Science and Transport Progress

18-29

Authors: E. P. Blohin, R. B. Granovskiy, E. M. Dzichkovskiy, A. E. Krivchikov, N. I. Granovskaya, A. Tsiyupa

Purpose. Experimental definition of values of the dynamic parameters characterizing traffic safety of the rail autobus in tangent and curved track sections and switches, and conformity check to their demands of normative documents. Methodology. Test methods are based on comparison of experimentally determined dynamic qualities of the autobus with their admitted values. As the parameters defining traffic safety, the numerical value of which is resulted further, are used the following ones: the derailment stability coefficient; vertical dynamics coefficients in the first and second steps of spring suspension; the frame forces; smoothness of movement. Determination of the derailment stability coefficient is performed by a known technique. Vertical dynamics coefficients in the each step of spring suspension are defined as the relation of dynamic vertical bending flexures to magnitudes of their static values corresponding to the set occupancy of the autobus. Findings. Coefficient values of the vertical dynamics of train carriages in the first and second steps of spring suspension, as well as the value of frame forces and parameters of movement smoothness did not exceed the admissible standard values, and was higher than the minimum admissible value. Originality. Values of the parameters characterizing dynamic qualities of new type of the rail autobus are obtained, and possibility of its operation on the main ways of the railways of Ukraine is shown. Practical value. Admissible speeds of the rail autobus traffic on various railway track sections are defined.

38-46

Authors: G. Vaychunas, G. Gelumbіtskas, L. P. Lingaytis

Purpose. To conduct a research and find out the causes of defects appearing on the wheel thread of freight locomotives 2М62 and SIEMENS ER20CF. Methodology. To find the ways to solve this problem comparing the locomotive designs and their operating conditions. Findings. After examining the nature of the wheel wear the main difference was found: in locomotives of the 2M62 line wears the wheel flange, and in the locomotives SIEMENS ER20CF – the tread surface. After installation on the 2M62 locomotive the lubrication system of flanges their wear rate significantly decreased. On the new freight locomotives SIEMENS ER20CF the flange lubrication systems of the wheel set have been already installed at the factory, however the wheel thread is wearing. As for locomotives 2M62, and on locomotives SIEMENS ER20CF most wear profile skating wheels of the first wheel set. On both locomotive lines the 2М62 and the SIEMENS ER20CF the tread profile of the first wheel set most of all is subject to the wear. After reaching the 170 000 km run, the tread surface of some wheels begins to crumble. There was a suspicion that the reason for crumb formation of the wheel surface may be insufficient or excessive wheel hardness or its chemical composition. In order to confirm or deny this suspicion the following studies were conducted: the examination of the rim surface, the study of the wheel metal hardness and the document analysis of the wheel production and their comparison with the results of wheel hardness measurement. Practical value. The technical condition of locomotives is one of the bases of safety and reliability of the rolling stock. The reduction of the wheel wear significantly reduces the operating costs of railway transport. After study completion it was found that there was no evidence to suggest that the ratio of the wheel-rail hardness could be the cause of the wheel surface crumbling.

56-62

Authors: V. D. Petrenko, D. O. Yampolskiy, I. O. Sviatko

Purpose. In transport engineering structures design, the primary task is to determine the parameters of foundation soil and nuances of its work under loads. It is very important to determine the parameters of shear resistance and the parameters, determining the development of deep deformations in foundation soils, while calculating the soil subgrade - upper track structure interaction. Search for generalized numerical modeling methods of embankment foundation soil work that include not only the analysis of the foundation stress state but also of its deformed one. Methodology. The analysis of existing modern and classical methods of numerical simulation of soil samples under static load was made. Findings. According to traditional methods of analysis of ground masses work, limitation and the qualitative estimation of subgrade deformations is possible only indirectly, through the estimation of stress and comparison of received values with the boundary ones. Originality. A new computational model was proposed in which it will be applied not only classical approach analysis of the soil subgrade stress state, but deformed state will be also taken into account. Practical value. The analysis showed that for accurate analysis of ground masses work it is necessary to develop a generalized methodology for analyzing of the rolling stock - railway subgrade interaction, which will use not only the classical approach of analyzing the soil subgrade stress state, but also take into account its deformed one.

73-82

Authors: I. A. Vakulenko, Yu. L. Nadezhdin, V. A. Sokirko, I. P. Volchok, A. A. Mitiaev

Purpose. Explanation of the redistribution effect of residual strengthes after electric pulse treatment of ark welding seam of the aluminum alloy. Methodology. Alloy on the basis of aluminium of АК8М3 type served as the research material. As a result of mechanical treatment of the ingots after alloy crystallization the plates with 10 mm thickness were obtained. After edge preparation the elements, which are being connected were butt welded using the technology of semiautomatic argon arc welding by the electrode with a diameter of 3 mm of AK-5 alloy. Metal structure of the welded joint was examined under the light microscope at a magnification of 200 and under the scanning electronic microscope «JSM-6360 LA». The Rockwell hardness (HRF) was used as a strength characteristic of alloy. Hardness measuring of the phase constituents (microhardness) was carried out using the device PМТ-3, with the indenter loadings 5 and 10 g. The crystalline structure parameters of alloy (dislocation density, second kind of the crystalline grid distortion and the scale of coherent scattering regions) were determined using the methods of X-ray structural analysis. Electric pulse treatment (ET) was carried out on the special equipment in the conditions of the DS enterprise using two modes A and В. Findings. On the basis of researches the previously obtained microhardness redistribution effect in the area of welded connection after ET was confirmed. As a result of use of the indicated treatment it was determined not only the reduction of microhardness gradient but also the simultaneous hardening effect in the certain thermal affected areas near the welding seam. During study of chemical composition of phase constituents it was discovered, that the structural changes of alloy as a result of ET first of all are caused by the redistribution of chemical elements, which form the connections themselves. By the nature of the influence the indicated treatment can be comparable with the thermal softening technologies of metallic materials. Originality. The observed structural changes of alloy and related to them microhardness change in the areas near the welding seam after ET are conditioned by both the change of morphology of structural constituents and the redistribution of chemical elements. In case of invariability of chemical elements correlation in the phase constituents of alloy the reduction effect of gradient microhardness should be far less. Practical value. In practice, the negative effect of the wares embrittlement made using the casting technologies, excluding the pressure casting and quite difficult selection of chemical composition of alloy can be significantly reduced during the treatment of alloy with electric pulses.

