Showing papers in "Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport in 2016"

Atmosphere protection in case of emergency during transportation of dangerous cargo

Abstract: Purpose. The paper highlights the d evelopment of numerical models for prediction of atmospheric pollution in case of burning of the solid rocket propellant in a railway car, situated near the building on railway territory. These models can be used in predicting the effectiveness of neutralization upon the atmosphere protection for this type of accidents. Methodology. To solve this problem the numerical models based on the use of Navier-Stokes equations, to determine the velocity field of the wind flow near cars and buildings, and contaminants-transfer equations in the atmosphere were developed. For the numerical integration of pollutant transport equation was used implicit «change – triangle» difference scheme. When constructing a difference scheme physical and geometric cleavage of the transfer equation is carried out in four steps. Unknown value of pollutant concentration at each step of cleavage is determined by the explicit scheme – the method of «point-to-point computation». For the numerical integration of the Navier-Stokes equations are used implicit difference schemes. When carrying out computing experiment also takes into account: the velocity profile of wind flow; interaction between the building and the wind flow and flame jet of solid rocket propellant; the presence of a railroad car; inside which there is a source of pollution; instability of pollutant emissions. On the basis of constructed numerical models was performed the computer experiment for assessing the level of air pollution at dangerous cargo rail transportation in case of emergency at railway territory.The application calculations for the timely combustion products neutralization of solid rocket propellant were carried out. Findings. The numerical models that let promptly calculate air contamination in case of emergency during solid rocket propellant transportation, as well as calculate the rational parameters of pollutant neutralization process were developed by the researcher. These models can be used for routine calculations of various accident scenarios simulation. Originality. Numerical models were developed; they take into account significant factors, influencing the pollutant dispersion process in the atmosphere. On their base a pollutant neutralization method was offered in emergency situations on the railway transport. Practical value. Efficient numerical models, so called «diagnostic models» were considered for the rapid calculation of the air pollution level and air protection technology in emergency situations, in particular, in the case of railway transportation the solid rocket propellant.

Determination the permissible forces in assessing the lift resistant factor of freight cars in trains

Abstract: Цель . В аналитическом исследовании рассматриваются: 1) связь между продольной силой, действую-щей на вагон в составе поезда; 2) боковые и вертикальные силы взаимодействия в зоне контакта колеса и рельса; 3) динамические показатели вагонов с величиной коэффициента запаса устойчивости от выжимания; 4) получение зависимостей между ними. Методика . Исследование проводилось аналитическим методом оценки устойчивости грузового вагона при движении с различными скоростями по прямым и кривым участкам пути. Результаты . В процессе исследования движения поезда, при расследовании транспортных событий, а также во время выполнения учебного задания на тренажере машиниста для оценки его действий используются величины продольных сил в межвагонных соединениях. Получено выражение для вычисления значения продольной сжимающей силы, действующей на вагон, при которой величина коэффициента запаса устойчивости от выжимания равна допустимому значению (критическая сила). Для оценки влияния на величину продольной силы скорости движения, коэффициентов вертикальной и горизонтальной динамики, а также ветровой нагрузки на боковую поверхность кузова вагона приведены результаты расчетов движения порожнего полувагона модели № 12-532 по кривой радиусом 250 м с возвышением 150 мм и поперечным разбегом рамы кузова вагона относительно оси пути в направляющем сечении в 50 мм. Научная новизна . В данном исследовании приведена методика определения продольной сжимающей силы, несколько отличающаяся от общепринятой. Также оценивается влияние на неё скорости движения подвижного состава, коэффициентов вертикальной и горизонтальной динамики и ветровой нагрузки на боковую поверхность кузова вагона. Практическая значимость . Авторами разработаны предложения по уточнению существующих методик определения значения продольной сжимающей силы, действующей на вагон, при которой величина коэффициента запаса устойчивости от выжимания будет равна допустимому значению. Это позволит оценивать устойчивость каждого вагона поезда от выжимания непосредственно во время моделирования его движения. Наиболее эффективно использовать эту методику можно в тренажерах, предназначенных для обучения машинистов безопасным способам вождения поездов, и при расследовании причин схода вагонов.

