Science and Transport Progress

7-14

Authors: L. V. Amelina, M. M. Biliaiev

Purpose. Development fast calculating model which takes into account the meteorological parameters and buildings which are situated near the source of toxic chemical emission. Methodology. The developed model is based on the equation for potential flow and equation of pollutant dispersion. Equation of potential flow is used to compute wind pattern among buildings. To solve equation for potential flow Samarskii implicit difference scheme is used. The implicit change – triangle difference scheme is used to solve equation of mass transfer. Numerical integration is carried out using the rectangular difference grid. Method of porosity technique («markers method») is used to create the form of comprehensive computational region. Emission of ammonia is modeled using Delta function for point source. Findings. Developed 2D numerical model belongs to the class of «diagnostic models». This model takes into account the main physical factors affecting the process of dispersion of pollutants in the atmosphere. The model takes into account the influence of buildings on pollutant dispersion. On the basis of the developed numerical models a computational experiment was carried out to estimate the level of toxic chemical pollution in the case of unplanned ammonia release at ammonia pump station. Originality. Developed numerical model allows to calculate the 2D wind pattern among buildings and pollutant dispersion in the case unplanned ammonia release. Model allows to perform fast calculations of the atmosphere pollution. Practical value. The model can be used when developing the PLAS (Emergency Response Plan).

23-31

Authors: Y. M. Datsun

Purpose. Inspection and observation of the technical level of rail locomotive repair productions are conducted by the management team of the Department and the Locomotive division, audit sectors, expert groups within the production certification procedure. The faults revealed are fixed as linguistic expert reports which cannot assess their significance and identify priorities in terms of elimination. The paper aimed the development of methods for the conformance rating for locomotive repair production to legal requirements with conformance level determination. Methodology. Formalization of linguistic reports on the locomotive repair facility conformance takes into account the influence of a whole number of factors, their significance being determined by the expert assessment, formalized models of events when designing and analyzing the fault tree. In order to calculate the conformance, index the triple additive convolution with the weight coefficient is proposed. Investigation into interrelation between the integral index and the locomotive maintenance costs was conducted by methods of the correlation and regression analysis. Findings. The analysis of results of inspection and observation of the technical level of locomotive repair productions demonstrated a similar structure of expert reports on faults, which made it possible to present them as a vector. While transforming a multi-criterion problem into a single-criterion one of the most objective method, the weighted sum method, was applied. The conformance indices were calculated according to the results of observations on several locomotive repair productions. The correlation and regression analysis proved the influence of the conformance index of locomotive repair productions on locomotive maintenance overconsumption. Originality. The conformance rating methods for a technical level of locomotive repair productions based on linguistic expert reports which consider type of the fault detected, type of the technological process, type of the locomotive unit and type of the technical level of production have been designed. Practical value. Implementation of the methods designed will help undertake assessment of the faults detected, eliminate them according to the priority and invest more effectively in locomotive repair productions. The regressive equations obtained allow standardizing the conformance index and forecasting possible locomotive maintenance overconsumption by the results of inspection at repair productions.

45-55

Authors: О. A. Tereshchenko

Purpose. The article highlights development of the methodological basis for simulation the processes of cars accumulation in solving operational planning problems under conditions of initial information uncertainty for assessing the sustainability of the adopted planning scenario and calculating the associated technological risks. Methodology. The solution of the problem under investigation is based on the use of general scientific approaches, the apparatus of probability theory and the theory of fuzzy sets. To achieve this purpose, the factors influencing the entropy of operational plans are systematized. It is established that when planning the operational work of railway stations, sections and nodes, the most significant factors that cause uncertainty in the initial information are: a) external conditions with respect to the railway ground in question, expressed by the uncertainty of the timing of cars arrivals; b) external, hard-to-identify goals for the functioning of other participants in the logistics chain (primarily customers), expressed by the uncertainty of the completion time with the freight cars. These factors are suggested to be taken into account in automated planning through statistical analysis – the establishment and study of the remaining time (prediction errors). As a result, analytical dependencies are proposed for rational representation of the probability density functions of the time residual distribution in the form of point, piecewise-defined and continuous analytic models. The developed models of cars accumulation, the application of which depends on the identified states of the predicted incoming car flow to the accumulation system, are presented below. In addition, the last proposed model is a general case of models of accumulation processes with an arbitrary level of reliability of the initial information for any structure of the incoming flow of cars. In conclusion, a technique for estimating the results of simulation the cars accumulation was proposed to optimize the transportation process, depending on the chosen criterion. Findings. The developed methodology of simulation of cars accumulation process was reflected in the dynamic models created with the participation of the author and implemented on the Belarusian Railroad on the basis of IAS SMD CT. They are designed to provide operational planning of the transportation process on the basis of methods that allow assessing technological risks. Originality. The innovative component of the work is due to the expansion of existing models of the accumulation of cars for cases of uncertainty of the initial information. Thus, the earlier deterministic models are particular cases of the proposed model. Also, unlike existing ones, the technique allows to take into account the influence of random processes in a complex manner. Due to this, technological risks can be further assessed and the necessary regulatory measures can be implemented promptly. In general, the results obtained by modeling the proposed method allow to improve the quality of output solutions in the system of shift and daily operational planning, increasing the reliability of operational plans. Practical value. To date, there is a favorable opportunity to use the proposed methodology of modeling in existing in the railway transport systems of automated operational planning for operational work, including the optimization of local railways and the solution of a number of urgent tasks of train formation.

