Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan

About: Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan is a education organization based out in Dnipro, Ukraine. It is known for research contribution in the topics: Track (rail transport) & Bogie. The organization has 736 authors who have published 655 publications receiving 1468 citations. The organization is also known as: Institute of Railway Transport Engineers.

Determination the permissible forces in assessing the lift resistant factor of freight cars in trains

Abstract: Цель . В аналитическом исследовании рассматриваются: 1) связь между продольной силой, действую-щей на вагон в составе поезда; 2) боковые и вертикальные силы взаимодействия в зоне контакта колеса и рельса; 3) динамические показатели вагонов с величиной коэффициента запаса устойчивости от выжимания; 4) получение зависимостей между ними. Методика . Исследование проводилось аналитическим методом оценки устойчивости грузового вагона при движении с различными скоростями по прямым и кривым участкам пути. Результаты . В процессе исследования движения поезда, при расследовании транспортных событий, а также во время выполнения учебного задания на тренажере машиниста для оценки его действий используются величины продольных сил в межвагонных соединениях. Получено выражение для вычисления значения продольной сжимающей силы, действующей на вагон, при которой величина коэффициента запаса устойчивости от выжимания равна допустимому значению (критическая сила). Для оценки влияния на величину продольной силы скорости движения, коэффициентов вертикальной и горизонтальной динамики, а также ветровой нагрузки на боковую поверхность кузова вагона приведены результаты расчетов движения порожнего полувагона модели № 12-532 по кривой радиусом 250 м с возвышением 150 мм и поперечным разбегом рамы кузова вагона относительно оси пути в направляющем сечении в 50 мм. Научная новизна . В данном исследовании приведена методика определения продольной сжимающей силы, несколько отличающаяся от общепринятой. Также оценивается влияние на неё скорости движения подвижного состава, коэффициентов вертикальной и горизонтальной динамики и ветровой нагрузки на боковую поверхность кузова вагона. Практическая значимость . Авторами разработаны предложения по уточнению существующих методик определения значения продольной сжимающей силы, действующей на вагон, при которой величина коэффициента запаса устойчивости от выжимания будет равна допустимому значению. Это позволит оценивать устойчивость каждого вагона поезда от выжимания непосредственно во время моделирования его движения. Наиболее эффективно использовать эту методику можно в тренажерах, предназначенных для обучения машинистов безопасным способам вождения поездов, и при расследовании причин схода вагонов.

Development of mathematical models of energy conversion processes in an induction motor supplied from an autonomous induction generator with parametric non-symmetry

Abstract: The paper presents studies of the system "induction generator-induction motor" with parametric asymmetry on a mathematical model to determine the quality of generated electricity in load operating modes. A mathematical model of the "induction generator-induction motor" system has been developed taking into account losses in steel and parametric asymmetry. The analysis of the transient characteristics of an induction generator when a motor load is connected in symmetrical and asymmetrical modes of operation is carried out. The results of changes in the main characteristics of an induction motor at various degrees of parametric asymmetry in the generator are presented. The quality of the generated electricity was analyzed based on the calculations of the unbalance coefficients for each of the operating modes. The assessment of the thermal state in steady-state conditions was carried out using an equivalent thermal equivalent circuit. Thermal transients were investigated when starting an induction motor from an autonomous energy source based on an induction generator. On a thermal mathematical model, the study of the effect of the output voltage asymmetry on the heating of the connected induction motor was carried out. It is shown that the asymmetry of the output voltage of an induction generator reaches 3–10 % and causes overheating of the windings in excess of the permissible values. A regression model has been developed for studying the operating conditions of an induction motor when powered by an induction generator with an asymmetry of the stator windings. The use of the obtained equations will make it possible to determine the most rational combination of factors affecting the heating of the stator windings of induction machines, in which they will not overheat above the maximum permissible temperature values of the corresponding insulation classes

Enhancing the scientific level of engineering training of railway transport professionals

Abstract: Purpose . Publication of the results of international scientific and technical cooperation of the Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan (DNURT, Ukraine) and the Czech Technical University (CTU) in the field of engineering training of students on the basis of modern methods of development of scientific and creative abilities of students. Methodology . The development of scientific thought and the improvement of the professional level of students of engineering specialties of railway technical institutes may be carried out by different methods both during training and during extracurricular time. One of the methods for improving the scientific level of future engineers is the public lectures of renowned scholars and researchers from leading European higher education institutions, enabling students to have access to world-class advanced scientific idea. Findings . The authors have analyzed the activity of DNURT and CTU on scientific and educational preparation of students. It is emphasized that cooperation promotes strengthening of contacts between universities, improves the quality of students' training, is one of the factors of the professional development of future specialists, raising the scientific level of engineering training of railway transport professionals. It is proved that DNURT and CTU duly fulfill the higher education tasks of training of professional personnel who are able to work effectively in the global market, aimed at improving the quality and efficiency of education. Originality . This paper presents the analysis of results concerning the efficiency of application of modern methods for engineering training of students of technical higher educational institutions. It gives extended view of the main directions of international education activities. Practical value . It is confirmed that popularization of modern methods of propagation of engineering thought among student youth has acquired a new meaning and contributes to enhancing the scientific level of engineering training of railway transport professionals.

One Approach to Quasi-Optimal Control of Direct Current Motor

Abstract: The article presents the calculation of the transfer function of the DCM-30-N1-0.2 micromotor DC, obtained a transcendental system of equations for determining the duration of the quasi-optimal control intervals and the dependence of the first control interval on the specified overshoot. The obtained dependence can be used in the engineering methodology for the synthesis of quasi-optimal control and the choice of actuators of the automatic control system.

Railway track representation in mathematical model of vehicles movement

Abstract: Purpose. The tasks of modeling the interaction of track and rolling stock are basic ones for most areas of mo-dern scientific research of railway transport. The compilation of the model by the principle of Lagrange d'Alembert has found a very wide application for solving the problems of rolling stock dynamics. Representation of the railway track in the model of crew movement can be implemented in several ways, which, among other things, will differ in detail. The purpose of this work is to create a methodology for representing the railway track in mathematical mo-dels of interaction with rolling stock and obtaining practical results for different characteristics and design of the track and the level of maximum speed . Methodology. The problem consists of determining such characteristics of the path as the reduced mass, the stiffness coefficient, and the dissipation coefficient. As a tool for solving this problem it was used the model of the stress-strain behavior of the railway track based on the joint use of the elastic wave propagation equations to describe the geometry of the outline of the part of the system space that is involved in the interaction at a given time and the equations of dynamic equilibrium of its deformation. This makes it possible to take into account the dynamics of the deflection of the under-rail base, which is especially important for the conditions of passenger traffic, which can be carried out at high speed . Findings. Theoretically justified stiffness and dissipation coefficients of the railway track for calculating the dynamics of rolling stock in modern models based on systems of equations in accordance with the Lagrange d'Alembert principle are obtained. The established va-lues, in contrast to those given in other sources, have a reasonable dependence on the design of the path and the speed of movement . Originality. The approaches of railroad track representation in models of rolling stock described by systems of equations by the Lagrange-d'Alembert principle are expanded. A method for determining the characteristics of the railway track for such models is developed based on the results of variant calculations of the dynamic deflection of the rail from the passage of the wheel . Practical value. The values of the stiffness and dissipation coefficients of the railway track are obtained depending on the design and speed of motion for practical use in appropriate models of interaction between track and rolling stock.