Кафедра прикладної механіки та мехатроніки
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Item type:Наукова стаття, Mathematical Modeling of a Small-Dimension Hydropulse Vibrator with a Valve-Driven Pressure Pulse Generator(2026-04-01) Povstyanoy, Oleksandr; Obertyukh, Roman; Slabkyi, AndryiThe article presents research on a new compact vibrator design based on a hydraulic pulse drive with a built-in valve-type pressure pulse generator. Based on scientific assumptions, an approximate cycle diagram of the working cycle, a structural diagram of the vibrator, and a representation of the hydraulic link of its hydraulic system as a Kelvin–Voigt model were developed. A dynamic model of the vibrator was designed, in which the hydraulic link interacts with the moving links via transmission ratios. Based on simplified dynamic models of the forward and reverse strokes of the executive element, a mathematical model of the vibrator was developed using the d’Alembert principle, resulting in a system of 2nd-order differential equations describing the motion of the executive element’s mass during its forward and reverse strokes. Consumption for energy equations at time intervals was also considered according to the approximate cycle diagram of the vibrator’s working cycle and the conditions of uniqueness that limit the movement of the mass of the executive element and the deformation of the hydraulic link. To provide a detailed analysis of the developed mathematical model, Python program code was written. The workflow was visualized in Google Colab. It was confirmed that the operating frequency range of a hydraulic pulse vibrator of this design is not a single fixed number – it is parametric and depends on the settings of the hydraulic system. By adjusting the pumping station parameters and the stiffness of the vibrator’s elastic elements, it is possible to achieve an actuator frequency up to 150 Hz and an amplitude of up to 2 mm.Item type:Наукова стаття, An impact of technological factors on the kinematic accuracy of cylindrical gear wheels during machining(Sumy State University (ROR), 2025-03-03) Povstyanoy, Oleksandr; Halchuk, Tetyana; Bembenek, Mihal; Valetskyi, BohdanThe work analyzes the means of controlling the accuracy of gears from the point of view of ensuring the manufacture of parts of a given quality. A theoretical study of the influence of the geometry and accuracy of the elements of the technological system and the process of gear milling with a worm cutter on the kinematic accuracy of cylindrical gears has been carried out. A method of conducting experimental studies of the wheel on the kinematic accuracy has been selected, which consists in comparing the circular distances between the same profiles of two teeth of the wheel with similar distances between the profiles of the other two teeth of the same wheel. The influence of the technological modes of processing of the gear milling process on its accuracy indicators has been experimentally studied. An optimization model for selecting technological modes of processing has been developed in order to ensure the required kinematic accuracy of the gear after the gear milling operation with a worm cutter due to the error of the accumulated step, as well as to reduce the number of experiments. The work was carried out using data from a private complex study of the elementary indicator of kinematic accuracy of the accumulated error of the wheel pitch, obtained during measurement control. During the work, metrological means and methods of gear wheel control were used. The research results were processed by methods of mathematical statistics.Item type:Наукова стаття, Evaluation of the surface characteristics of VT8 titanium alloy bio-functionalized through plasma electrolytic oxidation(2024-03-15) Povstyanoy, Oleksandr; Imbirovych, Nataliia; Zvirko, OlhaTitanium and its alloys are considered promising materials in the medical field due to a number of mechanical and corrosion properties, as well as biocompatibility. In order to improve the operational properties of such alloys, their surface is modified by various methods, particularly plasma-electrolytic oxidation (PEO). The main feature of the PEO method is the wide possibility of controlling the physical and mechanical properties of coatings by changing the electrolyte composition and operating modes. These include hardness as one of the important functional properties of oxide-ceramic biocompatible coatings which can be changed in a wide range. The hardness should be controlled to avoid brittle fracture of coatings. In this work, a number of PEO regimes were developed by varying the electrolyte composition, the ratio of anodic to cathodic currents, and the treatment duration. Coatings with a hardness in the range of 1400–2500 MPa and a thickness of 3.4–12 μm were synthesized. An acceptable correlation between the hardness and thickness of the coating was revealed. It enables the assessment of coating thickness by measurements of hardness and can be used for non-destructive evaluation of coating thickness.Item type:Наукова стаття, Automation of Optimization Synthesis for Modular Technological Equipment(Sumy State University, 2023-05-22) Povstyanoy, Oleksandr; Zaleta, Olha; Redko, RostyslavTechnological equipment design based on functionally modular methods is widely used in various technical fields. The designed object can be a technological machine, a production line, or a manufacturing complex. Special attention is paid to the optimization of its structure. The sequence of performing all stages of the optimization synthesis problem is presented in the article. To find a solution to this task, the developer should apply the complete or directed search of acceptable structure options and determine the best one using some optimization criteria to evaluate their quality. It can be simple enough if the designed technical system structure consists of no more than several elements. For example, if the number of alternative elements options is several dozen, it takes much time to accomplish the search correctly. Thus, the greater the number of components considered, the more difficult it is to do all the necessary calculations manually. In this case, machine resources should be involved. This scientific work aims to identify procedures of optimization synthesis that can be automated. Also, appropriate software has to be developed. Our computer program is based on the algorithm of a complete search of all options of the technical system structure. It can process an extensive array of input data and produce all possible and logically permissible results in the form the designer can analyze using the Pareto method to choose the best one. This software can be used for any technical system with a modular structureItem type:Наукова стаття, Impact of Technological System’s Characteristics on the Machining Accuracy of Bearing Rings(Sumy State University, 2023-11-10) Povstyanoy, Oleksandr; Halchuk, Tetyana; Redko, Rostyslav; Polinkevych, RomanThe article shows the influence of the technological system of an automated lathe, in particular cam chucks, on the accuracy of machining bearing rings for production conditions. The value of the deformation during machining, i.e., the non-circularity of the ring of a single row tapered roller bearing 32017X in outer diameter, was investigated. For the study, samples were selected that were processed under the same conditions directly in the production unit of PJSC “SKF Ukraine” without interference with the technological process. The use of replaceable floating cams in the chuck design was proposed to increase the accuracy and productivity of machining. Experimental studies have shown that the machined surface’s ovality depends on the chuck cams’ clamping force. The effectiveness of computer processing of statistical data on the accuracy control of engineering products was shown. Implementing machining accuracy control in production using the Minitab computer program was presented. It was proven that the quality of products is formed under the influence of the use of modern computer technologies at all stages of manufacturing and control of parts, which ensures research in a wide range of changes in technological parameters and comparison of individual studies with actual machining conditions on the machine, with the results of a sufficient level of reliability.