Видання НТУ "ХПІ"
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Документ Проблематика забезпечення надійності бічної поверхні поршнів форсованих ДВЗ(Національний технічний університет "Харківський політехнічний інститут", 2024) Марченко, Андрій Петрович; Пильов, Вячеслав ВолодимировичПроаналізовано перспективні напрямки і тенденції розвитку двигунів техніки спеціального призначення. Підвищення літрової потужності двигунів призводить до критичного зростання теплової та механічної напруженості елементів їх конструкцій та відповідного зменшення ресурсу. До найбільш схильних до виходу з ладу деталей форсованих двигунів належать поршні. Серед характерних критичних зон конструкції поршня, в яких спостерігається втрата параметричної і фізичної надійності, виділяють окрему критичну зону на навантаженій та ненавантаженій сторонах спідниці поршня біля пальцевого отвору. Проведено аналіз публікацій і показано, що виникнення явища натирання чи задирання бічної поверхні спідниці поршня, що спостерігається для форсованих конструкцій в означеній зоні, не пояснено вичерпно в існуючій системі наукових поглядів. Prospective directions and trends in the development of special-purpose engines are analyzed. An increase in swept volume power density of engines leads to a critical raise in thermal and mechanical stress in the engine structural elements and to a corresponding reduction in its resource. Pistons are among the elements of boosted engines that are most prone to failure. Among the characteristic critical zones of the piston design, in which losses of parametric and physical reliability were observed, a separate critical zone on the loaded and unloaded side of the piston skirt near the piston pin bores is singled out. An analysis of publications was carried out and it was shown that the occurrence of the phenomenon of wear or seizures of the side surface of the piston skirt, which is observed for the boosted designs in the specified zone, is not explained exhaustively in the existing system of scientific views.Документ Computational studies of electromagnetic field propagation and deforming of structural elements for a thin-walled curved workpiece and an inductor(Національний технічний університет "Харківський політехнічний інститут", 2024) Lavinsky, D. V.; Zaitsev, Yu. I.At the present stage of industrial development, the electromagnetic field is widely used in various technological processes. The force effect of an electromagnetic field on conductive materials is used in a class of technological operations called electromagnetic forming. Problem. Under the conditions of electromagnetic forming, the main element of the technological equipment – the inductor – is simultaneously subjected to the force impact with the workpiece. At certain levels of the electromagnetic field, the deformation of the inductor becomes so significant that it can lead to a loss of its efficiency. Goal. Computational analysis of a thin-walled curved workpiece and a two-turn inductor under the conditions of electromagnetic processing of the workpiece corner zone. Determining the distribution of quantitative characteristics ofthe electromagnetic field and the stress-strain state and conducting assessments based on them regarding the efficiency of the technological operation. Methodology. Computational modeling using the finite element method as a method of numerical analysis. The results on the distribution of quantitative characteristics of the electromagnetic field and components of the stress-strain state for a thin-walled workpiece and an inductor are obtained. It is shown that for the specified characteristics ofthe technological operation, the inductor remains operational, and plastic deformations occur in the workpiece. A series of calculations were carried out, in which some parameters of the technological system were varied. Originality. For the first time, the results of the calculation analysis of the quantitative characteristics distribution of the electromagnetic field of the deformation process for the «inductor – thin-walled curved workpiece» system are presented. Practical value. The presented design scheme of a curved thin-walled workpiece and a twoturn inductor, the method of calculation analysis and some obtained results can be used in the analysis ofelectromagnetic processing of thin-walled structures that contain curved elements.Документ Computational analysis method of the electromagnetic field propagation and deformation of conductive bodies(Національний технічний університет "Харківський політехнічний інститут", 2023) Lavinsky, D. V.; Zaitsev, Yu. I.The electromagnetic field is an integral attribute of the operation of many technical and technological systems. The action of an electromagnetic field leads to deformation, a change in temperature, a change in the physical properties of the materials. Problem. High-intensity electromagnetic fields can cause such a strong deformation of conductive bodies that it can lead to irreversible shape change or destruction. This fact is used in a class of technological operations: electromagnetic forming. Here, both the workpiece and the equipment are subjected to intense force action. As a result, equipment elements may become inoperable. Goal. Creation of a computational analysis method of the electromagnetic field propagation in systems of conductive bodies and subsequent analysis of deformation. Application of this method to the study of processes in electromagnetic forming systems in order to determine rational operational parameters that provide the result of a technological operation. Methodology. A variational formulation of the problems of an electromagnetic field propagation and deformation of conductive bodies systems is used. Numerical modeling and analysis are performed using the finite element method. Results. In a general form, a system of resolving equations for the values of the vector magnetic potential and displacements is obtained. The influence of the electromagnetic field is taken into account by introducing electromagnetic forces. The results of calculations for a technological system designed for electromagnetic forming of curved thinwalled workpieces are presented. Originality. For the first time, a method of computational analysis is presented, which involves modeling within the framework of one design scheme both the process of electromagnetic field propagation and the process of deformation. Practical significance. The proposed method of computational analysis can be used for various technological systems of electromagnetic forming in order to determine the rational parameters that ensure both the operability of the equipment and the purpose of the technological operation - the necessary shaping of the workpiece.