Центральноукраїнський науковий вісник. Технічні науки. Випуск 7. Частина 2. - 2023
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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 Аналіз науково-технічних інновацій в галузі машинобудування з виявленням закономірності впливу технологічних параметрів(ЦНТУ, 2023) Гайкова, Т. В.; Ковальчук, Д. М.; Гайков, Р. М.; Haikova, T.; Kovalchuk, D.; Haikov, R.У статті розглянуто виявлення закономірності впливу технологічних параметрів на неоднорідність інтенсивності деформації та опору матеріалу пластичному деформуванню у стінці деталі при витяжці прямокутних деталей із біметалів. При розробці технологічного процесу отримання виробів з шаруватих металів з попереднім зчепленням шарів необхідно враховувати пошарові деформації, їх залежності від параметрів процесів формозміни, їх механічні властивості, а також вплив термомеханічних параметрів обробки на міцність з’єднання складових. Based on the analysis of scientific and technical information, it established that today layered metals are one of the most modern and promising materials used in all branches of mechanical engineering and national economy. The use of bimetals allows you to achieve significant cost savings, obtain materials with unique properties, increase production efficiency and competitiveness of a wide class of parts and equipment. The purpose of the article is to analyze the methods of determining the stress state of a workpiece with heterogeneous mechanical characteristics in the process of plastic deformation and to determine the stress-strain state when drawing rectangular parts from bimetals. As a result, of unequal deformation conditions in different parts of the contour, as well as anisotropy of the mechanical properties of the workpiece material, the height of box-shaped parts is even more uneven than the height of axisymmetric parts obtained by drawing. Therefore, in the manufacturing process of such parts, cutting of the uneven edge provided. The trimming allowance depends on the relative height of the part. The bigger it is, the bigger the allowance. Since the flange naturally thickens during drawing in the corner sections of the part contour, this phenomenon taken into account when determining the gap between the punch and the die of the drawing die: in the corner sections, the gap should be greater than in the straight sections of the die contour. Extrusion of box-shaped parts from bimetals causes even greater unevenness of deformations. A different amount of deformation of the layers of the bimetallic work piece imposed on the general sign change of the voltages, which causes bending and warping of the rectilinear parts of the semi-finished product, and therefore, the impossibility of obtaining a high-quality product. Based on the analysis of the stress-strain state of the workpiece in the process of drawing bimetal. The following provisions are proposed: if the mechanical properties of the metal layers do not differ - the two-layer metal behaves like a single-layer, then the ratio of the thicknesses of the two-layer metal does not change after drawing; if the mechanical properties of the layers differ, then the ratio of the thicknesses of the two-layer metal changes after drawing. Thus, when the ratio σs1/σs2 decreases, the thickness of the first layer, which has lower mechanical properties, decreases at the output; the thickness ratio after drawing also depends on the initial ratio of metal thicknesses. Based on the analysis of the stress-strain state of the work piece during the extraction of box parts, the following methods and techniques have been determined for obtaining high-quality parts by extraction and saving material: use metals with similar mechanical properties; the desire to increase the curvature of the corner zones of the work piece; to calculate the dimensions of the work piece for the hood with the involvement of modern mathematical apparatus (potential method); use brake media instead of brake ribs; affect the center of deformation, increasing the effect of unloading tangential stresses.