Browsing by Author "Muradian, Leontii A."
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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 Possibility of Using Removable Equipment for Transporting 20- and 40-Feet-Long Containers on an Universal Platform Wagon(Technology Center, Kharkov, Ukraine, 2021) Shaposhnyk, Vladyslav Yu.; Shykunov, Oleksandr A.; Reidemeister, Alexey G.; Muradian, Leontii A.; Potapenko, O.EN: An important role in the market of transport services belongs to container transportation. Railroads, especially under the conditions of increased competition from road transport, must respond quickly to the needs of the market and the growing demand for container transportation, including interstate traffic. Demand for container transportation can vary significantly during the year, which testifies to the expediency of introducing removable equipment on universal railroad freight cars that are involved in the deliveries of containers. This paper reports the design of a removable frame structure for a universal platform that could carry two 20-ft or one 40-ft container. The proposed technical solution does not require changes in the structure of the car and changes in its model; with a decrease in the demand for container transportation, it would allow this car to be used for its main purpose. According to the current methodology, the efforts that operate on the frame during the transportation of containers have been determined. The strength of the proposed structure was estimated by a finite-element method. The maximum stresses arising in the proposed structure are 164.4 MPa; they occur in the corners of the stops attached to the stand-up staples of the platform. The resulting stress values do not exceed the allowable ones. The results of calculating the removable equipment indicate its sufficient strength. Requirements for placing cargo on the rolling stock assume a mandatory check to fit the dimensions, which confirmed that the container hosted by the frame does fit them. The proposed structure makes it possible to abandon disposable fastening parts, improve the safety of container transportation, and increase competitiveness in the container transportation market.Item Improvement of the Open Wagon for Cargoes which Imply Loading with a "Hat"(IOP Publishing, 2020) Reidemeister, Alexey G.; Muradian, Leontii A.; Shaposhnyk, Vladyslav Yu.; Shykunov, Oleksandr A.; Kyryl’chuk, Oleg A.; Kalashnyk, Volodymyr O.EN: The goal of the article is to evaluate the possibility of improving the design of an open wagon body in order to improve traffic safety when transporting cargoes whose height is beyond the upper belt of the side wall (cargo loading with a “hat”). To achieve it, the authors have proposed a variant of a pull-out bar in a wall rack. In lazy state such bars located inside racks, but during transportation of timber, pipes etc they are pulled out above the wall upper belt to prevent cargo from rolling out. These bars are quite light (mass of one pull-out bar is equal to 3 kg, that corresponds to 36 kg of an additional equipment per a wagon), but they considerably facilitate fixing cargo in an open wagon replacing additional wooden fixing racks. It also makes the transportation more reliable due to elimitation the possibility of skew and jamming of fixing equipment. Strength of the proposed element and the entire wagon side wall is estimated with the finite element method. The proposed bars withstand normative loads, and holes in the upper belt for them do not lead to desrease of the wall carrying capacity.Item Influence of Diagnostics of Axle Boxes of Freight Cars on Traffic Safety of the Railway Transport(IOP Publishing, 2021) Pitsenko, Iryna V.; Muradian, Leontii A.; Myamlin, Serhiy V.EN: Abstract. Failures of axle boxes of freight cars due to poor-quality repair and maintenance can be reduced by applying diagnostic methods and tools. Therefore, the study carried out a study of the influence of diagnostics of axle boxes of freight cars on traffic safety of the railway transport. To reduce the magnitude of risks arising from failures of axle box units of freight cars, it is proposed to use vibration diagnostics during maintenance and repair, and to exclude the human factor, it is proposed to completely eliminate the operator's influence on the conclusions of the diagnostic process. Also, a method for assessing the risks arising from failures of axle boxes of freight cars was developed. The presented method for assessing of traffic safety the railway transport allows you to determine and predict risks. Vibration diagnostics allows reducing the risks arising from failures of axle boxes of freight cars, thereby increasing the level of traffic safety up to 3.7 times. In this regard, it can be argued that the use of vibration diagnostics during the maintenance and repair of axle boxes of freight cars makes it possible to reduce the threats to human life and possible harmful environmental consequences on the railway transport.Item The Method of Assessing Traffic Safety in Railway Transport(IOP Publishing, 2021) Bulakh, Marina O.; Baranovskyi, Denis M.; Muradian, Leontii A.EN: Abstract. To identify and predict risks in the work, a method for assessing traffic safety in railway transport is proposed. On the basis of statistics on the failure of freight cars during operation, the characteristic distribution laws for types of wear were determined. As a result, the dependences of the probability of failure-free operation of freight cars on the operating life were obtained and the centers of gravity of the areas that are used to characterize and assess the risk were determined. When designing a freight car, it is possible to establish risk values obtained on the basis of statistical data, which opens up the possibility of improving traffic safety in railway transport. In the developed method for assessing traffic safety in railway transport, the use of a graphical risk matrix is proposed. It is also proposed to combine the dependencies of the probability of failure-free operation of freight cars to calculate the total risk. This allows you to get a graphical risk matrix taking into account three types of wear of a freight car to assess traffic safety. The number of dependencies of the probability of failure-free operation of freight cars can be increased if failures are observed for other reasons.Item Predictive Model of Risks in Railroad Transport when Diagnosing Axle Boxes of Freight Wagons(SAGE Publishing, 2023) Muradian, Leontii A.; Pitsenko, Iryna; Shaposhnyk, Vladyslav