. Based on literature review multiple possible methods are described. Appropriate ones selected for further implementation are peak filtration, coherent demodulation, Vold-Kalman filtration and order analysis. Methods are tested to meet criteria set by an aircraft manufacturer and compared using simulated signals.

Open access

Jančo Roland and Darula Radoslav

Abstract

The article deals with the contribution of Prof. Ing. Pavol Élesztős, CSc. in the field of engineering. He was born in 1948, studied and subsequently remained at the Faculty of Engineering at the Slovak University of Technology in Bratislava since 1968. Under his leadership 6 dissertation theses were defended in the study program of Applied Mechanics. He is the author of 1 monograph, co-author of 2 monographs, author of 30 reviewed scientific articles in journals, and over 250 original scientific papers published in domestic and foreign conference proceedings. Professor Élesztős is currently a Professor Emeritus and is known as a talented teacher.

This article is a celebration of prof. Ing. Stanislav Žiaran’s, CSc. contribution to the field of engineering. Born in 1948, since 1966 he studied and subsequently continued his academic career at the Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava. He has supervised 2 dissertation and 42 diploma theses, which were successfully defended in the study programs Applied mechanics and Mechatronics. Prof. Žiaran is the author to 5 monographs, 9 textbooks, 13 university textbooks, 6 manuals for the engineering industry and more than 290 original scientific papers published in domestic as well as international journals and conference proceedings. He has translated of 111 ISO and EN standards, 107 research reports for practice and he is the editor of 20 peer-reviewed scientific proceedings Noise and Vibration in Practice. He also presented 16 requested lectures at world congresses abroad. Prof. Žiaran is a gifted teacher of mechanics and his students appreciate his enthusiasm and knowledge he is sharing with them.

Open access

Pleban Dariusz and Mikulski Witold

Abstract

Two test stands for determining sound insulation in the frequency range above 5 kHz were made. One consisted of two horizontally adjacent reverberation rooms and a special source of high frequency sounds and ultrasounds. The other test stand consisted of a miniaturized test chamber and a special source of ultrasounds. The paper presents results of the preliminary measurements of sound insulation properties of different barriers in the frequency range above 5 kHz.

Open access

Trebuňa František, Bocko Jozef, Pástor Miroslav, Lengvarský Pavol and Prada Erik

Abstract

The paper deals with design and computation of precise positioning mechanism. The aim of mechanism is to transfer applied load without any change of position of parts in question. The stabilization of position is assured by elastic elements connected to reductor which is adjusted into correct position by an actuator. The functionality of mechanism and its stiffness and strength characteristics were checked by the finite element method. The computations were accomplished for prescribed displacement of reductor. On the base of this type of loading the behaviour of the structure was evaluated.

Open access

Vizi Máté Benjámin and Stépán Gábor

Abstract

Traditionally, the Furuta pendulum was used for testing advanced control strategies on a simple nonlinear and underactuated structure. In this paper, we investigate analytically and experimentally the dynamical description of the Furuta pendulum focusing on the effect of dry friction on a special bifurcation behaviour of the downward equilibrium position.

Open access

Cross-Coupled Heat and Moisture Transport Part 2/1: Applications in Mechanics

Electrical Analogy – Analytical Solution – Experiments

Szekeres Andras and Fekete Balazs

Abstract

Based on the theory laid down in the Part 1 [1] in this paper we are going to display applications in physics and especially in mechanics. After a short summary on coupled fields in mechanics, we generally analyze the analogies in mechanics. As the most important, the electrical analogy is discussed in details. By the electrical analogy based analytical solution we display the results of the coupled thermo-hygro problem with second sound. Finally, a few experiments are discussed, eg. experiments by electrical analogy, experiment on diffusivities, experiment on relaxation time, experiment on hydroglobe. This latter one leads to the engineering application of the problem.

Open access

Tůma Jiří, Šuránek Pavel and Žiaran Stanislav

Abstract

The problem of active vibration control of weakly damped mechanical structures is potentially unstable modes of vibrations due to the positive feedback for some vibration modes. The paper will discuss the change of positive feedback on the negative one using all-pass discrete-time filters. These filters can be arranged in a cascade to stabilize many potentially unstable modes. The piezoelectric actuator as a source of force is used to damp vibration.