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.

Rational modes determination of traction motors loading-back for electric rolling stock in mainline and industrial transport

Abstract: Purpose. Loading-back systems are used for post-maintenance acceptance tests of electric traction motors of electric rolling stock (ERS) in mainline and industrial transport. The aim of the research is justification of choice method of the rational loading-back parameters of traction electric motors during the tests for heating. Methodology. At the heart of the choice method justification of the rational loading-back parameters is a theory of heating the homogeneous solid body and well-known methods of heating calculations of traction electric machines. Findings . Expediency of heating tests for electric traction motors at load currents equal to the starting current (for ERS of mainline transport) or fifteen minutes current (for ERS of industrial transport) was substantiated. It was shown that this increase of load current will reduce the electricity costs of the tests for 20–30% and shorten the tests duration for three–four times while ensuring the corrected power minimum of energy sources in loading-back system. Originality. It is shown that the energy costs for heating tests of the traction motors can be reduced by both the increasing the energy efficiency of the loading-back system and by the optimizing of loading mode of traction electric machines. Choice technique of rational modes of loading-back for electric traction motors of rolling stock in mainline and industrial transport was grounded. Practical value . Load current increase of traction electric motors during their tests for heating will reduce the total electricity consumption for the acceptance tests, reduce test time and total material costs for repair of the electric traction motors of rolling stock in mainline and industrial transport.

Scientific evidence for walls fastening technologies of working trench by the special method «slurry wall» for shallow subways' stations

Abstract: Purpose. It’s necessary to carry out justification of fastening technology and the choice of the optimal variant, creating dependency diagrams of moving for idealized cases by means of automated methods of calculations. Methodology. To achieve this goal, the finite element solid models, which reflect the design of the working trench for the shallow subways’ stations, with four ways to fix the “slurry wall”, as well as a calculation and analysis of the stress-strain state of structures and fixtures calculated using the complex with using the finite element method (FEM) is built in the software package SCAD. Findings. The analysis of the stress-strain state and movements of various fundamental systems of soil nailing and comparing the results by displaying the calculations results of main and equivalent stresses, using the built-in postprocessors in software package SCAD. Namely, were identified extreme tensions arising in the wall and strut rail. It is built the tables and the resulting graph of behavior of the structural fastening condition; the parameters change of the surrounding array on the base of the research. It is possible to analyze and compare the operation of different constructions of slopes fastening of working trench by means of their help. Originality. In solving this problem have been analyzed and studied the behavior of the structure fastening the «slurry wall», and its stress-strain state, the location and the fastening areas that need further elaboration, study and introduction of measures to strengthen the construction of fences and auxiliary fixing elements, presented with metal strut rail. Practical value. In the era of highly advanced building technologies in the construction of underground facilities with using the special method of “slurry wall” the question arises about the quick selection of optimal parameters, elements and methods of securing its walls from excessive strain and avoidance of displacement to the calculation of possible combinations of permanent loads from soil in the construction of the working trench.

Dynamic performance of freight cars on bogies model 18-1711

Abstract: Purpose. To analyze the results of study of dynamic parameters of the tank-car model 15-1900 and gondola car model 12-1905, equipped with the bogies model 18-1711 with axle loading of 25 ton and unified according to major parts and joints with the cars of previous generation. According to results of the study to conclude about the possibility of using bogies model 18-1711 as the running parts of the freight rolling stock of the new generation of 1520 mm track with increased axle loading. Methodology. The dynamic performance of the rolling stock running parts directly affects the safety of railway traffic. Experimental studies of the car dynamic qualities are an important step in the modernization of existing bogie constructions and in the creation of the new ones. These tests allow one to confirm the results of theoretical studies and to check the correctness of the constructive solutions. Findings. Basic results of dynamic studies are presented as the graphs of dynamic performance dependencies on the motion speed of the experimental train. Results show that the freight cars on the bogies model 18-1711 have satisfactory dynamic properties meeting current regulatory requirements. Originality. The dynamic characteristics of freight cars on bogies model 18-1711, which give a complete view of the car loading allow us to estimate the dependency of the car dynamic performance on the bogie design parameters. Practical value. The bogie model 18-1711 with axle loading 25 ton can be used as a freight car undercarriages of the new generation of 1520 mm track.

Исследование свойств современных теплоизоляционных материалов

Abstract: Purpose. To study the modern heat-insulating materials presented at the market of Ukraine and to estimate the efficiency of their application. Methodology. Research and analysis of heat-insulating materials presented at the market of Ukraine, according to the existing standards. Findings. To ensure the energy efficiency in buildings and constructions it is necessary to apply the domestic heat-insulating material, which possesses the given thermo technical characteristics, reduced indexes of water absorption, flammability and toxicity, as well as durability and relatively low self–cost. Originality. Basic heat-insulating materials, which are most widely used in construction are systematized, the researches of their properties are conducted and the foam glass is chosen as the most effective heat-insulating material. It is characterized by high thermo technical characteristics and possesses the best ecological indexes, as well as the sturdiness for aggressive factors influence. Practical value. Special attention deserves the insulating material foam glass, which is a synthetic silicate material with evenly placed pores (0.1 ... 5.0 mm) separated by thin septa with a vitreous substance possesses the necessary properties and by aforesaid may be accepted for studies aimed its improvement (modification). The results of researches can be applied in the foam glass production, which is used for heat-insulation of buildings and constructions, equipment, pipelines etc.

The Wavelet Based Detecting of the Signalling Relay Armature Defects

Abstract: The article deals with the problem of automatic detection defects of armature and contact springs in railway signalling relays. Signalling relays are currently basic components in train control systems that ensure train traffic safety and to ensure their reliable operation, the relays are periodically subjected to routine maintenance. Most of the tests for signalling relays are performed manually, which is time consuming and very expensive. For developing the automatic method for detecting and identifying the relay armature defects the investigations were performed with ten different types of neutral signalling relays. For each type of relay, several groups were formed, which consisted of three relays, in which one group contained fully serviceable and properly configured relays, while the other groups contained relays with some artificially created defects in the form of deformed contact springs or defects in the coil or magnetic core. To identify the features of the basic defects of relays, the time dependence of the transient currents were measured during relay switching on and off. Three segments are clearly distinguishable on the transient current curve: the first segment when the anchor is in the initial position and the magnetic circuit is open, the second one when the armature moves from the initial to the final position, and the third one when the anchor is picked up and the magnetic circuit is closed. In the first and third segments the current in the relay coil increases exponentially with time constants depending only on the impedances of the coil, which allows to use these time constants for detecting defects in the relay coil and magnetic circuit. In the second segment the current in the relay coil is determined by electromechanical processes that occur during the movement of the armature, which include magnetic, friction, deformation forces etc., and defects of moving components lead to a change in the shape of transient current curve and to appearance of some features in the form of sags and swells on it. Du to these features are small, using the wavelet decomposition of the transient current dependences for detecting defects of armature in signalling relays was proposed in the work. For prompt detection of all possible armature defects, to use the wavelet Shannon entropy as an integral parameter, the value of which strongly depends on the appearance of any order disturbances in the systems was also proposed in the work. The effectiveness of the proposed methods have been investigated and obtained results confirmed their effectiveness.