66-76

Authors: A. Y. Drubetskyi

Purpose. The article is aimed to develop a technique for calculating the magnetic characteristics of uncompensated traction electric motors (TEM) at any degree of attenuation of excitation based on the approximating expression for improved universal magnetic characteristics (UMC). It is also necessary to conduct an analysis of expressions for improved UMC with the aim of finding an expression that most fully satisfies the requirements for developing a technique for determining the inductive parameters of TEM. Methodology. It is necessary to determine the saturation coefficient for each degree of attenuation of the excitation for building the characteristics with the improved UMC. This can only be done analytically. To simplify the analytical finding of the saturation coefficient, the method based on solving a system of two equations is proposed, one of which is UMC itself, and the second one is a straight line whose angular coefficient is proportional to the saturation coefficient. Resulting values of the saturation coefficient for the excitation degrees β < 1 are essentially the coefficients of the shape of the magnetic characteristic. To get rid of the need to determine the coefficients of approximation each time in the calculation of characteristics a form of improved UMC is proposed, in which the magnetomotive force (MMF) of the excitation winding serves as the argument's role. Findings. Using the improved UMC it is possible to calculate the characteristics of uncompensated TEMs for any degree of attenuation of excitation. The accuracy of the calculation at β = 1 does not differ from that in the calculation for UMC, proposed by Prof. M. D. Nakhodkin. The same accuracy is preserved at excitation degrees that are different from unity. Originality. An analytical technique for calculating the magnetic (speed) characteristics of uncompensated TEM for any degree of attenuation with the help of an improved UMC is proposed. The analytical technique for determining the saturation coefficient for an improved UMC at any degree of attenuation of excitation is also proposed. Due to the introduction of an excitation winding as an argument, there is no need to determine the approximation coefficients for each specific TEM. Practical value. The developed methodology let calculate magnetic characteristics of uncompensated REMs for any degree of attenuation of excitation. On the basis of this technique, it is possible to develop a technique for determining the inductive parameters of the TEM, using the saturation coefficient of the machine as initial data.

92-101

Authors: A. F. Golovchuk

Purpose. The research paper involves solving of the following tasks: 1) refinement of the mathematical model for determining the traction and dynamic, fuel and economic, environmental indicators of mobile energy facilities; 2) methodology development of theoretical studies of automatic control systems, static and dynamic characteristics automotive-tractor diesel with a gas turbine supercharger and a mobile power facility. Methodology. The work studies the working processes of vehicles and machine-tractor aggregates by mathematical simulation and the development of algorithms and programs for the calculation of these processes in actual operational conditions. The system of equations has been developed for theoretical research. It describes a nonlinear mathematical model of the automatic control system of an automotive-tractor diesel rotating frequency. In addition to the differential equations of the first and second order, equations are used in mathematical simulation of working processes of traction vehicles. These equations describe experimental characteristics of an automatic regulator, a high-pressure fuel pump, a turbocharger and an engine, as well as moments of engine mechanical losses and an external load. Findings. The developed mathematical model allows determining the effectiveness of new design, operational and technological developments, as well as various measures in order to improve the fuel-economic and environmental performances of vehicles and machine-tractor aggregates in operating conditions. Originality. For the first time, the mathematical model "Tractor driver – machine-tractor aggregate – road (field)" was developed. It allows conducting research of transport tractor aggregates by driving cycles, taking into account the processes of starting and speeding up the mobile-power sources with gear shift. Practical value. In conditions of a protracted economic crisis, in the absence of the necessary equipment, instruments, combustible and lubrication materials, comparative research of mobile power sources can be carried out thanks to the developed mathematical models with corresponding algorithms and programs that are brought to practical use. For these computer programs State Intellectual Property Service of Ukraine issued Certificates on registration of copyright No. 49285, No. 49286, No. 49287 of May 22, 2013.

