Browsing by Author "Posmitiukha, Oleksandr P."
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Item Analytical Determination of the Reduced Rotational Resistance Coefficient of the Construction Machine Slewing Gear(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2019) Bondarenko, Leonid N.; Posmitiukha, Oleksandr P.; Hlavatskyi, Kazymyr Ts.EN: Purpose. Designing new models of construction machines is closely related to the development of slewing gear, and that, in turn, has a drive whose power and dimensions depend on the rotational resistance and the reduced fric-tion coefficient in the units. The absence of analytical dependencies for determining the reduced coefficient of friction for the rotation of construction machines, first, restricts the designer's ability to select materials, and secondly, does not allow the adoption of optimal design solutions. Therefore, the purpose of the article is to find analytical solutions to determine the rotational resistance in the slewing gear of construction machines, which allows project-ing more advanced gears and machines in general. Existing techniques are based on empirical dependencies and experimental coefficients that reduce the accuracy of calculations, increase the size and cost of work. It is proposed to improve the accuracy and simplify the process of determining the rotational resistance and the magnitude of the reduced rotational resistance coefficient of the building tower cranes. Methodology. The set objectives can be achieved by means of analytical dependencies for determination of rolling friction coefficients over linear and point contacts. This will enable to find the more accurate value of the resistance coefficient, and the constructor during the calculations to take targeted measures to reduce it, using the mechanical constants of materials of the units and their geometric parameters. The calculation is based on Hertz contact deformation theory and the body point plane mo-tion theory. Findings. The obtained dependencies will allow analytically to find the resistance of rolling resistance of rollers in construction machines with fixed and rotating pillars, with circular rotary devices, as well as in ball and roller slewing rings. The calculated values of the rotational resistance coefficients for some types of mechanisms give similar values with those recommended, while for others they significantly differ and require their refinement in reference values. Originality of the work consists in the use of analytical dependences for determining the reduced coefficient of the rotational resistance over linear and point contacts using Hertz contact deformation theory and Tabor partial analytic dependencies theory. Practical value. The obtained dependencies will allow to design new types of slewing gear units of the construction machines and to reveal the additional rotational resistances.Item Analytical Method of Determining the Movement Resistance of a Tip for Forming Rectangular Technological Hole in the Lower Structure Tracks(IOP Publishing, 2020) Posmitiukha, Oleksandr P.; Hlavatskyi, Kazymyr Ts.; Kravets, Svyatoslav V.; Suponyev, Volodymyr; Koval, AndreyEN: Abstract. The aim of this work is to theoretically determine the total resistance to soil pricking with a wedge-shaped tip to create a rectangular cavity and to determine the influence of the size of the working equipment and soil environment in the repair of earthenware or areas where trench technology can-not be used. To determine the forces of the recess of the replaceable pilot, the law of change of soil pressure on the working surfaces of the working equipment was first determined, which is based on the idea of the change of the soil elastic state at its compaction was determined, which is determined by the compression module of deformation of the soil. The processes occurring during the formation of wells and new approaches to the improvement of calculations have been described. On the basis of the pro-posed model of the piercing process, the laws of change of the normal pressure of soil resistance on the surface of the wedge working equipment are established. Based on its value, the results of theoretical studies have received a rational form and parameters of the tip of the work equipment.Item Determination of Equivalent and Optimal Sizes of Wedge Tip from Flange for the Static Perforation of Soil(Український державний університет залізничного транспорту, Харків, 2018) Posmitiukha, Oleksandr P.; Kravets, Svyatoslav V.; Suponyev, Volodymyr; Glavatsky, Kazimir Ts.EN: Abstract. The purpose of the study is to create a new design of the working tip for the perforation of the soil when laying two or more buildings trenchless way and determine its rational parameters. Method. It is known that for static perforation in the formation of cavities in the soil for communication is traditionally used cone-shaped working elements, which is the most common, cheap and reliable. However, the study revealed inefficiency. The design of the working elements of the soil perforation for trenchless laying of two or more buildings simultaneously in the form of a tip, which consists of a wedge-shaped part and a control part in