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Institution

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

EducationDnipro, Ukraine
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.


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Journal ArticleDOI
TL;DR: In this paper, the authors proposed a method to improve the quality of the data collected from the users of the service provider by using the information gathered from the user's own data.
Abstract: Мета Наукова робота має за мету розробку методів розрахунку переробної спроможності сортувальних гірок для умов втрати уповільнювачами гальмової потужності Методика Функціонування сортувальних гірок пов’язано з дією значної кількості випадкових факторів, таких як: характеристики відчепів, умови зовнішнього середовища, величина гальмової потужності, що реалізується уповільнювачами, та ін У зв’язку з цим для дослідження поставлених задач використовуються методи імітаційного моделювання та математичної статистики Визначення швидкості та часу руху відчепів по маршрутах здійснюється на підставі моделювання їх скочування з сортувальної гірки Результати У випадку, якщо гальмової потужності уповільнювачів спускної частини гірки недостатньо для зупинки ними відчепів, то під час розпуску повинні передбачатись перерви для звільнення попередніми відчепами маршрутів скочування З використанням методів теорії ймовірності визначені залежності, що дозволяють встановлювати тривалість вказаних зупинок У випадку, якщо гальмової потужності уповільнювачів на спускній частині гірки та на сортувальних коліях недостатньо для виконання вимог прицільного регулювання швидкості скочування відчепів, то необхідно використовувати додаткове башмачне гальмування В дослідженні розроблені методи, які на підставі імітаційного моделювання сортувального процесу дозволяють встановлювати потрібну величину збільшення тривалості розпуску, що забезпечує безпеку руху при заданій кількості регулювальників швидкості руху вагонів Наукова новизна В роботі авторами вперше запропоновані удосконалені методи визначення переробної спроможності сортувальних гірок Їх особливість у тому, що вони (на відміну від існуючих) дозволяють враховувати технологічні обмеження, що викликані вимогами безпеки сортувального процесу і можуть застосовуватись для оцінки показників роботи гірок в умовах параметричних відмов уповільнювачів Практична значимість Застосування запропонованих методів дозволяє для існуючих обсягів роботи оцінювати вплив несправності уповільнювачів на погіршення показників роботи сортувальних гірок

2 citations

Journal ArticleDOI
TL;DR: A technique for constructing a dynamic model of oscillations of railway vehicles as a system of rigid bodies connected by rigid, elastic and dissipative elements using a hierarchical graph makes it possible to obtain equations of motion in an easily algorithmized manner.
Abstract: Purpose. The scientific work is intended to develop a methodology for describing the structure of the railway vehicles (they are considered as a system of rigid bodies connected by rigid, elastic and dissipative elements), which would allow us to obtain the equations of motion in an easily algorithmized way. Methodology. When constructing the model, authors tend to ensure that its structure reflects the structure of the mechanical system, that is, parts of the model must correspond to parts of the car. In this case, the model takes the form of a hierarchically organized graph whose vertices correspond to the bodies, attachment points of the connecting elements and to the connecting elements themselves, and the edges describe the sets of processes that are related to the incident vertexes. As a rule, these are movements and forces: for the edge between the body and the attachment point they are generalized movements of the body and the general forces acting on it; for the edge between the attachment point and the connecting element - the movements of the point and the forces arising in the element. To each vertex there corresponds a group of equations describing the motion of the system. The nature of the equations depends on the type of the vertex. For the body it is the equations of body motion; for the point - the expressions for the point displacements through generalized displacements of the body and generalized forces acting on the body, through the forces arising in the connecting element; for the connecting element - the expression for the forces arising in it through the deformation of the element. The graph can be regarded as oriented. The direction of the edge is chosen in such a way that for each vertex the values on the right-hand side of the vertex-associated equation would correspond to the incoming edge, and in the left-hand side - to the outgoing edge. Findings. A technique for constructing a dynamic model of oscillations of railway vehicles as a system of rigid bodies is developed on the basis of their description using hierarchically organized graphs. The technique was tested to construct a model of spatial oscillations of a 4-axle freight car with an axial load of 25 tons in Simulink package. Originality . For the first time, a technique has been developed for describing the structure of a railway vehicle using a hierarchical graph, which makes it possible to obtain equations of motion in an easily algorithmized manner. Practical value. The proposed methodological approach will allow, after creating a library of bodies and connecting elements, to significantly reduce the time spent on modeling the oscillations of different vehicles.

