Browsing by Author "Dovhaniuk, Stepan S."
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Item Coefficient of Stability Against Lift by Longitudinal Forces of Freight Cars in Trains(IOP Publishing Ltd., 2020) Shvets, Anzhela O.; Shatunov, Oleksandr V.; Dovhaniuk, Stepan S.; Muradian, Leontii A.; Pularyia, Andriy L.; Kalashnik, Vladimir A.EN: The paper is devoted to a theoretical study of the car movement stability when exposed to longitudinal forces of a quasistatic nature. The authors obtained the expressions for calculating the resistance coefficient of the car lift by the longitudinal compressive force acting on the car as part of a freight train. The influence of some factor’s combination on the longitudinal forces, at which the car movement stability is still maintained, was analyzed using the analytical dependencies to assess the longitudinal loading of cars in trains. The study was carried out by analytical method for assessing the freight car stability when moving at different speeds along curved track sections. The calculations were made in a curve of small radius taking into account the inertia forces from the unbalanced acceleration. In a theoretical study, the influence of quasistatic longitudinal compressive forces depending on changes in speed and force value, as well as the influence of friction in the wheel flange and rail contact and the eccentricity of fastening the automatic coupler shank on the stability were considered. When applying the results obtained, the stability of freight rolling stock can be increased, which in turn will remove some existing restrictions on the permissible speeds and increase the technical speed of train movement. Using the described methodology for determining the lift resistance coefficient will make it possible to justify the cause of derailment, as well as to develop and put into practice technical measures to prevent the lift of carriages, thrusts and shears of the track.Item Determining the Causes of Rolling Stock Derailment From the Track Using Modern Research Methods(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Kuzyshyn, Andriy; Batig, Andriy V.; Sobolevska, Julia H.; Kostritsa, Sergei A.; Ursulyak, Lyudmila V.; Dovhaniuk, Stepan S.EN: Abstract. The analysis of cases of rolling stock derailment from the track at PJSC «Ukrzaliznytsia» over the past 5 years has been carried out and their main types are given. It is noted that the rapid development and improvement of computer technology allows the use of computer and mathematical modelling in the study of cases of rolling stock derailment from the rail track, which makes it possible to take into account a combination of factors that have the main influence on the behavior of rolling stock when moving along the track. It has been established that the first step is the construction of a mathematical model of an object using a selected type of mathematical description: algebraic, differential, integral equations, discrete mathematics, set theory, and others. And the second step is the choice of a method for solving these models. The simulation methods are given, which, depending on the programming style, are divided into: procedural-oriented, object-oriented, logical-oriented, rule-oriented, and oriented to constraints. An objectoriented programming of a freight car has been developed, which will make it possible to evaluate its main dynamic indicators, in particular, indicators of stability from derailment. This in turn will facilitate the establishment of the main causes of rolling stock derailment from the rail track.Item Improving a Methodology of Theoretical Determination of the Frame and Directing Forсes in Modern Diesel Trains(PC "Technology Center", Ukrainian State University of Railway Transport, Kharkov, 2018) Kovalchuk, Vitalii V.; Kuzyshyn, Andrii Ya.; Kostritsa, Sergey A.; Sobolevska, Yuliia H.; Batig, Andriy V.; Dovhaniuk, Stepan S.EN: The method for determining the directing force was improved, taking into consideration the effect of transverse creep forces and the angle of the directing force inclination to the vertical axis. It was established that when determining the directing force, it is necessary to check the gap between the wheel flange and the rail head which is difficult to realize without computer simulation. When determining the frame force on the axle of the wheel set, a comprehensive approach was adopted taking into account geometric irregularities of the track path, both in vertical and horizontal planes; longitudinal and transverse creep forces at the point of the wheel-rail contact and influence of adjacent wheel sets of the diesel train car. Dependences of the frame and directing forces on speed of the carriage movement and the value of amplitude of the horizontal irregularity of the rail track were obtained. It was established that when moving in the straight section of the track, an increase in speed from 0 m/s to 50 m/s results in a rise in the value of the frame force: up to 8.3 kN for the first wheel set and 19.37 kN for the second wheel set and the directing force up to 31.38 kN for the first wheel set and up to 46.83 kN for the second wheel set. The increase in amplitude of the horizontal irregularity of the track, which is one of the primary causes of occurrence of forced oscillations of the carriage section above the springs also leads to an increase in numerical values of the forces of interaction of the rolling stock with the rail track. All this can bring about an increased power influence of the wheel set on the track and a negative impact on the basic criteria of traffic safety. Influence of the carriage movement speed on the value of transverse creep forces was studied. It has been established that with an increase in the carriage speed from 0 m/s to 50 m/s, these forces grow from 0 to 15.75 kN for the 1st wheel set and from 0 to 29.22 kN for the 2nd wheel set. This indicates impermissibility of neglecting the transverse creep forces when determining the directing force. Comparison of numerical values of the directing force determined by different methodologies was performed. It has been established that the methodology used in conducting forensic examination of railroad accidents may result in underestimation of fulfillment of the derailing condition. At the same time, calculations according to the formula improved in this study give an opportunity to obtain the results most approximate to the real operation conditions. Comparison of the experimental and theoretical calculated values of the frame force acting on the first wheel set of the diesel train car was made and their practical coincidence was shown. Discrepancy