Journal of Engineering Sciences / Журнал інженерних наук
Permanent URI for this collectionhttps://devessuir.sumdu.edu.ua/handle/123456789/34326
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Item Formation of bearings parts waviness in centerless mortise grinding on rigid supports(Sumy State University, 2023) Chalyj, V.; Moroz, S.; Tkachuk, A.; Zablotskyi, V.; Trokhymchuk, I.; Stelmakh, A.The formation of waviness on the working surfaces of bearing parts is associated with fluctuations in the size of the cut layer of metal and changes in the components of the cutting force. Laplace operators were used to model the centerless grinding system based on the construction of the transfer function and the characteristic equation. It was found that the formation of waviness depends on the position of the hodograph of the movement of the vector of the center of the part in the complex plane, which in turn depends on the geometric parameters of the rigid supports of the centerless grinder machine. This makes it possible, based on hodographs and the angular orientation of their asymptotes, to determine the geometric stability of the process depending on the angles of adjustment of the rigid supports of the grinder machine. Two methodological approaches were used to confirm the correctness of the hypotheses. The first one is a multiplication of wave’s hodographs. The second one is regeneration displacement and the coincidence of the combined hodograph of regeneration and waviness displacement mechanisms with the hodograph of infinitely rigid machine displacement. The diagrams which allow choosing geometry of adjustment of rigid support that allows to increase or decrease parameters of certain harmonics are developed. The 3D diagram allows setting the local minima, characterized by acceptable geometric adjustment conditions, providing regulated waviness of the working surfaces of bearing parts.Item Simulation of point defects formation in the fuel element of a nuclear power plant’s wave reactor(Sumy State University, 2023) Opyatyuk, V.V.; Kozlov, I.L.; Karchev, K.D.; Vistiak, S.V.; Kozlov, O.I.; Turmanidze, R.This paper considers the point defects that influence the operation of a wav nuclear power reactor with a uranium fuel medium. The formed individual point defects or such defect groups can produce a perturbing effect on the stability of the nuclear reactor operating mode and involve its transition to an unstable state. Studies have been carried out on the effect on the characteristics of the nuclear burnup wave in a medium with neutron multiplication for 2D geometry. For the calculation, the uranium-thorium fissile medium has been considered. The parametric calculations were carried out with 235 U different enrichment percents and different values of neutron activation energy. At that, it was assumed that the wave (flow) reactor stable operation region is located in the range of activation energies from 10–3 eV to 1 eV or in the region from 2 MeV to 8 MeV. When calculating the neutron flux intensity in a wave reactor, the influence of point defects and their aggregates on the decelerating elastically scattered neutrons’ flux density and the flux density of decelerating non-elastically scattered neutrons was considered. The dependences of the point defects formation rate on the medium fissile temperature for several compositions of the uranium-thorium medium are obtained. As visually identified, the graphic materials obtained during the calculations are similar to the photos of fuel rods after the energy campaign.Item Heat exchange in a contact zone of nanoinstrumentation with elements of the microsystem technology(Sumy State University, 2023) Antonyuk, V.S.; Bondarenko, I.Iu.; Vislouh, S.P.; Voloshko, O.V.; Bondarenko, M.O.Theoretical studies of physical processes and phenomena in the zone of physical interaction of nanoinstruments with the surfaces of elements of microsystem technology are carried out in work. Based on the conducted research, mathematical models of energy heat exchange in the zone of physical contact of nanometric dimensions were compiled, and their analytical solution was obtained using the Fourier method of separation of variables and Goodman’s integral method. Simultaneously, the energy components of the processes in the nanocontact zone were considered. The numerical solution of the mathematical model of energy heat exchange in the zone of physical nanocontact was carried out using a software application based on the finite element method. The results were checked according to the equivalent thermal scheme to confirm the adequacy and accuracy of the obtained models. As a result, the mechanisms of energetic interaction of the nanoinstrument with the surfaces of the elements of microsystem technology devices were clarified. It is shown that the use of the proposed method of equivalent thermal circuits for the evaluation of mathematical models of the energy interaction of nanoinstruments with the surfaces of microsystem technology device elements, as well as the further study of the distribution of thermal fields in the nanocontact zone, differs from other numerical and analytical methods in terms of sufficient accuracy and speed of calculations. At the same time, it was established that the discrepancy between the results of mathematical modeling and the results obtained according to the equivalent thermal scheme does not exceed 5-8 %.Item Optimization of graphene oxide’s characteristics with TOPSIS using an automated decision-making process(Sumy State University, 2023) Javanbakht, T.The present study focuses on a new application of TOPSIS to predict and optimize graphene oxide’s characteristics. Although this carbon-based material has been investigated previously, its optimization with this method using an automated