Railway transport is the foundation of the transport complex and part of the transport network of logistics chains. However, significant deterioration of rolling stock units (especially freight cars accounting for the greater part of all transportation) is an urgent problem of the rail industry. Therefore, the problems of renovation of the existing freight car fleet by developing and introducing domestic models which can effectively compete in terms of the technical and economic and operational indexes are of crucial importance. But the car structure suffers from various deformations at all service stages (production, maintenance and operation). The main type of these deformations is residual ones developing during the welding procedure, due to the thermal effect. Therefore, the issues concerning elimination of these deformations in production and maintenance are becoming ever more urgent. In particular, the most recognized and economy-oriented approach in the field is the one based on the thermal leveling of welded structures. The implementation of this approach requires some research aimed at scientific substantiation of the thermal leveling, as well as, specification of forms and heating temperatures, determination of heating form sizes, thermal leveling simulation and experimental verification of the results, optical microscopy and determination of mechanical characteristics.
Зазначена важлива роль залізничного транспорту в дорожньо-транспортному комплексі України. Відмічено, що в сучасних умовах господарювання, конкуренції зі сторін інших видів транспорту та закордонних залізничних компаній перед вітчизня-ними залізницями гостро стоїть проблема постійного підвищення ефективності використання їх рухомого складу, переважна більшість якого приходиться на вантажний вагонний парк. Обґрунтована актуальність підвищення надійності вітчизняного парку вантажних вагонів. Зазначена роль зварювального виробництва при створенні нових та модернізації існуючих ванта-жних вагонів. Відмічена доцільність заміни методу холодної правки післязварних деформацій, які виникають при виготов-ленні технологічно-деформованих верхніх обв'язувань піввагонів на метод теплової безударної правки. Наведені результати математичне моделювання процесу термічної правки технологічно-деформованих верхніх обв'язувань піввагонів.Ключові слова: залізничний транспорт, рухомий склад, вагонний парк, піввагон, несучі системи, технологічно-деформоване верхнє обв'язування, термічна правка, математична модель, допоміжні графіки.Выделена важная роль железнодорожного транспорта в дорожно-транспортном комплексе Украины. Отмечено, что в совре-менных условиях хозяйствования, конкуренции со стороны других видов транспорта и зарубежных железнодорожных ком-паний перед отечественными железными дорогами остро стоит проблема постоянного повышения эффективности использо-вания подвижного состава, подавляющее большинство которого приходится на грузовой вагонный парк. Обоснована акту-альность повышения надежности отечественного парка грузовых вагонов. Выделена роль сварочного производства при соз-дании новых и модернизации существующих грузовых вагонов. Обоснована целесообразность замены метода холодной правки послесварных деформаций, которые возникают при изготовлении технологически-деформированных верхних обвя-зок полувагонов, на метод тепловой безударный правки. Приведены результаты математическое моделирование процесса термической правки технологически-деформированных верхних обвязок полувагонов.Ключевые слова: железнодорожный транспорт, подвижной состав, вагонный парк, полувагон, несущие системы, тех-нологически-деформированная верхняя обвязка, термическая правка, математическая модель, вспомогательные графики.An important role of railway transport in the road transport complex of Ukraine is highlighted. It is noted that in the current conditions of management, competition from other modes of transport and foreign railway companies, the problem of constant increase in the efficiency of rolling stock use, the overwhelming majority of which falls on the freight wagon fleet, is acute before the domestic railways. The urgency of increasing the reliability of the domestic fleet of freight cars is substantiated. The role of welding production in the creation of new and modernization of existing freight cars is singled out. The expediency of replacing the method of cold dressing of post-welded deformations that arise in the manufacture of technologi...
Purpose. The proposed study is aimed at justifying the expediency of using the thermal leveling method to correct deformations of car metal structures that take place during their manufacture, operation and repair. Methodology. To achieve this purpose a mathematical apparatus was created, which is based on the methods of mathematical design of the experiment. A generalized universal mathematical record of the optimization study of the thermal leveling of car structures has been developed. Modelling of thermal leveling, using the software complex of CAD systems of Solid Works was carried out, as well as an experimental study of the full-size sample of the cantrail in the gondola car. Findings. On the basis of a generalized mathematical record of the optimization study of the thermal leveling of the railcar constructions, mathematical dependencies were created for the thermal leveling of the center sill and the cantrail in the universal gondola cars. These dependences describe the change in the magnitude of the deformation deflection with the corresponding geometric parameters in the heating zones (deflection of the center sill and the profile of the cantrail) depending on the variation of the controlled variables (geometric parameters of the heating spots and temperature). Auxiliary graphs (binary sections) have been constructed for a reasonable choice of the optimal values of the geometric parameters in the heating zones when using thermal leveling of the occurring deformations in the elements of freight cars during their manufacture, repair and operation. Based on the developed finite element models, the efficiency of thermal leveling has been confirmed. The accuracy of the effect obtained in the course of computer simulation is proved experimentally – elimination of the occurred deflection when applying the welding seam in the element of the car structure was noted). Originality. The developed mathematical apparatus and the model created on its basis for the study of the thermal correction in the car structures allow us to justify the selection of the optimal parameters of the marked correction when they are used to eliminate the deformations that occur in the elements of the freight cars. Practical value. Accounting of the obtained results will help to reduce costs in technological processes in the manufacture and repair of freight cars, which is the basis of the rail car fleet of Ukraine.
Calculations of strength, forecasting the residual operation life for repairing traction gears (TG) is carried out on the results of modeling their motion characteristic, which is based on the determined coordinates of the contact points of the gear and wheel profile for the period of engagement (engagement line). This article presents results of a study aimed at developing mathematical dependencies for a refined determination of TG engagement line with the established wear of gear teeth. Adequacy verification of proposed mathematical descriptions was carried out based on the results of the study of new TG of ER-2 electric train series. Their comparison with the coordinates of the engagement line, calculated by the traditional method, showed that modelling uncertainty does not exceed 0.06%. As an example of practical use of the received mathematical descriptions, results of research of motion characteristic of new TG of ER-2 electric train series with the established degrees of wear of gear and wheel teeth are presented.
This paper presents an issue of rolling stock pulling drive gear (PDG) reliability assessment in operation, considering the gear and pitch wheel wear. Among main damages attributive to gear and pitch wheel reject are cheeping of teeth, peeling, plastic deformation. It is noted that the PDG reliability assessment shall be reasonably carried out upon a significant probability of their fail-safe operation that is determined by the rolling contact fatigue resistance. The provided mathematical study design on the PDG reliability assessment of ER-2 electrical multiple train and the corresponding mathematical model PH .=f(Δ 1 , Δ 2 ) is developed. The auxiliary curve is added to the reasonable selection of gear-pitch wheel pair. The provided materials allow to reasonably select gear-pitch wheel pairs obtaining the maximum pulling drive gear fail-safe operation probability values that result in the reliability increase. Recommendations on the further application of the suggested approach during repair of pulling drive gears of modern rolling stock are provided.
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