Science and Transport Progress

7-12

Authors: E. N. Shyrokova

Purpose. The observed tendencies in the development of the national economy require stable implementation of planned reforms in the sphere of industrial and economic activities of the railway transport in the strategic railway branch. At the same time the issue of resistance elimination to changes that innovative solutions may cause is topical. To study the subject matter of resistance manifestation to implementable changes and search for solutions on the problem in question as well. Methodology. Methodology in an article is based on the use of consistent methodological technique. Findings. It contains the author’s point of view on necessity of taking changes resistance into account during restructuring and further reformation. Emphasized is the need for careful planning of changes and current detection of obstacles that inevitably, for a variety of reasons, arise. Originality. The causes of resistance to changes from different points of view were identified in this paper. Their classification was made and some advice for manifestation leveling of resistance to changes was offered. Practical value. The rational application of measures for resistance leveling to the introduced measures will provide not only high-quality and fast implementation of the reform program, but also its implementation with minimum time and finance losses. That is an important factor in competitiveness increase of railways under unstable economic development.

22-28

Authors: D. M. Kozachenko

Purpose. The article aims to create a mathematical model of the railway station functioning for the solving of problems of station technology development on the plan-schedule basis. Methodology. The methods of graph theory and object-oriented analysis are used as research methods. The model of the station activity plan-schedule includes a model of technical equipment of the station (plan-schedule net) and a model of the station functioning , which are formalized on the basis of parametric graphs. Findings. The presented model is implemented as an application to the graphics package AutoCAD. The software is developed in Visual LISP and Visual Basic. Taking into account that the construction of the plan-schedule is mostly a traditional process of adding, deleting, and modifying of icons, the developed interface is intuitively understandable for a technologist and practically does not require additional training. Originality. A mathematical model was created on the basis of the theory of graphs and object-oriented analysis in order to evaluate the technical and process of railway stations indicators; it is focused on solving problems of technology development of their work. Practical value. The proposed mathematical model is implemented as an application to the graphics package of AutoCAD. The presence of a mathematical model allows carrying out an automatic analysis of the plan-schedule and, thereby, reducing the period of its creation more than twice.

36-43

Authors: I. A. Vakulenko, S. V. Proydak, N. N. Grischenko

Purpose. The purpose of work is the possibility estimation of аthermic technologies use of cold-deformed metal softening for elements of railway car body and wheel. Methodology. The material for research is the carbon steel of the wheel rim fragment containing 0.55%С, 0.74%Mn, 0.33%Si, and the steel 20. The wheel steel is studied after heat strengthening and cold work after operation. Steel 20 is studied after plastic cold work by rolling. Electric pulse treatment (ET) is carried out on the special equipment. As the property of metal strength the Vickers hardness number is used. The microstructure research is carried out using the light and electronic microscope. Findings. During operation of the rolling stock elements with different strength level origin of damages on metallic surfaces is caused by a simultaneous load action. Taking into account that forming of breakdown sites is largely determined by the state of metal volumes nearby the places of maximal active voltages, the technology development of defect accumulation slowdown or the level of active voltages development allow one to prolong the operating term of rolling stock elements. After electric pulse treatment of the wheel rim fragment the regular changes of metal internal structure corresponded to the hardness changes. The hardness of low carbon steel increases proportional to the increase of the level of cold work by rolling. Alternating bending of the cold-deformed flat is accompanied by strength decrease, which is caused by the metal substructure changes. Originality. The softening process of the cold-worked steel is accompanied by substructure changes, which to a greater extent correspond to the hardening development from the plastic cold-work: dispersion of the dislocation cellular structure, formation of the new sub boundaries and displacement of the formed sub boundaries. Practical value. Introduction of electric pulse treatment in the conditions of railway depots repair base allow one to attain the required level of softening of the cold-worked steel on the wheel thread of railway wheel without heating of metal. The given treatment reduces the metal hardness and prolongs the term of incisors use during the renovation of the rolling profile of the railway wheel

53-59

Authors: O. V. Lyutova

Purpose. To study the influence of metallurgical factors of production on casting properties of secondary aluminum alloy АК9М2. Methodology. For the experimental melts shaving amount in a charge, iron content and the quantity of modifier additive were chosen as independent variables. The components of modifier were being changed in the intervals of 25…40 % Na2CO3, 12…20 % SiC, 3…8 % Ti, the other – S. The microstructure of alloys was investigated under a light microscope, using the method of quantitative metallography. Influence analysis of certain parameters of alloys was conducted by mathematical statistics methods. The influence of shaving additions, iron and modifier amount on liquidity and porosity of the resulting alloys was studied. Findings. The paper shows that the increase of shaving content in the charge from 1 to 19 % and iron content in alloy from 0.66 to 2.34 % resulted in the decline of alloy liquidity on 30…35 %. Simultaneously the linear shrinkage reduction for 18…20 % and the porosity increase from 0.5 to 2.5 points were observed. The presented changes of alloy casting properties are conditioned by the amount of intermetallic phases of unfavorable form and its capacity for aeration. Increase of modifier additive from 0.02 to 0.15 % resulted in the liquidity increase on 10…15 %, the increase of linear shrinkage on 30…35 % and porosity decline from 2.5 to 0.5 points. At the same time a change of form of intermetallic phases and increase of their evenness were observed. Originality. The increase of iron concentration in silumin composition is accompanied by the decline of its liquidity. Thus, the rate of decline of alloy liquidity is proportional to the amount of dissolved iron. The character of iron influence is caused by formation of high temperature intermetallic compounds of the type Al3Fe, Al5SiFe, which promote the metal viscidity. Practical value. Practical use of the obtained scientific results would develop the technical solutions oriented to the quality indicator increase of silumin alloy.

