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.

The Optimal Thickness of the Surface Plasma Hardening Layer of Functional-Gradient Parts with Symmetrical Stress Concentrators

Abstract: Based on the approaches of continuous mathematical modeling, a computational methodology is proposed for establishing one of the most important operational parameters of surface engineering technologies, which determines the life of parts - the thickness of the hardened layer. For the first time, using non-local models of mechanics and the Fenics finite element analysis package, a scheme for finding the optimal hardening depth of parts depending on the load parameters and characteristics of stress concentrators has been built. Using the example of wheel rims of locomotives, it is shown that in the presence of stress concentrators, the increase in the life cycle of parts is achieved by plasma strengthening to a depth of 2.5… 3.5 times larger than the radius of the concentrators. The methodology proposed in the work is necessary for describing the behavior of the material of parts under the action of force loads in the presence of stress concentrators for selecting the optimal technological modes of hardening the surface layers. The established relationship between the change of properties of local volumes of wheels of locomotives at operational loadings and characteristics of concentrators of tension is used to obtain products with the defined life cycle, computer designing of the technological process of plasma strengthening of surfaces of contact interaction of details.

Research of Mathematical Model of Movement of Six-Axle Locomotives with Controllable Wheelsets Installation

Abstract: Research of mathematical model of movement of six-axial locomotive with controllable wheelsets installation. Based on the general system of nonlinear variable coefficient differential equations of the vehicle movement in a rail track with inequalities in plan, the mathematical model of movement dynamics of locomotive of improved design with the axial formula 30-30 as an object of automatic control of the wheelsets position in the rail track is considered. Movement simulation is performed on the example of a six-axle locomotive at the speeds of movement and parameters of the curvilinear track sections, which coincide with the conditions of the experiment presented in the thesis work of V. N. Yazykov. The article presents research results of the mathematical model of movement of the improved locomotive bogie with controllable wheelsets installation in the curvilinear track sections using the Matlab/Simulink software package. The results of experimental studies of the All-Russian Scientific-Research and Design Technological Institute of Rolling Stock and the performed theoretical studies show that the efficiency of the improved system for controlling the wheelset position is higher than that of the serial design, in all modes of movement. The improved system of automatic control of wheelsets position makes it possible to reduce guiding forces by 35%. The possibility of using the mathematical model of locomotive movement of the axial formula 30-30 of improved bogie design with axle-box links of adjustable length, taking into account the dynamics of the automatic control system of the wheelsets installation in the rail track, is theoretically substantiated. The theoretical research found out the reduction of lateral forces in the improved bogie design during the passage of curvilinear track sections. The use of the explored mathematical model of locomotive movement reduces the volume and complexity of research works, as well as increases the reliability of engineering calculations when designing new and improving existing designs of the locomotive underframe.

Impact mechanisms research in the contact network on rail track circuits

Abstract: Purpose . Еlectromagnetic processes in «contact network-rails-earth» system should be researched for the purpose of electromagnetic compatibility rail circuits with traction power supply system providing and improving traffic safety on railway transport. Methodology . The methods of scientific analysis, mathematical modeling, experimental investigation, scale modeling have been applied to achieve this goal . Findings. Conducted theoretical and experimental investigations, indicate that electromagnetic processes in the « contact network-rails-earth » system in nearest zone in frequency range up to 1 MHz and it give us an opportunity to consider, that electromagnetic field of hindrance consists of two components: electric and magnetic. Each of them has its own mechanism to influence the rail circuits. In consequence of research the theoretical and experimental dependences of electromotive force induced in wire-receiver from the hindrance current frequency have been received. The frequency graph of relative error according to data « theory-experiment » has been received. The adequacy by Wilcoxon criterion of mathematical model to experimental data has been proved. Originality. The results of theoretical and experimental investigations of magnetic influence between two contours gives us a concurrence in frequency range up to 1000 Hz with average relative error 2, 33 % . With hindrance current frequency one can observe certain increasing the average relative error between calculated and measured values of electromotive force induced in the wire-receiver. Practical value. The adequacy by Wilcoxon criterion of mathematical model to experimental data has been proved on significance level 5 % . It gives an opportunity to use this mathematical apparatus for the investigation of electromagnetic processes in lines with plenty of wires and in «contact network-rails-earth» system in range up to 1000 Hz. The obtained results can be useful in designing, researching and providing electromagnetic compatibility of rail circuits with traction power supply system.

Establishment of the permissible train speed on the curved turnouts

Abstract: Purpose. Turnouts play a key role in the railway transportation process. One-sided and many-sided curved turnouts were railed over the last 20 years in difficult conditions (curved sections, yard necks). They have a number of geometric features, unlike the conventional one-sided turnouts. Today the normative documents prohibit laying such turnouts in curved track sections and only partially regulate the assessment procedure of their real condition. The question of establishment the permissible train speed within the curved turnouts is still open. In this regard, authors propose to set the train speed according to the driving comfort criterion using the results of field measurements of ordinates from the baseline for the particular curved turnout. Methodology. The article considers the criteria using which one can set the permissible speed on the turnouts. It defines the complexity of their application, advantages and disadvantages. Findings. The work analyzes the speed distribution along the length of the real curved turnout for the forward and lateral directions. It establishes the change rate values of unbalanced accelerations for the existing norms of the curved track sections maintenance according to the difference in the adjacent bend versine at speeds up to 160 km/h. Originality. A method for establishing the trains’ speed limit within the curved turnouts was developed. It takes into account the actual geometric position in the plan of forward and lateral turnout directions. This approach makes it possible to establish a barrier places in plan on the turnouts limiting the train speed. Practical value. The proposed method makes it possible to objectively assess and set the trains’ permissible speed on the basis of the ordinate measurement of the forward and lateral directions of the curved turnouts from the baseline using the driving comfort criteria. The method was tested using real turnouts, which are located within the Pridneprovsk Railway.

Features of the research work elements deformability of railway track

Abstract: Purpose. The scientific paper is supposed the determination of basic physical and structural conditions in modeling life cycle of the elements of the railway line for the study of deformation processes as the basis of normative base of the track at the condition of railway safety. Methodology. To achieve the aim principles of the elasticity theory and wave propagation process in the description of the interaction between the track and rolling stock were used. Findings. The basic physical and structural conditions under which it is necessary to carry out the simulation of the life cycle of the elements of the railway line for the study of deformation processes were determined. The basic physical and structural principles of drawing the design schemes of railway track elements for the process assessment of the track deformation work were formulated. The decision correctness and the possibility of the problem solution are proved. Originality. The study of the track reliability questions motivates the development of new models, allow considering it for some developments. There is a need to identify the main physical and structural conditions for assembly design schemes based on assessment and prediction of possible track state changes during its operation. The paper presents the basic principles of physical and structural drafting design schemes of railway line items for which Huygens’ principle is implemented. This principle can be performed only when the four dimensional space: the volume changing over time is considered. Practical value. Analytical models applied in determining the parameters of strength and resistance lines, fully satisfy the task, but can not be used to determine the parameters of track reliability. One of the main impossibility factors of these models is quasidynamic approach. Therefore, as a rule, receive and examine not only dynamic process of a railway track, but also its consequences. Besides, these models are related to flat ones, and it also adds some complexity in results comparing with an experiment, as well as the process is not easy to distinguish the impact of volume in its limited parts. The use of numerical methods extend the posibilities, and it also make it impossible for the consideration of the dynamic process, as well as it is impossible to introduce processes, causing the reaction to stress load. Thus the basic physical and constructive approaches in modeling make it possible to consider the dynamic process of localized both in time and in space directly.