decision-making process has not been performed yet. The major problem in the design and analysis of this nanomaterial is the lack of information on comparing its characteristics, which has led to the use of diverse methods that have not been appropriately compared. Moreover, their advantages and inconveniences could be investigated better once this investigation provides information on optimizing its candidates. In the current research work, a novel automated decision-making process was used with the TOPSIS algorithm using the Łukasiewicz disjunction, which helped detect the confusion of properties and determine its impact on the rank of candidates. Several characteristics of graphene oxide, such as its antibiofilm activity, hemocompatibility, activity with ferrous ions in hydrogen peroxide, rheological properties, and the cost of its preparation, have been considered in its analysis with TOPSIS. The results of this study revealed that the consideration of the criteria of this nanomaterial as profit or cost criteria would impact the distances of candidates from the alternatives. Moreover, the ranks of the candidates changed when the rheological properties were considered differently in the data analysis. This investigation can help improve the use of this nanomaterial in academic and industrial investigations.Item Optimization of greenhouse microclimate parameters considering the impact of CO2 and light(Sumy State University, 2023) Соколов, Сергій Вікторович; Соколов, Сергей Викторович; Sokolov, Serhii ViktorovychThe most critical parameters of the microclimate in greenhouses are air and soil temperature, air and soil moisture, plant illumination, and carbon dioxide (CO2) concentration in photosynthesis. New energy sources and resource-efficient management of microclimate parameters in greenhouses can be utilized to reduce greenhouse crop cultivation costs and increase profits. As the plant mass increase depends on photosynthesis, which involves the formation of glucose in the plant chloroplasts from water and carbon dioxide under the influence of light radiation, the saturation of greenhouses with carbon dioxide has become popular in recent decades. However, insufficient light slows down the process of glucose formation, while excessive light intensity negatively affects photosynthesis. Based on the experimentally proven Van Henten model of plant growth and using the MATLAB environment, a methodology was proposed, and the dependence between CO2 concentration and leaf lettuce illumination power required for maximum photosynthesis was determined. It is equal to 0.57 ppm/(W/m2 ). Such dependence should be considered when designing control systems to reduce resource and energy costs for greenhouse crop cultivation while ensuring maximum yield.Item Effects of cryogenically treated CFRP composite on the buckling behavior in the adhesively bonded beam(Sumy State University, 2023) Uysal, M.U.Carbon fiber reinforced plastic (CFRP) composite materials have favorable mechanical and physical properties such as low density, high strength-to-weight ratio, high fatigue resistance and high creep behavior, and high stiffness. Thanks to these unique properties, they produce aircraft parts such as outer flaps, carry-through structures, and center wing boxes and automotive parts such as body panels, engine components, and structure members. However, studies have been continuously performed on improving the properties of CFRP composite materials. Recently, investigation of the effects of cryogenic (LN2) cooling on the mechanical behavior and characteristic of these composite materials is getting a popular and important issue. In this sense, this study aims to examine the buckling behaviors of adhesively bonded beam-produced cryogenically treated carbon fiber reinforced plastic (Cryo-CFRP), CFRP, steel, and aluminum. Therefore, a new finite element model was adopted to evaluate the buckling capacity of Cryo-CFRP composite material in the adhesively bonded beam. The model is a supported adhesive beam subject to two oppositeedge compressions until the material buckles. The elastic, homogeneous adhesive was used in the assembly. Finite element models for the adhesively bonded beam having four different adherents (CRFP, Cryo-CFRP, steel, and aluminum) were established by ANSYS® software. The critical buckling loads of the adhesively bonded beam were predicted, and their mode shapes were presented for the first six modes. The effects of the usage of Cryo-CFRP on the critical buckling load were investigated. Among the adherents’ materials, the highest critical buckling load was determined for Cryo-CFRP/Steel adhesively bonded beam as 23.6 N. This value was obtained as 22.3 N for CFRP/Steel adherent samples. Thus, the critical buckling load was increased by 5.6 % when one adherent steel was constant and the other adherent material changed from CFRP to Cryo-CFRP. Also, the critical buckling load increased by 3.7 % when using a cryogenically treated Cryo-CFRP/Aluminum couple instead of a CFRP/Aluminum couple in the sandwich beam. The findings demonstrated that the cryogenic treatment positively affects the buckling behavior in the adhesively bonded beam.Item Movement monitoring system for a pneumatic muscle actuator(Sumy State University, 2023) Соколов, Олександр Сергійович; Соколов, Александр Сергеевич; Sokolov, Oleksandr Serhiiovych; Hosovsky, A.; Іванов, Віталій Олександрович; Иванов, Виталий Александрович; Ivanov, Vitalii Oleksandrovych; Павленко, Іван Володимирович; Павленко, Иван Владимирович; Pavlenko, Ivan VolodymyrovychRecent advancements in soft pneumatic robot research have demonstrated these robots’ capability to interact with the environment and humans in various ways. Their ability to move over rough terrain and grasp objects of irregular shape, regardless