the form of a rectangle with half-cylinders. The basic principles and mathematical dependences of determining the size of the working body are described. Scientific novelty. Regularities of changes in soil pressure on the lateral, conical and wedge surface, flat and cylindrical part of the tip, allowed to obtain an analytical dependence for the calculation of the resistance force depending on the physical and mechanical properties of the soil, the diameter and the number of cases established simultaneously. Also, when comparing the cone-cylindrical and flat tips, it can be argued that the breakdown force of the flat tip decreases from 1.2 to 1.7 times.Item Substantiation of the Parameters of the Bench for Testing of Railway Wheels for Contact and Fatigue Strength(Technologija, Kaunas, 2022) Raksha, Serhii V.; Anofriev, Pavlo G.; Kuropiatnyk, Oleksii S.; Glavatskij, Kazimir Ts.; Bohomaz, Volodymyr M.; Posmitiukha, Oleksandr P.; Volkova, Svetlana A.ENG: Strength indicators are important parameters of the railway wheels, as they determine the allowable service life of both the wheel itself and the wheelset as a whole. Therefore, the development of bench equipment that allows in the laboratory to reproduce or simulate the real conditions of the wheel load in order to conduct strength tests, is an urgent scientific and practical task. The purpose of this work is to substantiate the parameters of the bench for testing railway wheels for fatigue and contact strength. As the bench has to test railway wheels for fatigue and contact strength at the same time, the requirements of various normative and methodological documents, which determine the procedure for conducting such tests on separate benches, were combined when determining the parameters of the bench. We determined that the working force of the bench should vary from 10% to 100% of the wheel endurance limit, the duration of the tests should correspond to five million load cycles with a frequency of 5 to 10 Hz. To reduce the duration of the tests, pushing on the wheel was carried out by several rollers, which were evenly distributed around the wheel. For the proposed bench, we obtained the dependence that connects the parameters of the test wheel, the parameters of the bench, the wheel pair axle load and the wheel material endurance limit. The results of this study can be used as a basis for the development of new schemes of benches for railway wheels tests.Item Technical Solutions for Working Elements of Machines for Efficient Compaction of Soil(Український державний університет залізничного транспорту, Харків, 2018) Glavatsky, Kazimir Ts.; Cherkudinov, Volodymyr E.; Posmitiukha, Oleksandr P.EN: Abstract. The modernization of machines for compaction of soil on a modular basis has the following advantages: some of their structural elements (working equipment and working elements) can be performed as unified modular units, from which, depending on the technological requirements, it is possible to assemble the required configuration of the sealing machine; the initial state of the machine does not deteriorate, to which it is easy to return; the nomenclature of structural elements and machines in general decreases, as the machine can be completed with variable modules, which leads to an improvement in their quality. When consolidating the soil massive use static, dynamic and combined action on the soil in the form of rollers, vibro-and ramboards. Machines of the boottype are classified into light, medium and heavy, which determines the order of its application. It is obvious that the reduction of technology for the process of soil compaction is possible due to the creation of machines that can change the intensity of the impact on the soil in a wide range.Item Technology of Soil Compaction of the Base of the Track with Vibrating Static Machines of Blocking Action(IOP Publishing, 2020) Hlavatskyi, Kazymyr Ts.; Cherkudinov, Volodymyr E.; Posmitiukha, Oleksandr P.EN: The directions of combination of working bodies in the existing soil compactors and machines of the new generation and the technologies of their application for productive and effective soil compaction of the lower track structure, soil structures of roads and other construction objects are given. The basis of the research is the principle of accelerated soil compaction due to the creation on the surface of the contact with the working bodies of the sealing machines pressure, which exceeds the limit of plasticity of the soil and at the same time limiting the slipping of the sides from under the working sealing surface. It is proposed that the working sealing surface modular type that can change its profile depending on the technological requirements. Further research is aimed at creating the required profile of the working body based on the desired compaction core and the structural formula of the working body of the soil compactor. In this case, replacing the elements in the working bodies with the corresponding mathematical models, we obtain a common mathematical model of the working body of the soil compactor, as well as the profile of its working body, based on the specified energy consumption and technological requirements.