Перегляд за Автор "Vychavka, A."
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Документ Modeling of contact stresses and evaluation of wear life of a valve mechanism guide with lubricating grooves(Хмельницький національний університет, 2024) Holenko, K.; Vychavka, A.; Dykha, M.; Dytyniuk, V.Valve guides are crucial for maintaining proper alignment, positioning, and valve stem clearance as it moves in the cylinder head. Valve bushings are subjected to load and sliding friction; with excessive wear of the guides, the engine begins to consume oil and the valve mechanism becomes noisy. This paper proposes the use of a special knurling to restore and increase the wear resistance of guide bushings. The profile tool is designed to restore valve guides by rolling a spiral groove on the inner surface of the sleeve. After applying this technology, a spiral oil-retaining profile remains on the surface of the sleeve bore. . Using the Solid model, the effect of changing the geometry of the guide bore by the lubricating grooves on the maximum and average stress indices in the guide-valve contact was analyzed. It was found that the maximum stresses of the model with grooves are lower than those of the model with a smooth guide surface. Based on the finite element model, the durability of the valve-guide pair with oil-retaining grooves was analyzed and it was determined how many cycles the contact surface of the guide can withstand. It was established that by reducing the contact pressure, the actual resource of the guide with grooves increased.Документ Optimization of technological parameters at discrete strengthening of steel cylindrical surfaces(Хмельницький національний університет, 2024) Dykha, O.; Dytyniuk, V.; Hrypynska, N.; Vychavka, A.The technologies of continuous strengthening of technological surfaces have practically exhausted their capabilities, which calls for the creation of fundamentally new approaches. The application of the principles of discrete-oriented strengthening of tribosystems has wide prospects for improving existing methods of strengthening due to the selection of modes and control of the geometric structure of the surface layer. The essence of the discrete-oriented strengthening method is the application of combined electromechanical processing and electrocontact cementation of cylindrical surfaces. The purpose of the work is to determine the parameters of discrete processing of cylindrical steel parts that are optimal according to the surface hardness criterion. Using the Statistica program, a factorial experiment was implemented according to the Box-Behnken plan, and the results of dispersion and regression analysis of the influence of processing parameters on microhardness were obtained. It was established that the following optimal parameters of DOZ processing are necessary to achieve the maximum values of microhardness (5950 MPa): current strength-500A, force-350 N, contact time-0.3 s.Документ Tribo-acoustic analysis of the processes of dynamic friction(Люблінський політехнічний інститут, 2017) Dykha, A.; Zaspa, Y.; Vychavka, A.The experimental results of the tribo-acoustic control in the integrity of real time of nominally stationary friction joints under conditions of fretting are presented. Violation of the integrity due to the wear of tribofrictions are securely fixed both by the general change in the acoustogram shape of the operating noise, and by the spectrum of noise – the emergence of strong mid-range modes of the contact gap. The emergence of two oppositely directed wave energy cascades in the fretting regimes has been noted: a direct cascade from the mod pumping in the direction of high frequencies and the reverse – toward the low infrasonic frequencies. The first one is related to microplastic deformations in the zones of actual contact, the second one is related to dynamic pointing the slow angular motions in the system of friction. For research, the installation for testing the fretting, which doesn’t contain rotating elements, creating high level of con-tact noise was used. It is shown that the use of a pub-licly available sound recording equipment and standard computer software allows to carry out (for low noise experimental units) contactless acoustic control of the integrity of nominally stationary friction joints under conditions of fretting. Established that low frequency auto-modulation of the friction process, which is mani-fested in the spectrum of the acoustic emission is a consequence of the dynamic targeting slow angular motion in the system of friction.Документ Розрахункова оцінка зносостійкості матеріалів напрямних ковзання(Луцький національний технічний університет, 2017) Диха, О.В.; Посонський, С.Ф.; Маковкін, О.М.; Вичавка, А.А.; Dykha, O.; Posonsky, S.; Makovkin, O.; Vychavka, A.Запропоновано розрахункові залежності для визначення кінетики зміни трибоконтакних параметрів в процесі зношування для мастильного профілю змінної глибини. Проведений розв`язок зносоконтактної задачі для плоских напрямних ковзання. За базову модель зношування прийнята лінійна залежність від безрозмірних комплексів контактного тиску і швидкості ковзання. Отримана формула для розрахунку зносу напрямних ковзання в залежності від шляху тертя.