Збірники наукових праць ЦНТУ
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Item type:Item, Чисельне моделювання пружного гістерезису сипкого матеріалу(ЦНТУ, 2023) Івлєв, В. В.; Ivliev, V.В результаті чисельного моделювання процесу деформації сипкого матеріалу (на прикладі зернового матеріалу) отримані рівняння регресії другого порядку залежностей площі петлі пружного гістерезису і максимального значення сили при 25 % відносній деформації зернового матеріалу від його фізико-механічних властивостей (щільність, коефіцієнт Пуассона і модуль Юнга). Представлені результати можуть бути використані при подальшому моделюванні або при створені фізико-математичних моделей процесу стискання зернового матеріалу в грануляторах, екструдерах та експандерах. The elastic hysteresis of bulk material is an important problem in many fields of science and technology, including mining and metallurgy, construction, energy, and engineering. This is due to the fact that loose materials consist of a large number of particles that can shift relative to each other under the influence of external loads. This process is accompanied by energy losses and changes in the shape of the material structure, which in turn leads to elastic hysteresis. Knowledge of material behavior under various loading conditions is essential for developing safe and effective engineering solutions. The purpose of the research is to determine the parameters of the deformation of loose material (for example, granular material) depending on its physical and mechanical properties in the Simcenter STAR-CCM+ software package. The elastic hysteresis loop reflects the behavior of the material under cyclic loading, when strain and stress changes occur. Loop area is a measure of material energy losses that occur during cyclic loading. As a result of numerical modeling of the process of deformation of loose material (on the example of granular material), the regression equations of the second order of the dependences of the area of the elastic hysteresis loop and the maximum force value at 25% relative deformation of the granular material from its physical and mechanical properties (density, Poisson's ratio and Young's modulus) were obtained. The presented results can be used in further modeling or in the creation of physico-mathematical models of the process of compression of grain material in granulators, extruders and expanders.Item type:Item, Комп’ютерне моделювання процесу прямого пресування через різні профілі матричних лійок(ЦНТУ, 2020) Свяцький, В. В.; Скрипник, О. В.; Конончук, С. В.; Sviatskyi, V.; Skrypnyk, O.; Kononchuk, S.; Свяцкий, В. В.Виходячи з аналізу напруженого і деформованого стану стадії пресування, що встановилася, запропоновано використовувати профіль матричної лійки, виконаний по лінії ковзання, що розділяє пружну і пластичну зону. Результати теоретичних досліджень, комп’ютерного моделювання процесу прямого пресування за допомогою програмного комплексу Deform 2D/3D, експериментальних дослідів показали, що кращі умови пресування досягаються через матрицю із профілем, який виконаний по лінії ковзання. The stressed and deformed state of the metal and the dimensions of the center of deformation during pressing depend significantly on the design of the tool and, in particular, on the shape of the matrix funnel. However, there is still no single point of view on the influence of the geometry of the deformation center on the energy forces of the metal pressing process. Based on the analysis of the field of slip lines of the steady-state stage of pressing through a symmetric single-point matrix, it is proposed to use the profile of the matrix funnel made along the slip line separating the elastic and plastic zones. The following types of matrix funnel profiles were investigated using computer simulation of direct extrusion of lead samples with a drawing value 81 at a speed of 1 mm/s: cycloid concave; convex; the second convex, which is built on the logarithmic dependence; conical and concave, which is built along a sliding line that separates the elastic zones from the plastic in the pressing process. The results of theoretical studies, computer simulations of the direct pressing process using the Deform 2D/3D software package, and experimental experiments have shown that optimal energy-power conditions are achieved by pressing through a matrix that has a profile made along the slip line. The results of the experimental study of the kinetics of the flow of the discrete medium showed that the shape of the matrix funnel influences the size of the deformation center and the distribution of the resulting deformation in the molding. From the analysis of deformation of the granules, it is determined that the concave funnel, built along the slip line, is characterized by a curvature of the axisymmetric