2 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the methods of mathematical simulation of railway rolling stock dynamics, as well as the linear algebra methods to assess the stability of solutions of the linear homogeneous differential equations.
Abstract: Purpose. The work is devoted to the study of horizontal oscillation and the assessment of the motion stability of a single wheelset with independent wheel rotation, and to the comparison of stability indicators of the typical wheelset and the wheelset with independent wheel rotation. This is connected with the necessity to increase traffic speed of rolling stock, improve road safety and comfort of passengers. Methodology. To achieve this purpose we used the methods of mathematical simulation of railway rolling stock dynamics, as well as the linear algebra methods to assess the stability of solutions of the linear homogeneous differential equations. Findings. To solve the set task the design model of a single wheelset with independent wheel rotation was created. The wheelset is not a single solid body; each of the wheelset axles has a surplus degree of freedom. Thus, we obtained the system with 4 degrees of freedom. The design model allowed to obtain the system of linear homogeneous differential equations describing the oscillations of the represented wheelset in a horizontal plane on a straight track section. On the basis of the computer modeling were calculated the eigenvalues of the differential equation system coefficients and the asymptotic stability analysis of the wheelset motion with independent wheel rotation. The increment and the frequency of fluctuations were compared with similar indicators for the standard wheelset. The authors also discussed non-oscillatory forms of the wheelset motion and the issues of wheelset self-centering on the track. Originality. The result of the work is the mathematical model of the sinuous movement of a single wheelset, in two-dimensional formulation, with independent wheel rotation and the estimate of the dynamic indices during its motion on a straight track section without any irregularities. There were also proposed the ways to ensure the self-centering on the track of the wheelset with independent wheel rotation. Practical value. The developed mathematical model of the single wheelset motion with independent wheel rotation can be used to create the advanced designs of railway running gear of cars.

2 citations

Journal ArticleDOI
01 Jun 2019
TL;DR: In this article, the authors defined the regularities of stress state of unsupported working occurring in a layered massif and developed a finite-element model of the above working, where the elastic moduli of the matrix and the layer varied greatly, while its position was unchanged.
Abstract: The paper defines the regularities of stress state of unsupported working occurring in a layered massif. The relevance of the performed research is substantiated by the importance of determining the stresses of the contour of unsupported working when the elastic modulus of the matrix and the layer is varied. Since the application of analytic methods for this case is complex, we used a numerical finite element method, implemented in the SCAD. We developed a finite-element model of the above working, where the elastic moduli of the matrix and the layer varied greatly, while its position was unchanged (the layer laying in the middle of the working). The results of the numerical analysis allowed us to build the regularities of three stress components. In order to normalize cases of elastic modulus variation, a dimensionless χ -parameter is introduced which characterizes the relation between the elastic modulus of the matrix and the layer. The obtained regularities of the stress state of the χ-parameter have a functional character and allow to determine the stresses on the contour of the unsupportedworking, depending on the relation between the elastic moduli of the matrix and the layer for all possible spectrum of these parameters.

2 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the friction coefficient influence on the car dynamic loading using new approaches to solving the problem of predicting the rolling stock dynamics, and the results have found their scientific use in a number of author publications in special scientific and popular publications.
Abstract: Purpose. The main requirements for the design of a new generation of cars, according to the Program of rolling stock renovation, are the requirements reducing the operating costs and increasing the cost-effectiveness of their use, taking into account the achievements of scientific and technical thought. Due to the urgency of this subject the paper is devoted to the study of the friction coefficient influence in the bearing connection « center plate – center bowl – bearers » of freight cars on their main dynamic parameters – coefficients of horizontal and vertical dynamics, body acceleration, frame strength, derailment stability factor. Methodology. The study was conducted by numerical integration and mathematical modeling of the freight car dynamic loading using the software package «Dynamics of Rail Vehicles» («DYNRAIL»). Findings . Investigations have shown that the safety movement parameters are influenced by both the friction parameters in bearing connection « center plate – center bowl – bearers » of freight cars in empty and loaded state with bogies TSNII-X3 (model 18-100). Effect have other components of freight car dynamics, namely: radii of curved track sections, height of outer rail, etc. Originality. The author investigated the friction influence on the car dynamic loading using new approaches to solving the problem of predicting the rolling stock dynamics. Prediction was carried out on the basis of significantly updated theoretical material that covers all history of the friction theory and includes the results of recent experimental studies because of the speed on the straights and curves of small-and medium-range sections of the road. Practical value. The obtained results have practical orientation. During the research and after modeling with the improved method of accounting of friction processes dependencies of main dynamic parameters of a four-freight gondola on the value of the friction coefficient in the "body – bogie" with regard to speed were obtained. The results of scientific studies have found their scientific use in a number of author publications in the special scientific and popular publications.

2 citations


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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
20222
202131
202057
201984
201859