Вісники та науково-технічні збірники, журнали

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Author: search.filters.author.Lanets, Oleksii

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    Approximate calculation of natural frequencies of oscillations of the plate with variable cross-section of the discrete-continuous inter-resonance vibrating table
    (Видавництво Львівської політехніки, 2022-02-22) Lanets, Oleksii; Maistruk, Pavlo; Maistruk, Volodymyr; Derevenko, Iryna; Lviv Polytechnic National University
    Problem statement. To ensure highly efficient inter-resonance modes of operation of vibrating equipment, the oscillating masses of the system must have certain inertia-rigid parameters, as well as a certain frequency of natural oscillations. The disadvantage of highly efficient inter-resonance oscillatory systems is that the third reactive mass must be small, and therefore the use of complex and large structures is impossible. Therefore, it is best to use the reactive mass as a continuous section. The continuous section, which is a flexible body, optimally combines inertial and rigid parameters. Scientific works have already considered the design of the vibrating table, in which the continuous section is an ordinary rectangular plate hinged in the intermediate mass. This decision looks quite promising. However, likely, the rectangular shape of the plate is not the best option to ensure maximum energy efficiency. Purpose. Extend the method of calculating the natural frequency of oscillations of the plates by the approximate Rayleigh-Ritz method using the general hyperboloid equation to plates with variable cross-section for the proposed types of plates and check the results with the calculation in Ansys software. Methodology. The calculations of the plates were performed using the basic principles of the theory of oscillations, in particular the Rayleigh-Ritz method in the software product MathCAD. Findings (results) and originality (novelty). Two types of elastic plates with variable cross-sections are considered. In the first case, the shape of the plate was given by quadratic functions, in the second case, it was described by trigonometric functions of cosine. In both cases, the same conditions of attachment in the intermediate mass were observed. The calculation of the first natural frequency of oscillations of the considered plates was performed using the approximate Rayleigh-Ritz method with the assumption that the deflection of the plates occurs on the surface of the hyperboloid. The reliability of the obtained results was verified by numerical calculation in the software product Ansys. Practical value. It is assumed that the proposed types of plates can increase the dynamic potential of the vibrating machine. Scopes of further investigations. For further study of the considered types of plates as a continuous section of the inter-resonance vibrating machine, it is necessary to calculate their deflections at forced oscillations.
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    Derivation of analytical dependencies for determining stiffness parameters of vibration isolators of vibratory machine
    (Lviv Politechnic Publishing House, 2020) Lanets, Oleksii; Kachur, Oleksandr; Korendiy, Vitaliy; Lviv Polytechnic National University
    Problem statement. While designing vibration isolators, the essential attention should be paid to the safety factors such as the levels of vibration and noise, as well as to the material and the structure of isolators. In major vibratory technological equipment, there are used full-metal vibration isolators, which can be designed in the form of coil (cylindrical, conical, helicospiral) or flat (leaf-type, disc-type) springs. The problems of stress-strain analysis of metal springs used for vibration isolation of various vibratory equipment are of urgent interest among the designers and researcher. The engineering techniques of step-by-step calculation of full-metal vibration isolators of different types of vibratory technological machines are not thoroughly presented in the modern information resources. Purpose. The present paper is aimed at developing and implementing the detailed algorithm of determining the stiffness parameters of the metal coil springs used for vibration isolation of large-scale vibratory machines. Methodology. The investigations are carried out using the basic laws and principles of solid mechanics and theory of vibrations. The calculations were conducted using MathCAD software; the computer simulation of the spring’s stress-strain state was performed using SolidWorks software. Findings (results) and originality (novelty). The improved design of the vibratory conveyer-separator is considered. The engineering technique of calculating the passive vibration isolators of various vibratory equipment designed in the form of metal coil springs is developed. The proposed technique is implemented while designing the vibration isolation system of the vibratory conveyer-separator. The system’s operational characteristics are determined, and the computer simulation of the springs stress-strain state is carried out. Practical value. The proposed design of the vibratory conveyer-separator can be implemented in various industries (machine-building, chemical, pharmaceutical, food-processing, construction, mining, metallurgy, textile industries etc.) for conveying different loose, bulky and piecewise products, and separating them into fractions of different sizes. Scopes of further investigations. While carrying out further investigations, it is necessary to analyse the influence of the proposed design of vibratory conveyer-separator on the foundation during its operation, and to consider the necessary of applying the additional fixation systems.
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    Impact of street parking on delays and the average speed of traffic flow
    (Видавництво Львівської політехніки, 2020-02-26) Hrytsun, Oleh; Lanets, Oleksii; Solodkyy, Serhiy; Lviv Polytechnic National University
    The article is devoted to the problem of the impact of street parking on delays and the average speed of traffic flow. The sections with different ways of putting vehicles near the roadway in the central part of Lviv city with the most saturated flow were exposed to scientific scrutiny. For this purpose, the program software PTV Vissim is used. The causes of the impact of street parking on traffic flow speed and roadway capacity are analyzed. Simulation model was created, with the use of which the operation of the street section where parking is allowed and without parking, and also the impact of the parking duration on the average speed of traffic flow and its delays were investigated. It is clarified that the least values the average traffic delay has with the parking duration of 900 and 1800 sec, and the biggest values it has with the duration of 300 sec. It is determined that during the street parking design parallel to the sidewalk it is necessary to implement the restriction of the parking duration to increase the road network capacity and traffic flow speed.