of position, has garnered significant interest in developing new pneumatic soft robots. Integrating industrial design with related technologies holds great promise for the future, potentially bringing about a new lifestyle and revolutionizing the industry. As robots become increasingly practical, there is a growing need for sensitivity, robustness, and efficiency improvements. It is anticipated that the development of these intelligent pneumatic soft robots will play a critical role in serving the needs of society and production shortly. The present article is concerned with developing a system for monitoring a pneumatic robot’s parameters, including a spatial coordinate system. The focus is on utilizing the relationship between the coordinates and pressure to model the movement of the soft robot within the MATLAB simulation environment.Item Information-extreme machine learning of wrist prosthesis control system based on the sparse training matrix(Sumy State University, 2022) Супруненко, Микита Костянтинович; Супруненко, Никита Константинович; Suprunenko, Mykyta Kostiantynovych; Зборщик, Олександр Петрович; Зборщик, Александр Петрович; Zborshchyk, Oleksandr Petrovych; Sokolov, O.The article considers the problem of machine learning of a wrist prosthesis control system with a noninvasive biosignal reading system. The task is solved within the framework of information-extreme intelligent data analysis technology, which is based on maximizing the system’s information productivity in machine learning. The idea of information-extreme machine learning of the control system for recognition of electromyographic biosignals, as in artificial neural networks, consists in adapting the input information description to the maximum total probability of making correct classification decisions. However, unlike neuro-like structures, the proposed method was developed within a functional approach to modeling the cognitive processes of the natural intelligence of forming and making classification decisions. As a result, the proposed method acquires the properties of adaptability to the intersection of classes in the space of recognition features and flexibility when retraining the system due to the recognition class alphabet expansion. In addition, the decision rules constructed within the framework of the geometric approach are practically invariant to the multidimensionality of the space of recognition features. The difference between the developed method and the well-known methods of information-extreme machine learning is the use of a sparse training matrix, which allows for reducing the degree of intersection of recognition classes significantly. The optimization parameter of the input information description, the training dataset, is the quantization level of electromyographic biosignals. As an optimization criterion is considered the modified Kullback information measure. The proposed machine learning algorithm results are shown in the example of recognition of six finger movements and wrist.Item Automated decision-making with TOPSIS for water analysis(Sumy State University, 2022) Javanbakht, T.This paper aims to present a new application of TOPSIS with an automated decision-making process for the analysis of drinking water. For this purpose, the algorithm was modified with a fuzzy disjunction, and the maximal output values were set to one. The properties of drinking water, such as total dissolved solids, hardness, electrical conductivity, and cost, were the criteria analyzed in this study. These criteria were analyzed with unmodified and modified algorithms. Therefore, the modified TOPSIS was also used to optimize the parameters of the candidates. The appearance of the value of 1.0 in the algorithm’s output was due to the confusion of an individual’s categories of drinking water and undrinkable water. The advantage of this investigation was that, for the first time, it allowed automated decision-making to detect the drinking water in different samples and analyze them according to their characteristics. This would be important in developing new technologies for detecting and analyzing drinking water in the environment. The results of this paper can be applied in materials sciences and engineering.Item Numerical simulation of 2-way FSI problem of face packing seal: Impact of parameters change(Sumy State University, 2022) Сапожников, Ярослав Ігоревич; Сапожников, Ярослав Игоревич; Sapozhnykov, Yaroslav Ihorevych; Загорулько, Андрій Васильович; Загорулько, Андрей Васильевич; Zahorulko, Andrii Vasylovych; Peczkis, G.The article is devoted to creating a refined computer model of the face packing seal (FPS) based on the solution of the two-way fluid-structure interaction (2-way FSI) problem. An approach to the average gap was proposed based on the micro-space’s working medium leakage between the friction pair’s roughness elements. Three FPS designs were studied, in which the following operating parameters were alternately changed: inlet pressure, load factor, stuffing box parameters, and friction coefficient. Young’s modulus, Poisson’s ratio, and the thickness of the annular plate at the bottom of the stuffing box were also changed. The model was created considering the actual geometry of the FPS. The shaft rotation was considered by applying the rotation condition on the wall of the fluid model. The calculation was carried out using the ANSYS Multiphysics software. The results of the calculations were presented in the form of graphic dependences with a comparison of the hydrostatic and contact pressure distributions over the friction pair width. The values of the magnitudes of leakage from the changing parameters were presented. Based on the obtained results, an optimal combination of parameters was evaluated for the most efficient design of the FPS.