Browsing by Author "Kovalchuk, O."

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    Preservation of Macro Fractographic Signs of the Plane of Fracture of the Details for Expert Engineering Research
    (Technical University, Academic Publishing House, Sofia, 2019) Batig, Andriy V.; Hrytsyshyn, Petro; Kovalchuk, O.; Kuzyshyn, Andrii Ya.; Dovhaniuk, Stepan S.; Sobolevska, Yuliia H.
    EN: Estimates of operational reliability and durability of machine parts and mechanisms cannot be carried out without technical diagnostics of the presence or absence of fatigue cracks, which are the cause of destruction. In some cases, the object of investigation, which is a material proof in the execution of expert engineering studies, may be accidentally or deliberately damaged or destroyed. This leads to the loss of specific signs of the presence of fatigue cracks and the inability to identify patterns that led to their appearance. Ultimately, this affects the reliability of the results. For example, such circumstances in the future significantly complicate the identification of the true causes of accidents and disasters on the railway. Preserving the plane of fracture of the object of research at the scene of the incident and in the process of its transportation to a research institution is an important factor in increasing the reliability of expert engineering and technical opinion taking into account the requirements of the European Union technical specifications (TSI).
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    Study of the Interaction of the Railway Track and the Rolling Stock Under Conditions of Accelerated Movement
    (IOP Publishing, 2020) Hubar, Oleksіy V.; Markul, Ruslan V.; Tiutkin, Oleksii L.; Andrieiev, Volodymyr S.; Arbuzov, Maxim; Kovalchuk, O.
    ENG: Comprehensive studies of the interaction of the railway track and the investigated rolling stock under accelerated conditions have been carried out. The basis of the research was to obtain and substantiate the process of stress state, force interaction of the railway track and the rolling stock under conditions of accelerated movement. Introduction of the new rolling stock into continuous operation is a serious task that must be solved comprehensively. The implementation of this direction significantly affects the reliability of the elements of the railway track. Within the framework of the research, the approach was used that takes into account theoretical and experimental parts of the research using the methodology of prof. O. P. Yershkov. As a result of the studies, average stress values were established: in rails, they variate within the range 44.37...70.99 MPa; in the sleeper, they reach 0.78 MPa; in the ballast layer, they have 0.13 MPa; in the body of the subgrade, they reach 0.04 MPa, which is significantly less than the maxima allowable values. While speed change from 140 to 160 km/h, the values of the studied parameters decrease: vertical force (9.39 %), lateral forces (19.79 %); stresses in the edge of the rail flange (15.86 %); stresses in the edge of the rail head (16.67 %); stresses in the neck of the rail (8.74 %). The obtained results made it possible to form trends and recommendations on the feasibility of further increasing speeds development. At the same time, this made it possible to substantiate in more detail the operation of the railway track in the case of accelerated movement.