112-120

Authors: P. G. Anofriev

Purpose. The main purpose of experimental studies is to establish the adequacy of the developed mathematical models of machine fluctuations and the actual parameters of machine vibration. Almost all casting machines for the production of mill rolls have a unique design and performances. The additional aim of this work is to compare the vibration level of the casting machine with the requirements of the current vibration standards for new technological machines. Frequency analysis of the oscillations allows establishing defects in workmanship, errors of rotating parts installation and their influence on the dynamics of the machine. Methodology. Measurement of vibration parameters was performed on the moving parts of roller bearings of the machine. To measure the amplitudes of accelerations in three mutually perpendicular directions piezoelectric sensors with magnetic mount were used. Electrical signals from the sensors were recorded on magnetic tape. Further analysis of the oscillations was carried out and visualized using specialized frequency analyzer. The frequency analyzer implements the algorithm of fast Fourier transformation and/or integration of sensor input signal. After the first integration the data for plotting the vibration velocity spectrogram were obtained and as a result of the second integration there are the data of vibration displacements spectrogram of the machine supports. Findings. The results of experimental studies of centrifugal casting machine vibrations for the production of two-layer rolls were presented. There were obtained and analyzed the spectrograms of accelerations, velocities and displacements of moving parts of the upper and lower roller supports. The work of the machine is associated with the calculated values passing of critical frequencies and the short-term development of resonance oscillations of the rotor and roller bearings. Originality. For the first time the author obtained the frequency spectra of vibration of an industrial sample of a casting machine. The oscillations with frequencies that differ from the basic rotor frequency were detected. Practical value. Based on the results of the experiment, the actual vibration parameters of the machine in steady state when testing without die-casting the metal were determined. The adequacy of mathematical models of the dynamics of the machine and its industrial model was established. Using the method of one tone the coefficients of vibration velocity distortion of the rotor harmonic, indicating the nonlinear transformations in the system "rotor - bearings" were obtained. It was experimentally established that the vibration parameters of the machine are within the acceptable ranges, regulated by standards for vibroactive machines.

130-146

Authors: S. V. Myamlin, O. Lunys, L. O. Neduzha

Purpose. To determine the dynamic qualities of the main locomotives that characterize safety traffic along straight and curved track sections in the entire range of operational speeds, it is necessary to perform a whole range of studies. One of the necessary conditions for a qualitative improvement of the traction rolling stock of railways is the determination of the parameters of its running gears. Among the issues related to this problem, the important task is to determine the dynamic qualities of locomotives at the design stage, taking into account the selected technical solutions in the design of running gears. At the same time, special attention is paid to the connections of the body with bogie, in particular, using the inclined rods. Methodology. Mathematical modeling is carried out by the method of numerical integration of the equations of the mathematical model of locomotive spatial oscillations to determine the dynamic loading of the mainline locomotive using the software package "Dynamics of Rail Vihicles" ("DYNRAIL"). Findings. The research results show that in order to create a simple and reliable design of running gears, which will reduce maintenance and repair costs, will have low initial cost and operating costs for the whole life cycle, high traction force as close as possible to the ultimate force in traction, will make it possible to operate in the multiple traction mode, the designers and scientists should implement scientific and technical solutions. Originality. In accordance with researches authors formed general classification formation of body/bogie connections and the general classification of structures of inclined rod of locomotives. Practical value. Generalization of the results of theoretical, scientific-methodical, experimental studies aimed at further improving the running gears of long-distance locomotives of perspective structures is urgent in improving the rolling stock constructions. The research carried out by the authors concerning improvement of the structural features of the running gear elements of some types for modern mainline locomotives are of practical value and can be used in the development of traction rolling stock.

160-170

Authors: S. V. Kluchnik

Purpose. The staged connections of the beams of railway bridge track-way have the simplest design, but some design flaws result in numerous defects. The purpose of the given work is to research the actual stress-train state of the point of connection of the stringers with the floor beams on condition of their staged interposition. It is also necessary to determine possible effect of coupled work of deck beam grid and booms on their stress-strain state. Methodology. To reach the purpose of the study the testing of the existing bridge was conducted. To measure strains (stresses) in the span elements we used the strain gages glued to flange angles of stringers and floor beams and to fillets of lower flange angles of stringers in the points of their support on floor beams. To measure deflections of the truss, stringers and floor beams from static loads we used Aistov’s and Maksimov’s deflectometers, that were installed on lower boom in the middle of span 0-1, as well as on both stringers and floor beams in the middle of the span. Deflectometers were fastened to the span and, by wire communication, to the ground surface. Findings. Stress-strain state of the point of connection of the stringers with the floor beams on condition of their staged interposition was obtained and analyzed. Analysis indicates that, apart from vertical bending of the stringers and beams, there is a significant effect of horizontal bending of floor beams and their torsion, that occur due to the coupled work of track-way beams and top booms, both for P0 beam and for other beams. Originality. Research of stress-strain state of metal track-way staged beams while considering their coupled work with bearing trusses. Practical value. While testing the span under the train load, there are significant additional stresses from horizontal bending of floor beams and their torsion in the floor beam flanges. The appearance of these stresses is caused by inclusion of stringers into coupled work with top booms. Appearing flaws in stringers are caused by local stress concentration due to design features of staged track way.