90-98

Authors: V. N. Pakhomovа, L. V. Stribulevich

Purpose. To study the characteristics of the local network with the marker method of access to the bus its modified simulation model was developed. Methodology. Defining characteristics of the network is carried out on the developed simulation model, which is based on the state diagram-layer network station with the mechanism of processing priorities, both in steady state and in the performance of control procedures: the initiation of a logical ring, the entrance and exit of the station network with a logical ring. Findings. A simulation model, on the basis of which can be obtained the dependencies of the application the maximum waiting time in the queue for different classes of access, and the reaction time usable bandwidth on the data rate, the number of network stations, the generation rate applications, the number of frames transmitted per token holding time, frame length was developed. Originality. The technique of network simulation reflecting its work in the steady condition and during the control procedures, the mechanism of priority ranking and handling was proposed. Practical value. Defining network characteristics in the real-time systems on railway transport based on the developed simulation model.

111-117

Authors: N. V. Bezrukavyy

Purpose. Taking into account the traffic safety priority on the railway transport the search of factors promoting increase of derailment stability coefficient is an actual task. Purpose of the paper is the influence researches of the high-frequency vibrations on the train traffic safety parameter. In this case the special form of the wheel rim, at which its rigidity changes according to the harmonious law, was considered as a source of vibrations. Methodology. For the analysis of the vibration influence on the change of friction coefficient values the methods of so called vibrational mechanics were used. For determination of vibration amplitudes through moving the wheel flange points the finite-elements method was also used in the paper. Findings. During calculations it was established that the derailment stability coefficient to a great extent depends on the friction coefficient between wheel and rail. The paper shows that the friction coefficient in turn is influenced by the high-frequency vibrations. The form of the wheel rim was considered as a vibration source and the parameters characterizing vibration were calculated. It was given the quantitative estimation of the friction coefficient change under the vibration influence. It was also scientifically based the high-frequency vibration influence on the derailment stability coefficient. Originality. The paper proved the possibility of high-frequency vibration influence on the derailment stability coefficient. The studies theoretically substantiated the traffic safety increase in the presence of vibrations in the contact area of the wheel flange with the rail caused by special form of the wheel disc. Practical value. It is shown that the use of undulating wheel disc form do not constitute a threat to the traffic safety, and the availability of high-frequency vibration can reduce the derailment probability.

127-134

Authors: R. Sh. Іsanov

Purpose. Investigation of the jet stream mechanism during the high-speed passenger train flow around. On the basis of theoretical studies to determine the distribution of air flow velocity field, the pressure on the upper layer of the double layer air current, the pressure at the boundary of both layers of double-layer air current. Methodology. To solve the problem on the top layer of air current the Zhukovsky method and the method of theory of ideal incompressible fluid jets was applied. Then to solve the boundary layer equations the pressure at the boundary of both layers was determined, the Navier - Stokes equation, which takes into account the influence of the top layer on the bottom layer was set up. Airflow in the upper region is a potential, stationary; the air in the vicinity is considered as the compressible one. Findings. The distribution of the velocity field for both layers of air current was obtained. The pressure on the upper layer of the double layer air flow was defined. Originality. The problem of a double layer air current formed by the high-speed train movement consisting of the boundary layer above the car surfaces and the air current with no viscosity was studied for the first time. Practical value. The problem under study is used to provide the safety of high-speed train traffic.

145-152

Authors: A. V. Rаdkеvich, I. A. Arutyunyan

Purpose. Development of theoretic and methodological approaches and scientific and practical recommendations concerning the management of the material flows of building complex. Methodology. Research includes analysis of existing scientific works concerning the problems of management of the construction development programs taking into account logistization on the enterprises of different branches related to the building complex. Experience generalization of administrative decision making in the process of production preparation, in particular the motion of material flows management of building resources and information flows (which accompany building resources), systematization of experience, logic analysis, design and system processing of information. Findings. Results give the building organization management an opportunity to estimate the material and technical support of the building objects according to the terms of building, technology of building processes, as well as to into account the minimization of expenses. Originality. Originality lies in the fact that the theoretical and methodological management foundations of the logistic system formation in the programs of building complex development are formulated on the basis of organization methodology development, planning and management from the point of view of the only system positions. Practical value. The contribution to the decision of the number of complex organizational and economic problems accompanied by the problems of building development is provided due to the increase of management efficiency of the material flows of building complex.