Yu.; Shvets, Angela O.; Shvets, Anzhelika O.ENG: This article presents a mathematical model of the risk of failures, depending on the operating parameters, of locomotive diesel engines. The purpose of this study is to determine the risk of failures of locomotive diesel engines in maintenance. The theory of probability and the theory of logic and reliability are used in this theoretical study. The innovations and main works are the first approaches to calculating the risk of failures of locomotive diesel engines by hourly fuel consumption, which, under operational conditions, allows for extending the life of locomotive diesel engines during maintenance. As a result, a maintenance process for 5D49 diesel engines is developed in a locomotive depot. When managing the maintenance processes of 5D49 diesel engines in the locomotive depot, it is determined that the optimal mileage is 45,000 km. The resource of 5D49 diesel engines in the locomotive depot increased by 2.4% in the management of the maintenance process compared to the existing maintenance system.Item Predictive Model of Risks in Railroad Transport when Diagnosing Axle Boxes of Freight Wagons (preiew)(SAGE Publishing, 2022) Muradian, Leontii A.; Pitsenko, Iryna; Shaposhnyk, Vladyslav Yu.; Shvets, Angela O.; Shvets, Anzhelika O.ENG: The research is aimed at developing a predictive model of the risks in railroad transport when using diagnostics of the axle boxes of freight wagons, which will allow assessing traffic safety during the operation of freight wagons. To develop a predictive model of the risks in railroad transport, the approaches of the probability theory were used. The constructed predictive model of the risks makes it possible to assess traffic safety during freight transportations; to determine further measures to reduce them; to evaluate the diagnostic method. The authors developed a predictive model of the risks in railroad transport when using the diagnostic methods of freight wagons’ axle boxes during maintenance and repair of axle box. This model includes the probability of failure-free operation of the axle boxes of freight wagons, the probability of identifying of the technical condition of the axle boxes of freight wagons, the significance of the diagnostic parameter and its relative assessment after appropriate maintenance, repair or technical control.Item Probabilistic-Physical Approach to Describe and Determine the Reliability of Cars(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2016) Muradian, Leontii A.EN: Purpose. The article aims to develop an algorithm and a sequence of description and determination of car reliability to predict certain quantitative indicators of the studied elements, parts and units, or a car as a whole on the basis of probabilistic-physical approach. Methodology. For the calculation of the indicators of reliability, durability and safety of cars the probabilistic-physical method was used, which takes into account the resources consumption inevitable in the operation of cars. The methodology of quantifying the reliability is based on the study of the physical-mechanical and physical-chemical properties and parameters of various elements, with the identification of principles of the aging processes of the elements or parts (with operating time) to determine the analytical dependencies of these processes from the indicators of cars reliability. Findings. On the basis of probabilistic-physical approach it was developed a model to describe and determine the reliability of the cars. At this the method of calculation based on probabilistic-physical model is fundamentally different from all known rigorous probabilistic methods by the fact that it considers a continuous set of states of the elements, parts and systems of the car during continuous time. If there exists or (if it possible to find) the information parameter about the resource consumption of the car element with evaluation of its change speed, and knowing its limit, based on the built car reliability model with the involvement of probabilistic-physical approach, one can predict all the necessary quantitative indicators of reliability of the studied elements, parts and units or a car as a whole. Originality. The methodology of the reliability construction with the use of probabilistic-physical model with DN-distribution was further developed in the article. The specific physical interpretation of the constants of DN-distribution of failures makes it possible to evaluate them according to the results of the study of certain parameters characterizing the technical condition of the car. On the basis of probabilistic-physical approach the algorithm and the sequence of description and determination of cars reliability to predict certain quantitative reliability indicators of the studied elements, parts and units, or a car as a whole were developed. Practical value. The results make it possible to calculate in practice the quantitative indicators of reliability of cars or their individual elements for further prediction of the overall reliability during operation.Item Some Dynamic Processes at Longitudinally-Transverse Shift of the Cargo(Silesian University of Technology, Poland, 2023) Muradian, Leontii A.; Shvets, Anzhelika O.; Shvets, Anzhela O.ENG: The purpose of the work is to study the influence of the longitudinally-transverse shift of the cargo’s center of mass on the dynamic loading of the wagon in order to solve the problem of predicting the dynamics and stability of an asymmetrically loaded railroad vehicle. During the analytical simulation, a multibody model of the spatial oscillations of the wagon was used. The differential equations of wagon oscillations are compiled using the d'Alembert principle, while the wagon is considered as a system with 42 degrees of freedom. The work presents the results of analytical simulation of some dynamic processes of interaction of railroad vehicles with the rails on the example of flat wagons. The results of the analytical simulation are presented, taking into account the speed of movement along the curved sections of the railway track. The proposed multibody model "heavy cargo – wagon" makes it possible to analytically determine the dynamic characteristics of the system and ensure the development of such methods of transportation of heavy cargo that meet the requirements of train traffic safety. The application of the obtained results will help improve the running safety of freight wagons and enhance the technical and economic performance of railways.