Methodological fundamentals of determination of unpowered rolling stock maintenance characteristics

Abstract: Цель . Научная работа предусматривает: 1) подтверждение как заявленных технических характеристик вагонов и их модификаций, так и показателей безотказной работы в течение межремонтного времени или наработки; 2) усовершенствование методологических подходов оценки эксплуатационных характеристик новой и модернизируемой техники железнодорожного транспорта на примере несамоходного подвижного состава, а именно − железнодорожных грузовых вагонов; 3) решение научно-прикладной проблемы по оценке эксплуатационных характеристик новой и модернизируемой железнодорожной техники. Методика . Рассмотрены основные методологические подходы к оценке эксплуатационных характеристик на примере несамоходного подвижного состава, а именно − железнодорожных грузовых вагонов. Проводится анализ безотказности вагона, который рассматривается как сложная механическая система, где все элементы системы соединены последовательно, при этом каждый из элементов включает m последовательно соединённых деталей. Отказ каждой расчетной части приведет к отказу вагона. Таким образом, вагон является системой без резервирования. Результаты . Усовершенствована методика оценки эксплуатационных характеристик грузовых вагонов в подконтрольной эксплуатации с учетом особенностей вагонов нового поколения. Уточнены: длительность проведения испытаний, периодичность осмотра контрольной группы вагонов, контролируемые параметры вагона, причины досрочного прекращения подконтрольной эксплуатации. Выявленные в процессе подконтрольной эксплуатации отказы разделены по их характеру. Научная новизна . Авторами предложена методика оценки эксплуатационных характеристик железнодорожной техники в опытной эксплуатации на примере грузовых вагонов нового поколения. Практическая значимость . Результаты работы позволяют оценить эксплуатационные характеристики новой и модернизируемой техники железнодорожного транспорта при проведении эксплуатационных испытаний

Controlling the speed of rolling cuts in conditions of reduction of brake power of car retarders

Abstract: Purpose. The study aims to develop the requirements for organization of the marshalling process in the conditions when the power of retarder positions is less than the nominal one. Methodology. The research is carried out using the train traffic safety theory and mathematical modelling of hump processes. Findings . The current technical standard documents regulating the operational performance of humps do not contain direct instructions on how to proceed in the event of brake power loss by car retarders, thus creating threats to the traffic safety. This problem is quite acute for the Ukrainian railways in connection with a chronic shortage of funds for the repair and renewal of technical equipment, including the humps. At the same time, a significant drop in the volume of work leads to the fact that the hump required processing capacity can be provided in case of partial failure of retarders as well. Herewith the most important task is to ensure the breaking-up safety in conditions of parametric failures of retarders. The analysis of dangerous situations, the occurrence of which is possible at humps, as well as the modelling of cut rolling, allowed establishing the connection between the value of retarder tire pressing force on the car wheels and the breaking-up modes, providing the safety of marshalling process. The paper sets the application areas of such measures as the breaking-up speed reduction, breaking-up termination, the use of additional braking by block hangers. Originality. The originality of the work lies in the fact that it first obtained the complex of dependencies that determine the performance requirements for the power of hump retarders and allow the staff to enter the appropriate limits for breaking-up modes to ensure the marshalling process safety. Practical value. The results of the research can be used to supplement the «Instruction on the maintenance of facilities of mechanized and automated humps» in order to determine the limits of breaking-up modes when detecting the reduction of retarder power below the nominal one.

Numerical simulation of toxic chemical dispersion after accident at railway

Abstract: Purpose. This research focuses on the development of an applied numerical model to calculate the dynamics of atmospheric pollution in the emission of dangerous chemical substances in the event of transportation by railway. Methodology. For the numerical simulation of transport process of the dangerous chemical substance in the atmosphere the equation of convection-diffusion pollutant transport is used. This equation takes into account the effect of wind, atmospheric diffusion, the power of emission source, as well as the movement of the source of emission (depressurized tank) on the process of pollutant dispersion. When carrying out computing experiment one also takes into account the profile of the speed of the wind flow. For the numerical integration of pollutant transport in the atmosphere implicit finite-difference splitting scheme is used. The numerical calculation is divided into four steps of splitting and at each step of splitting the unknown value of the concentration of hazardous substance is determined by the explicit running account scheme. On the basis of the numerical model it was created the code using the algorithmic language FORTRAN. One conducted the computational experiments to assess the level of air pollution near the railway station «Illarionovo» in the event of a possible accident during transportation of ammonia. Findings. The proposed model allows you to quickly calculate the air pollution after the emission of chemically hazardous substance, taking into account the motion of the emission source. The model makes it possible to determine the size of the land surface pollution zones and the amount of pollutants deposited on a specific area. Using the developed numerical model it was estimated the environmental damage near the railway station «Illarionovo». Originality. One can use the numerical model to calculate the size and intensity of the chemical contamination zones after accidents on transport. Practical value. The numerical model, developed by authors, can be used to estimate the size and intensity of the chemical contamination zones during emergency on transport. The developed numerical model solves the problem of assessing the impact of emergency emission of ammonia near the railway station «Illarionovo».

