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.

Energy efficiency determination of loading-back system of electric traction machines

Abstract: Purpose. Acceptance post-repair tests of electric traction machines are conducted on loading-back stands that reduce the overall power costs for the tests. Currently a number of possible circuit designs of loading-back systems of electric machines are known , but there is no method of determining their energy efficiency. This in turn makes difficult the choice of rational options . The purpose of the article is the development of the corresponding methodo-logy to make easier this process. Methodology . Expressions for determining the energy efficiency of a stand for testing of electric traction machines were obtained using the generalized scheme analysis of energy transformations in the loading-back systems of universal structure . Findings . The t echnique was offered and the analytical expressions for determining the energy efficiency of loading - back systems of electric traction machines were obtained . Energy efficiency coefficient of loading - back system is proposed to consider as the ratio of the total action energy of the mechanical and electromotive forces , providing anchors rotation and flow of current s in electric machines , which are being tested, to the total energy, consumed during the test from the external network. Originality. T he concept was introduced and the analytical determination method of the energy efficiency of loading-back system in electric traction machines was offered. It differs by efficiency availability of power sources and converters , as well as energy efficiency factors of indirect methods of loss compensation . Practical value. The proposed technique of energy efficiency estimation of a loading-back system can be used in solving the problem of rational options choice of schematics stands decisions for electric traction machines acceptance tests of main line and industrial transport .

To the modeling issues of life cycle of deformation work of the railway track elements

Abstract: Purpose. This article highlights the operational cycle modeling of the railway track elements for the development processes study of deformability as the basis of creating a regulatory framework of the track while ensuring the reliability of the railways. Methodology. The basic theory of wave propagation process in describing the interaction of track and rolling stock are used to achieve the goal. Findings. The basic provisions concerning the concept «the operational cycle of the deformation track» were proposed and formulated. The method was set. On its base the algorithm for determining the dynamic effects of the rolling stock on the way was obtained. The basic principles for the calculation schemes of railway track components for process evaluation of the deformability of the way were formulated. An algorithm was developed, which allows getting the field values of stresses, strains and displacements of all points of the track design elements. Based on the fields of stress-strain state of the track, an algorithm to establish the dependence of the process of deformability and the amount of energy expended on the deformability of the track operation was created. Originality . The research of track reliability motivates the development of new models, provides an opportunity to consider it for some developments. There is a need to define the criteria on which the possibility of assessing and forecasting changes in the track states in the course of its operation. The paper proposed the basic principles, methods, algorithms, and the terms relating to the conduct of the study, questions the reliability of the track. Practical value . Analytical models, used to determine the parameters of strength and stability of tracks, fully meet its objectives, but cannot be applied to determine the parameters of track reliability. One of the main factors of impossibility to apply these models is a quasi-dynamic approach. Therefore, as a rule, not only one dynamic process of the railway track is prepared and assayed, but also its consequences. In addition, such models are flat, that also adds some complexity to compare the results with the experiment, since the process is not easy to distinguish the bulk of its limited influence in parts. The application of numerical methods extends the capabilities, and makes it impossible to consider the dynamic process, because it is impossible to introduce the processes that govern the response to the load. Therefore, the proposed modeling makes it possible to examine directly the dynamic process and evaluate the process due to the new criterion, the operational cycle of the strain gauge.

Cognitive dynamics of historical and anthropological studies at the хх and early ххі centuries

Abstract: We study the logical and methodological aspects of historical and anthropological studies in the twentieth and the beginning of the XXI century

Determination of dynamic loads from the wheel on the rail for high-speed trains

Abstract: Purpose . On the basis of theoretical assumptions and experimental studies the paper provides the choice of the factors for the formation of dynamic load on the track of modern rolling stock in the conditions of high-speed. This results in a calculation method of determining a vertical force which acts on the wheels on the rails. Methodology . The current trend of development of transport networks is the introduction to Ukrainian railways speed, and in the future – high-speed, passenger trains. Fundamental structural changes in these trains, and a significant increase in speed results in a need to revise the calculation methods of action of rolling stock on the railway track, the ratio of the standard deviations of various dynamic forces, assess the impact of different factors for different speeds. In the work investigated the change in the dynamic load on the results of experimental measurements. Findings . The dependences of the average and the calculated forces on the speed of modern passenger trains were obtained. Using factor analysis of variance obtained numerical characteristics of the influence of different factors on the value of the vertical force acts on the wheel rail and the degrees of influence of various factors on its deformation were determined. Based on the results of experimental and theoretical research, the necessity of revising the methodology for determining the estimated power for practical calculations the way to strength in terms of passenger trains at high speeds was grounded. Originality . On the basis of theoretical research and analysis of statistical data of experimental measurements it was found that the main factor driving the dynamic vertical force component for modern passenger trains are the vibrations of the «wheel-rail» system or so-called «dynamic wheel passing the rough ways». Practical value. Existing methods of calculating the dynamic component of the vertical forces need such indicators as the reduced mass of the way. The obtained results in the study indicate that a parameter is artificial and can only be used for low speeds at the level of static calculation schemes.

The distribution modeling of impurities in the atmosphere with taking into account of terrain

Abstract: The 2D numerical model to simulate the pollutant dispersion over complex terrain was proposed. The model is based on the equation of potential flow and the equation of admixture transfer. Results of the numerical experiment are presented.