of the compared values of the frame force was within 7.2 %.Item Investigation of Possibility of Hopper Cars Unloading on the Car Dumper VRS–134M(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Dovhaniuk, Stepan S.; Kalashnyk, Volodymyr O.; Reidemeister, Alexey G.; Shykunov, Oleksandr A.EN: Abstract. It was developed a computational model to evaluate the body strength of short base hopper models 19-758-01, 20-471, and 20-4015 when unloading them on the car dumper VRS–134M. Modeling of the stress-strain state of the car design was made using the finite element method. It was established that in terms of strength, bodies of the hopper models 19-758-01, 20-471, and 20-4015 are suitable for unloading on car dumper. The results of experimental studies showed sufficiently high accuracy of the chosen computational model for estimating the stress-strain state of design and confirmed the possibility of hopper car unloading on the car dumper VRS–134M.Item 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).Item Research of Safety Indicators of Diesel Train Movement with Two-Stage Spring Suspension(Technical University of Sofia, Bulgaria, 2018) Kuzyshyn, Andrii Ya.; Batig, Andriy V.; Kostritsa, Sergey A.; Sobolevska, Yuliia H.; Kovalchuk, Vitalii V.; Dovhaniuk, Stepan S.; Voznyak, Oleg M.EN: The problem of the interaction of rolling stock with the rail track has been analyzed in the present paper. It has been established that in the process of transport science development a number of methods for determining the causes of wheel pairs derailment are developed, which, in a varying degree, take into account the peculiarities of their interaction. The problem of choosing the most accurate method for estimating the causes of rolling stock derailment becomes more complicated because of the lack of sufficient experimental data that would allow us to verify the adequacy of the models. The indicators of stability of the wheel against derailment, which are used on the railways of Ukraine and Europe, have been examined. Their dependences on the speed of movement were derived. It has been established that the increase of the speed of motion leads to the increase of the interaction power of the rolling stock with the rail track, which may, under certain operational parameters, provoke its derailment. As a result of the calculations, it has been shown that the use of norms for car design and calculation used on Ukrainian railways can lead to an inadequate estimation of traffic safety parameters, since it does not take into account the unevenness of the railway track. It has been established that the requirements of BS EN 14363: 2005 European norms are stricter in comparison with the norms for calculation and evaluation of the bearing elements strength and dynamic qualities of motor-vehicle rolling stock used on Ukrainian railways. A comparison of the experimentally and theoretically calculated values of the stability margin coefficient against wheel derailment of the first wheel pair of the diesel train car was carried out.Item The Results of Brake Tests of the DPKr-3 Diesel Train(IOP Publishing, 2020) Dovhaniuk, Stepan S.; Shaposhnyk, Vladyslav Yu.; Shykunov, Oleksandr A.; Shatunov, Oleksandr V.; Vyslohuzov, Viktor T.EN: SC "Ukrzaliznytsia" purchased the first of three planned regional three-car (two main motor cars and one intermediate) diesel train DPKr-3 manufactured by PJSC “Kryukovsky railway car building works”. To confirm the declared characteristics and safety indicators of the DPKr-3 diesel train, specialists department of Cars of Dnipro National University of Railway Transport named after Academician V. Lazaryan conducted complex certification tests, which confirmed the compliance of the stated parameters. One of the points of the Terms of Reference was to determine the brake pressure of the linings per 100 weight of the train in terms of cast iron brake pads. For this purpose, according to the methodology adopted in the territory of the former CIS, force sensors, which were installed in the tick mechanisms instead of the brake linings, measured the magnitudes of the forces of pressing the brake linings on the disks. However, during the tests it was found out that the current standards for calculating the provision of train brakes cannot be applied to modern rolling stock. It is recommended for rolling stock where the use of brake pads, and even more cast iron, is not provided by the design, to develop normative documents that would determine the standards for brakes by the results of calculations and tests.Item Study of the Dynamic Behavior of Rolling Stock using a Computer Experiment(IOP Publishing, 2020) Kuzyshyn, Andrii Ya.; Batig, Andriy V.; Kostritsa, Sergei A.; Sobolevska, Yuliia H.; Dovhaniuk, Stepan S.; Dzhus, Volodymyr S.EN: The authors of the article analyzed existing software systems that are used to study the dynamic behavior of rolling stock, and also emphasized the importance of using a computer experiment to implement this task. An improved spatial mathematical model of the dynamic behavior of a freight wagon when it interacts with a rail track is considered, and it is proposed to study it using an object-oriented approach using the Maple software package. To accomplish this task by writing procedures, separate modules (subprograms) were created that included differential equations of motion for the individual components of the object under study. Based on existing procedures, the main module was created, which reflected the sequence of performing certain functions (calling up the necessary information, especially the use of logic, methods for solving the problem, as well as visualizing the results). Using the created modules in the Maple software package, a computer experiment was used to study the dynamic behavior of a freight car when it interacted with a rail, and also showed the possibility of taking into account the influence of individual parameters of its technical condition on its dynamic behavior.Item Traction Tests of the Special Self-Propelled Rolling Stock: Aims, Methods, Experience and Prospects(Instytut Pojazdów Szynowych TABOR, 2020) Bolzhelarskyi, Yaroslav V.; Dovhaniuk, Stepan S.; Urshuliak, Oleksandr; Daszkiewicz, PawełEN: Methods and results of experimental determination of the two most important parameters for traction calculations of the DGK-type speeder are given in the article. The first parameter is the specific acceleration, i.e. acceleration from the action of unit of force per unit of weight of the train. The second one is the specific rolling resistance. The results can be used to determine these parameters for different types of OTM.