Статті КРС (ЛІ)
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Browsing Статті КРС (ЛІ) by Author "Bal, Olena M."
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Item Development of a Promising System for Diagnosing the Frogs of Railroad Switches Using the Transverse Profile Measurement Method(PC "Technology Center", Ukrainian State University of Railway Transport, Kharkov, 2018) Kovalchuk, Vitalii V.; Sysyn, Mykola P.; Hnativ, Yuriy M.; Bal, Olena M.; Parneta, Bohdan Z.; Pentsak, Andrii Ya.EN: We have developed a system for diagnosing the frogs of railroad switches, based on the application of modern microcontrollers of the type ESP with high technical characteristics and the simultaneous use of the information technology IoT (Internet of Things). The proposed system has advantages over mechanical systems in terms of the accuracy of data, their operational processing and submission to user in order to analyze technical condition of frogs at railroad switches. The results of measuring the transverse profile of frogs at railroad switches make it possible to take scientifically-substantiated decisions regarding the need for recovery repair of frogs by the method of surfacing and for control over gradual decrease in their carrying capacity, for establishing their actual technical condition and residual resource. We carried out experimental-theoretical research into longitudinal profile of frogs at railroad switches laid on the reinforced concrete bars. It was established as a result that after passing 50–65 million tons of cargo (that corresponds to the medium degree of wear) the trajectory takes the shape of a bump. We observe sharp hollows on the reinforced concrete base in the zone where a wheel rolls from a rail wing onto the core, characterized by significant total inclination. Subsequently, when the passed cargo increases, the number of sinusoidal irregularities grows. At wear close to maximal (80–95 million tons passed), the percentage of unfavorable trajectories (sinusoidal and hollows) grows; at low wear, they make up 49.8 %, at a wear of 5−6 mm and larger – 88.3 %. Sometimes there is a transformation of the sinusoidal irregularities into the wave-shaped ones. We have established characteristic motion trajectories of the center of mass of the wheel over the frog depending on the wear of rail wings and the core of a frog and the passed cargo. A mathematical model was constructed for predicting the wear of frog profile depending on the total weight of passed cargo.Item Investigating the Influence of the Diameter of a Fiberglass Pipe on the Deformed State of Railroad Transportation Structure “Embankment-Pipe”(РС Тесhnology Сеntеr, 2022) Kovalchuk, Vitalii V.; Sobolevska, Yuliya; Onyshchenko, Artur; Bal, Olena M.; Kravets, Ivan B.; Pentsak, Andriy; Parneta, Bogdan Z.; Kuzyshyn, Andriy; Boiarko, Vladyslav; Voznyak, Oleh M.ENG: This paper has analyzed the use of fiberglass pipes in the body of the railroad embankment by a method of pushing them through the subgrade. A flat rod model has been improved for assessing the deformed state of the transport structure "embankment-fiberglass pipe" by a method of forces when replacing the cross-section of the pipe with a polygonal one. The analytical model accounts for the interaction between the pipe and soil of the railroad embankment. To this end, radial and tangential elastic ligaments are introduced into the estimation scheme, which make it possible to simulate elastic soil pressure, as well as friction forces that occur when the soil comes into contact with the pipe. The deformed state of the transport structure "embankment-fiberglass pipe" was calculated by the method of forces and by a finite-element method under the action of load from the railroad rolling stock, taking into consideration the different cross-sections of the pipe. It has been established that with an increase in the diameter of the fiberglass pipe, the value of deformations of the subgrade and fiberglass pipe increases. With a pipe diameter of 1.0 m, the deformation value in the vaulted pipe is 2.12 mm, and with a pipe diameter of 3.6 m – 4.16 mm. At the same time, the value of deformations of the subgrade under the sleeper is 5.2 mm and 6.0 mm, respectively. It was determined that the maximum deformations of the subgrade, which occur above the pipe, with a pipe diameter of 3.6 m, are 4.46 mm. At the same time, the maximum vertical deformations of a fiberglass pipe arise in the pipe vault and, with a pipe diameter of 3.6 m, are 4.16 mm. It has been established that the maximum horizontal deformations of the subgrade occur at points of horizontal diameter of the fiberglass pipe while the minimal horizontal deformations of the subgrade occur at points lying on the vertical diameter of the pipe.Item The Study of Strength of Corrugated Metal Structures of Railroad Tracks(НПП ЧП «Технологический Центр», Харків, 2017) Kovalchuk, Vitalii V.; Marcul, Ruslan V.; Bal, Olena M.; Milyanych, Andriy R.; Pentsak, Andrii Ya.; Parneta, Bohdan Z.; Gajda, OleksiyEN: The analysis of the main defects of metal corrugated culverts of the railway, which arise as a result of operation, was conducted, and the problems of providing their durability and strength were highlighted. The problems of adaptation of foreign regulations for designing metal corrugated structures at Ukrainian railways and motor roads were analyzed, the results of experimental and theoretical calculations of bearing capacity of metal corrugated structures were presented. The MCS strength at boundary loading with the railway rolling stock was analyzed by the indicator of influence of corrugation (corrugation dimensions) and the characteristics of soils on their stressed-strained state. Calculation of equivalent forces was performed by the procedure of calculation of railway strength and stability using the finite-element method. The numerical calculation of the stressed-strained state of the MCS was obtained using the licensed software FEMAP with MSC NASTRAN. An analysis of multi-choice calculations of the strength of MCS, made of corrugated structure Multiplate MR150 with thickness of a corrugated sheet of 6 mm, with dimensions of corrugation waves of 150×50 mm, showed that its bearing capacity is provided at degrees of compaction of soil backfill from 0.9 to 1.0. Based on the obtained data, it was found that the direct cause of occurrence of residual deformation of metal corrugated pipe may be an increase in stresses in metal sheets of the pipe up to the values that exceed permissible stresses and as a result of local initiation of a plastic hinge. The condition of initiation of a plastic hinge, which takes place in the MCS arch, holds only if there is adverse simultaneous influence of two factors (causes): letting inequalities develop beyond permissible values without taking measures for its elimination and a decrease in the degree of compaction of backfill soil below 90 % (the second cause). In the absence of one of the causes, a plastic hinge might not emerge. In the joint effect of both causes, the first cause, the impact share of which is 42 %, prevails, whereas the share of the second cause is 22 %. The obtained results of the MCS bearing capacity are needed for optimal MCS designing, establishing causes of defect emergence, timely making relevant engineering decisions in order to increase the MCS bearing capacity and reasonable use of funds for the construction or reconstruction of existing transport facilities with the use of metal corrugated pipes. The results of the study may be used by engineers of Bridge testing stations of Ukrrailway and Ukravtodor and by designing organisations involved in designing metal corrugated structures of large diameters.