Browsing by Author "Boiarko, Vladyslav"
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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 Mathematical Мodeling of the Second Stage of Spring Suspension of High-Speed Rolling Stock(American Institute of Physics, AIP Conference Proceedings, 2023) Kuzyshyn, Andriy; Sobolevska, Julia H.; Kostritsa, Sergei A.; Batig, Andriy V.; Boiarko, VladyslavENG: The authors of the article used a thermodynamic model of an air spring with an additional reservoir to simulate the second stage of spring suspension of high-speed rolling stock. In this model, the pressure in the air spring was determined by the differential form of the ideal gas equation of state. Since the air spring is connected to an additional reservoir by means of a pipeline, the equation took into account the change in air mass due to its overflow. When determining the mass flow rate, the flow was considered turbulent, which provided for finding the appropriate Reynolds number and head losses, which consisted of three components: friction, compression and expansion losses. The law of conservation of energy was considered taking into account the heat transfer between the air spring and the environment, as well as the transfer of energy between the air spring and the auxiliary reservoir. Using a simplified mechanical model of high-speed rolling stock, the dependence of the force with which the air springs acts on the elements of the rollingstock on its deformation was obtained, and energy dissipation when changing the parameters of the connecting element was investigated. Using of the selected thermodynamic model of the air spring in the spatial model of high-speed rollingstock will further allow assessing its dynamic performance when interacting with the railway track, traffic safety indicators and choosing the optimal parameters of the rolling stock and railway track at the design stage.