Modernization as a way to improve the use of universal cars

Abstract: Purpose. The main design requirements of the modernized cars are those allowing reduction of operating costs and improvement of economic efficiency of their use. Due to the relevance of this subject the work presents the complex of conducted research, which will allow in prospect to use the universal flatcar, converted according to the Technical specifications TU 3182-065-71390252-2911 for container service. The research includes: evaluation of strength, fatigue safety of the design elements and conformity assessment of the strength characteristics of the modernized flatcar elements to the regulatory documents. Methodology. The analysis covers the use of specialized and universal rolling stock for transportation of containers, as well as the issues of modernization of universal cars. The strength of the flatcar bearing structure is evaluated based on the complex of numerical and experimental studies. The experimental part includes the static, repair load and impact tests. The car strength qualities and the fatigue safety are evaluated on the basis of calculated and experimental data. Findings. The conducted static, repair load and impact tests, given the quasi-static longitudinal forces, allowed the evaluation of the car structure strength according to the regulatory documents. The calculated and experimental data make it possible to assess the fatigue safety of structural elements. The present work is completed by obtaining the results that allow performing reasonable re-equipment of universal flatcars with baseplates with fitting stops to fasten the containers. Originality. The results of calculated and experimental studies showed that the modernized flatcars meet the conditions of strength and have sufficient fatigue safety factor. This makes it possible to recommend the re-equipment of universal flatcars for all car-repair enterprises that submitted the prototypes. Practical value. The complex of works was conducted that demonstrated the possibility of re-equipment of universal flatcars for the transportation of large containers. Part of the car fleet, kept in reserve, with little material costs can be transferred to the operational fleet. The modernization – re-equipment of universal flatcars with stationary specialized devices will increase the car usability coefficient.

Dependence of air spring parameters on throttle resistance

Abstract: Purpose. In this paper it is necessary to conduct: 1) research and analyse the influence of throttle element pneumatic resistance on elastic and damping parameters of air spring; 2) to obtain the dependence of air spring parameters on throttle element pneumatic resistance value. Methodology. The work presents the elaborated model of the air spring as a dynamic system with three phase coordinates (cylinder pressure, auxiliary reservoir pressure, cylinder air mass). Stiffness and viscosity coefficients were determined on the basis of system response to harmonic kinematic disturbance. The data for the analysis are obtained by changing the capacity of the connecting element and the law of pressure variation between the reservoir and the cylinder. The viscosity coefficient is regarded as the viscosity ratio of the hydraulic damper, which for one oscillation cycle consumes the same energy as the air spring. The process of air condition change inside the cylinder (reservoir) is considered to be adiabatic; the mass air flow through the connecting element depends on the pressure difference . Findings. We obtained the curves for spring viscosity and stiffness coefficients dependence on the throttle resistance at three different laws, linking airflow through the cylinder with the pressure difference in cylinder and reservoir. At both maximum and minimum limiting resistance values the spring viscosity tends to zero, reaching its peak in the mean resistance values. Stiffness increases monotonically with increasing resistance, tends to the limit corresponding to the absence of an auxiliary reservoir (at high resistance) and the increase in cylinder volume by the reservoir volume (at low resistance). Originality . The designed scheme allows determining the optimal parameters of elastic and damping properties of the pneumatic system as function of the throttle element air resistance. Practical value . The ability to predict the parameters of elastic and damping properties of the pneumatic system as function of the throttle element air resistance will improve the running performance of carriages, the comfort of passenger transportation and reduce the wear of the rolling stock and the track caused by interaction of carriage and rails.