67-73

Authors: J. Tatarko, M. Kushnir, I. Markova, T. Ivchenko

Purpose. Stabilizing of chemical composition and properties, decrease of detrimental impurities concentrations, amount of nonmetallics, grinding down of grain of the R7 wheeled steel by treatment of multicomponent modifiers. Methodology. Probed chemical composition and mechanical properties in accordance with UIC 812-3 and EN 13262 serial melting steel R7 and treated a multicomponent deoxidizers-modifiers are researched. Processing of data is conducted by a regressive-cross-correlation analysis. Findings. Influence of operations of out-of-furnace treatment is set on detrimental impurities concentration. Using of complex modifiers has reduced the concentration of sulfur most effectively. It is shown that in the modified melting variation of both basic alloying elements and admixtures has decreased, homogeneity and dispersion of structure have increased, what mechanical properties of wheels were stabilized due to. Originality. Influence was first set each of the stages of out-of-furnace treatment steel R7 on the detrimental impurities concentration, micro hardness, structure of hard-tempered tests. Dependences of mechanical characteristics were got of the detrimental impurities concentrations. Practical value. By treatment of multicomponent deoxidizers-modifiers, stabilization of chemical composition, sulfur concentration reducing, nonmetallic inclusions amount, grain refining and improving the homogeneity of the structure are achieved, this led to stabilizing and increase of mechanical properties level. It is shown the efficiency of multicomponent deoxidizers-modifiers usage in order to improve quality of steel R7 and reliability of wheels made of it.

82-92

Authors: O. V. Grachyov

Purpose. The fractional composition information recovery is one of the main problems of coal enrichment, as the quality of its solving directly affects at all the processes of coal preparation plant. Due to the fact that this model has a stochastic nature, as well as the method of identifying the model parameters, a promising direction for further research is to analyze the effect of errors in the determination of model parameters on its stability. This requires an analysis of the experimental data to assess changes effect of weight flatness functions in boundary density and ash content on model description stability of coal fractional composition. Methodology. The problem is solved by methods of mathematical statistics and stochastic processes, and optimization methods. Findings. Analysis carried out of changes effect of weight flatness functions in boundary density and ash content on model description stability of coal fractional composition has shown the following. In a small neighborhood of the parameters a0, a1, b0 and b1 assessment of the relative error in determining the output of narrow fractions and assessment of the relative error in determining the average ash content of narrow fractions is less than 0.05. Practical value. The analysis showed that in a small neighborhood of the optimal values of the model parameters describing coal fractional composition an error in determining the composition of the coal output and an average ash content is not very sensitive to changes in parameter values and do not exceed the error of obtaining experimental data.

103-110

Authors: V. N. Pakhomovа

Purpose. Search for new options of the transition from Ethernet technology. Methodology. Physical structuring of the Fast Ethernet network based on hubs and logical structuring of Fast Ethernet network using commutators. Organization of VLAN based on ports grouping and in accordance with the standard IEEE 802 .1Q. Findings. The options for improving of the Ethernet network are proposed. According to the Fast Ethernet and VLAN technologies on the simulation models in packages NetCraker and Cisco Packet Traker respectively. Origiality. The technique of designing of local area network using the VLAN technology is proposed. Practical value.Each of the options of "Dniprozaliznychproekt" network improving has its advantages. Transition from the Ethernet to Fast Ethernet technology is simple and economical, it requires only one commutator, when the VLAN organization requires at least two. VLAN technology, however, has the following advantages: reducing the load on the network, isolation of the broadcast traffic, change of the logical network structure without changing its physical structure, improving the network security. The transition from Ethernet to the VLAN technology allows you to separate the physical topology from the logical one, and the format of the ÌEEE 802.1Q standard frames allows you to simplify the process of virtual networks implementation to enterprises.

119-124

Authors: L. A. Manashkin, S. V. Myamlin

Purpose. There is a need of wear process modeling in the wheel-rail system. This is related to the fact that the wear processes in this system are absolutely different in the initial and final stages. The profile change of rail and, especially, of the wheels caused by the wear significantly affects the rolling stock dynamics, traffic safety and the resource of the wheels and rails. Wear modeling and the traffic safety evaluation requires the accounting of the low frequency component forces (including the modeling of transitional areas) affecting the wheel on the side of the rail and carriage in motion of rolling stock, so the statistical analysis is not possible. Methodology. The method of mathematical modeling of the wheel set and the rail interaction was used during the research conducting. Findings. As a result of the modeling of the wheel set motion on the rail track, the mathematic model with 19 freedom degrees was obtained. This model takes into account the axle torque and studies wheels constructions as the components of the mechanical systems, consisting of a hub and tire. Originality. The mathematic model allows evaluating the wear degree of the wheels and rails when using on the rolling stock not only all-metal wheel sets, but also compound ones with the use of spring wheels and independent rotation of semi-axes with the wheels. Practical value. The development of the improved mathematical model of freight car wheel set motion with differential rotation of the wheels and compound axles allows studying the wear processes of wheels and rails.