Journal of Engineering Sciences / Журнал інженерних наук
Permanent URI for this collectionhttps://devessuir.sumdu.edu.ua/handle/123456789/34326
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Item The stress state of a thick-walled hydraulic press cylinder with concentrators(Sumy State University, 2023) Lymarenko, A.; Kurgan, V.; Bazhanova, A.; Khamray, V.; Ponomarenko, A.; Karabegović, I.The article deals with modeling and calculations of volumetric machine-building structures with complex geometry. The relevance of the work lies in the fact that its methodology and results can help design massive structural elements complex in shape, including cylinders of powerful hydraulic presses. Attention is paid to the problems of reducing the metal content of machine-building products and the safe conditions of their operation. Theoretical and applied work is based on numerical methods using analytical solutions to assess the reliability of computer calculation results. The choice of research method is because analytical solutions for massive parts of such a configuration are too complex for numerical implementation. Experimental methods are too expensive and not so universal as to sort out possible variants of shapes and sizes. For the actual model of the press, the capabilities of the finite element method implemented in the ANSYS multipurpose complex were selected and rationally used. The results of the calculations are summarized in the table and shown on the graphs of the stress distribution. Based on the performed calculations (with a reliability check based on the formulas of the theory of elasticity for simplified calculation schemes), conclusions were made to ensure a more even distribution of stresses and a reduction in the metal content of the product.Item Rotor dynamics of turbocompressor based on the finite element analysis and parameter identification approach(Sumy State University, 2022) Вербовий, Антон Євгенович; Вербовой, Антон Евгеньевич; Verbovyi, Anton Yevhenovych; Хоменко, Владислав Володимирович; Хоменко, Владислав Владимирович; Khomenko, Vladyslav Volodymyrovych; Neamtu, C.; Pavlenko, V.; Симоновський, Віталій Іович; Симоновский, Виталий Иович; Symonovskyi, Vitalii Iovych; Павленко, Іван Володимирович; Павленко, Иван Владимирович; Pavlenko, Ivan VolodymyrovychThe article is devoted to improving methods for designing a finite element model of rotor dynamics. For this purpose, numerical implementation of the authors’ computer program “Critical frequencies of the rotor” was developed based on the computer algebra system MathCAD. As a result of the scientific work, a refined mathematical model of rotor dynamics using finite beam elements was created. This model considers the dependence of the radial stiffness characteristics of the bearing supports on the values of the critical frequencies. The reliability of the mathematical model was justified by the permissible differences of the obtained results within 2% compared with the results of finite element analysis using the ANSYS software. The theorem was also proven by the mutual location of the spectra of the natural and critical frequencies. Overall, the proposed scientific approach reduces preparation and machine time compared to numerical modeling using the ANSYS software without losing the accuracy of the calculations.Item Mechanical behaviors of hybrid composites reinforced with epoxy resin(Sumy State University, 2021) Harikrishna, V.; Kumar, K.V.Natural fibres have emerged as a renewable and cheaper substitute to synthetic materials such as glass and carbon. A composite material can be defined as combining two or more materials that result in better properties. The constituents are reinforcement, and the other is a matrix. The main advantages of composites are high strength, stiffness combined with low density. As natural fibres are gaining more importance in recent times, many industries are focusing on these natural fibre composites, so that is why they are used as a component in composite materials. In this experiment, the analysis aims to characterize different natural fibres when combined with different ratios of the coconut coir and the bamboo. So, to fabricate the specimen, the hand lay-up method is used. The coconut coir and the bamboo composition are considered in three different variations. Then the natural fibres are subjected to resin and hardener compositions to test the suitability, tensile strength, flexural strength, and shore hardness test. We also conduct static analysis through ANSYS software.