Application of apm winmachine software for design and calculations in mechanical engineering

Abstract: Purpose . To conduct the research at all stages of design, development, operation, residual operation life determination, namely, preliminary study, action principle choice, design of draft and technical projects, their optimization, preparation of design documentation and control information for automated production, comprehensive engineering analysis, it is required to use the latest computer technologies. Their use can not only present data and information in some way, but also gives the opportunity to effectively and directly interact with the information object that is created or demonstrated. Methodology . To perform engineering calculations associated with the analysis of the strength of machines, mechanisms, constructions one uses both analytical and numerical methods in practice. The most common method for analysing the stress-strain state of object models, obtaining their dynamic and stability characteristics at constant and variable modes of external load is the finite element method, which is implemented in many famous and widespread software products, providing strength calculation of models of machines, mechanisms and structures. Findings. The use of modern software for designing machine parts and various types of their joints and for strength analysis of structures is justified. Colour charts for distribution of stresses, displacement, internal efforts, safety factor and others allow accurate and quick identification of the most dangerous places in the structure. The program also provides an opportunity to «look» inside the elements and see the resulting distribution of internal force factors. Originality. The paper considered the aspects, which are unexplored at present, associated with the current state and prospects of development of industrial production, the use of software package for design and calculations in the mechanical industry. The result of the work is the justification of software application for solving problems that are aimed at using research findings for various practical tasks in specific fields of mechanical engineering. Practical value. Compared with other software systems, popularity of the considered one is explained by easy mastering of the system, quick implementation both in training and in production process The organizational structure, «friendly» graphical interface and accessible language make learning and use of the program very convenient. These and other factors actually reduce the time for project implementation, emphasize the relevance and the practical importance of the software system, which is appreciated by its users.

About the issue of carbides fe3c and fe7c3 formation in high-chromium cast irons

Abstract: Purpose. This article a nalyzes the formation conditions, transformation and systematization of carbide phases formed in the system Fe – C – Cr. Methodology. Conversion of the elements’ content from mass % into atomic % and vice versa was carried out using standard methods. In order to identify the structural components and etching of carbides the Marble etchant was applied. Cast iron 300Х28Н2 in cast state without heat treatment and after isothermal holding at 1050 °С during 4.5 hours with further normalization was studied. Findings. Isothermal state diagrams of the Fe–C–Cr system don’t take into account the existence of Fe 7 C 3 carbide alloyed with chromium. But there is evidence of the existence of chromic carbides containing 24…37.6 % of chromium, which exceeds its maximum solubility in cementite, but is not enough to form Cr 7 C 3 . Analysis of chromium and carbon content in carbide phases which are formed in high-chromium cast irons allowed to substantiate the formation of Fe 7 С 3 carbide, stabilized with chromium. Assessment of the carbide phase by chemical composition in mass percent doesn’t allow determining the main carbide-forming element with sufficient accuracy. It is shown that with the increase of chromium concentration in carbides, mass content of carbon increases. Areas of existence of carbides of different types depending on carbon and chromium content in them were determined. Maximum content of chromium in the carbide (Fe, Cr) 7 C 3 is 44.0 %. Allocation of alloyed cementite occurs on the present carbides Ме 7 C 3 or grain boundaries, and with the increase of cooling rate – in the grain volume. This process is thermodynamically inevitable due to the decrease of carbon solubility in ferrite or austenite at temperatures when chromium diffusion is impeded, and only carbon diffusion is possible. At high chromium concentrations carbide Fe 7 C 3 is formed, which transforms into Cr 7 C 3 carbide as chromium diffusion takes place. Originality. The model of laminated structure of carbides, formed out of the liquid phase in the system Fe–C–Cr was built. The identification of the carbide phase based on the elements’ concentration in atomic percent was suggested. The model of the change of carbon content in carbides of different types depending on chromium concentration was built. Practical value. The suggested system of carbide classification and their structural model allows optimizing the cast irons’ composition and heat treatment modes for different exploitation conditions.