particles in the direction of deformation. These curvatures decrease as the granules move to the axis of symmetry of the matrix. It is noted that for a convex funnel, the length of the deformation center is greatest; for a conical metal flow is close to the radial in the direction of the truncated cones. На основе анализа поля линий скольжения установившейся стадии прессования через симметричную одноочковую матрицу предложено использовать профиль матричной воронки, выполненный по линии скольжения, разделяющий упругую и пластическую зону. Результаты теоретических исследований, компьютерного моделирования процесса прямого прессования с помощью программного комплекса Deform 2D/3D, экспериментальных опытов показали, что оптимальные энергосиловые условия достигаются при прессовании через матрицу, которая имеет профиль, выполненный по линии скольжения.Item type:Item, До визначення швидкості ковзання та зусилль, які діють в зачепленні черв’ячної передачі(ЦНТУ, 2017) Невдаха, Ю. А.; Дубовик, В. О.; Невдаха, А. Ю.; Пукалов, В. В.; Nevdaha, Y.; Dubovik, V.; Nevdaha, А.; Pukalov, V.В статті розглянута величина швидкості ковзання і її напрям відносно лінії дотикання черв’яка і черв’ячного колеса, визначені швидкості ковзання та зусилля, які діють в зачепленні. The purpose of the article is to investigate ways to increase the durability and tractive ability of worm gears. Improve the durability of worm gears by improving the working environment, as well as by applying an oil wedge. One of the ways to increase the pressure in the oil wedge, as well as increasing the loading capacity of the transmission is to change the geometry of the clutch. The article considers the value of the slip speed and its direction relative to the line of contact of the worm and worm wheel. The sliding speeds and forces that are in contact are determined. The peculiarity of a worm gear is slipping along the teeth. The magnitude of the slip velocity and its direction relative to the line of contact between the two bodies moving relative to each other, as well as the shape of the tangential surfaces, largely determine the hydrodynamic conditions of the engagement and, consequently, affect the performance of the transmission. Investigating the speed of sliding in worm gears it was found that the speed of movement of the contact line relative to the tooth of the worm wheel was small compared with the speed of the worm worm. The values of the angles formed by contact lines with directions for different points of the worm vary in a wide range. It was established that conditions for the formation of an oil wedge deteriorate with a decrease in the angle of recovery of a worm turn.Item type:Item, Дослідження складових опору ґрунту при роботі щіткових пристроїв(ЦНТУ, 2017) Войтік, А. В.; Головатюк, А. А.; Гнатюк, М. Г.; Voytik, А.; Golovatyuk, А.; Gnatyuk, M.В статті розглянуто силову взаємодію прутка ворсу циліндричної щітки з ґрунтом в процесі видалення останнього з валків, що вкривають кореневу систему маточних рослин. Встановлено, що на енергоємність процесу будуть впливати сили в’язкості ґрунту, статичного опору його частинок та опору на відкидання ґрунту з валка. Також на опір впливають сили, що викликані переміщенням ущільненого ядра та сили тертя призми волочіння по поверхні прутка та ґрунтового валка. The article is devoted to the problem of the disclosure of the root system of mother plants with brush working parts. When working brushes on their pile rods there are resistance forces that require certain energy costs. By selecting rational kinematic parameters, it is possible to minimize energy costs for work. In this work the position of the pile rod in the working phase is analyzed and the forces acting on it are determined. The main resistance force is directed opposite to the absolute velocity vector and includes three components. Firstly, these forces of resistance are caused by the viscosity of the soil, taking into account its plasticity and deformation. The force of the static resistor of the displacement of particles takes into account the properties of the soil as a friable medium simultaneously with plastic properties. Also, the force to reject soil particles is determined. It has been established that in addition to these forces, resistance is caused by the displacement of the core of the seal under the working rod and the frictional forces when driving the prisms of drawing on the surfaces of both the rod itself and the ground roll. The dependence of the resistance strength on the movement of the rod in the soil from the basic parameters of the brush has been determined, and it has been shown that there is a minimum of function within the limits of the change in the velocity of the pile rods from 3 to 6 m / s, when the force takes the minimum values up to 0.3 N per rod.