Types of steel and concrete composite cable space frames

Abstract: Purpose. Modern terms of the construction generate the need to find new structures, including roof systems that would meet modern requirements. An important aspect in finding constructive solutions for new structures is the use of reliable and advanced materials. Considering this, the decision to develop the new space structures to a wide implementation in practice of domestic and foreign construction are relevant and perspective direction of building structures development. Methodology. Given the results of previously conducted theoretical research of existing types of space roof structures find promising areas of improvement or creation of new structures that should be devoid of weaknesses and imperfections of analogs and they should have an economic effect through rational use of materials. Findings. Types of steel and concrete composite cable space frames and structural features of its elements are developed and considered. The steel and concrete composite cable space frame is a completely new kind of space structure system that has the original structural concept and it was designed to cover large-span industrial and public buildings. The basic elements of that structure system are modular element of the bottom chord and space steel and concrete composite module that consists of tubular rods and reinforced concrete slab. All modular elements are made in the factory. With bottom chord modular elements and space steel and concrete composite modules can be assembled three types of longitudinal elements. It is the beam element, arched element and hanging element. Also with the modules can be assembled various structure system and their combinations. Number of space steel and concrete composite modules and bottom chord modular elements, which is needed to collect steel and concrete composite cable space frames, is determined by calculation and optimal designing. Recommended dimensions of the modular elements of the steel and concrete composite cable space frames are presented. Originality. The new efficient construction roofs that appointment for covering large-span buildings were developed by the author. Practical value. Developed steel and concrete composite grid-gable roofs are designed for industrial and civil construction. Applications of developed designs for the construction of large-span covering objects provides a significant economic benefit through the efficient use of materials.

Roller rig testing at the Czech technical university

Abstract: Purpose Although the advancements in computer simulation technology have paved way to provide very reliable simulation results, track tests still play an essential role during the process of development and homologation of any railway vehicle On the other hand, track tests depend on weather conditions, are difficult to organize and are not suitable for testing vehicles in critical situations On a roller rig, the tested vehicle is longitudinally fixed and a track is replaced by rotating rollers Such device offer testing of railway vehicle running dynamics in safe and stable laboratory environment The purpose of an article is to investigate and describe roller rig testing at the Czech technical university in Prague (CTU) Methodology In the paper it is shown the history of development of the scaled CTU roller rig from the earlier stages until the current projects for which the CTU roller rig is utilized for The current design of the experimental bogie, roller rig, sensors instrumentation and types of experiments conducted at the CTU roller rig are described in more detail Findings Although the differences in vehicle behaviour on a track and a scaled model on a roller rig are not negligible, scaled roller rig experiments are found as a relatively inexpensive way for verification and demonstration of computer simulations results They are especially useful for verification of multibody system simulations (MBS) of entirely new running gear concepts Originality The CTU roller rig is currently used for the experiments with active controlled wheelset guidance According to simulations results published in many papers such systems offer, in principle, better performance compared to conventional passive vehicles However, utilization and testing of active controlled wheelset guidance on vehicles is still rare CTU roller rig serves as a tool to verify computer simulations and demonstrate benefits of active wheelset guidance Practical value Experiments conducted on the CTU roller rig confirm the possibility to significantly influence railway vehicle running dynamics by actively controlled wheelset guidance Such concept could be regarded as a possible and likely approach for the design of future railway vehicles running gears

Complex of Numerical Models for Computation of Air Ion Concentration in Premises

Abstract: Purpose. The article highlights the question about creation the complex numerical models in order to calculate the ions concentration fields in premises of various purpose and in work areas. Developed complex should take into account the main physical factors influencing the formation of the concentration field of ions, that is, aerodynamics of air jets in the room, presence of furniture, equipment, placement of ventilation holes, ventilation mode, location of ionization sources, transfer of ions under the electric field effect, other factors, determining the intensity and shape of the field of concentration of ions. In addition, complex of numerical models has to ensure conducting of the express calculation of the ions concentration in the premises, allowing quick sorting of possible variants and enabling «enlarged» evaluation of air ions concentration in the premises. Methodology . The complex numerical models to calculate air ion regime in the premises is developed. CFD numerical model is based on the use of aerodynamics, electrostatics and mass transfer equations, and takes into account the effect of air flows caused by the ventilation operation, diffusion, electric field effects, as well as the interaction of different polarities ions with each other and with the dust particles. The proposed balance model for computation of air ion regime indoors allows operative calculating the ions concentration field considering pulsed operation of the ionizer. Findings . The calculated data are received, on the basis of which one can estimate the ions concentration anywhere in the premises with artificial air ionization. An example of calculating the negative ions concentration on the basis of the CFD numerical model in the premises with reengineering transformations is given. On the basis of the developed balance model the air ions concentration in the room volume was calculated. Originality. Results of the air ion regime computation in premise, which is based on numerical 2D CFD model and balance model, are presented. Practical value. A numerical CFD model and balance model for the computation of air ion regime allow calculating the ions concentration in the premises in the conditions of artificial air ionization taking into account the main physical factors determining the formation of ions concentration fields.

The basis of mathematical description for wave model of stresses propagation in railway track

Abstract: Purpose. Modern scientific research has repeatedly cited practical examples of the dynamic effects of railway track operation that go beyond the static calculation schemes. For the track sections where the train speed is approaching to the velocity of wave propagation in the slab track layers such issues are of particular relevance. An adequate tool for the study of such issues can be the use of the wave theory of stress propagation. The purpose of the article is the creation of a mathematical description of the basic principles of the stress propagation wave model in the railway track, which can be used as a basis for the practical development of the relevant calculation system. Methodology. The model of stress-strain states of the railway track on the basis of the stress wave propagation theory is to bring together the equations of the geometry of the outline of the space systems that is involved in the interaction at a given time, and the dynamic equilibrium equations of deformation. The solution is based on the use of the laws of the theory of elasticity. The wave front is described by an ellipsoid equation. When determining the variation in time of the surface position of the ellipsoid a vector approach is used. Findings. The geometry equations of the wave motion determine the volumes of material layers of the slab track involved in the interaction at a given time. The dynamic equilibrium determination of the deformed condition of the space bounded by the wave front makes it possible to calculate both the stresses and strains, and their changes during the time of the load perception. Thus, mathematical descriptions of the processes that occur in the perception of the load by the elements of railway track at high speeds were obtained. Originality. The simulation tasks of the track and rolling stock interaction, in particular taking into account the dynamic deflection of slab track were further developed. For the first time the article presents the basics of the mathematical description of the wave stress propagation model in the railroad track, which can be used to perform practical calculations. Practical value. The obtained data can be used to justify the track construction or establishing appropriate values of permissible speeds for the introduction of train motion with high speeds.

Probabilistic-physical approach to describe and determine the reliability of cars

Abstract: Purpose. The article aims to develop an algorithm and a sequence of description and determination of car reliability to predict certain quantitative indicators of the studied elements, parts and units, or a car as a whole on the basis of probabilistic-physical approach. Methodology . For the calculation of the indicators of reliability, durability and safety of cars the probabilistic-physical method was used, which takes into account the resources consumption inevitable in the operation of cars. The methodology of quantifying the reliability is based on the study of the physical-mechanical and physical-chemical properties and parameters of various elements, with the identification of principles of the aging processes of the elements or parts (with operating time) to determine the analytical dependencies of these processes from the indicators of cars reliability. Findings. On the basis of probabilistic-physical approach it was developed a model to describe and determine the reliability of the cars. At this the method of calculation based on probabilistic-physical model is fundamentally different from all known rigorous probabilistic methods by the fact that it considers a continuous set of states of the elements, parts and systems of the car during continuous time. If there exists or (if it possible to find) the information parameter about the resource consumption of the car element with evaluation of its change speed, and knowing its limit, based on the built car reliability model with the involvement of probabilistic-physical approach, one can predict all the necessary quantitative indicators of reliability of the studied elements, parts and units or a car as a whole. Originality. The methodology of the reliability construction with the use of probabilistic-physical model with DN-distribution was further developed in the article. The specific physical interpretation of the constants of DN-distribution of failures makes it possible to evaluate them according to the results of the study of certain parameters characterizing the technical condition of the car. On the basis of probabilistic-physical approach the algorithm and the sequence of description and determination of cars reliability to predict certain quantitative reliability indicators of the studied elements, parts and units, or a car as a whole were developed. Practical value. The results make it possible to calculate in practice the quantitative indicators of reliability of cars or their individual elements for further prediction of the overall reliability during operation.

Unified verification method of electromagnetic compatibility between rolling stock and train detection systems

Abstract: Purpose. Axle counters are more and more often applied in train detection systems. The wheel sensor is a main part of each axle counter system. In parallel, more and more complex railway vehicles, especially traction ones, are a potential source of interferences influencing the operation of these train detection systems. It is the reason to verify the electromagnetic compatibility (EMC) between the signalling equipment, particularly train detection systems and new vehicles in the process of obtaining the permission for their exploitation. The measurement of interfering magnetic fields generated by vehicles is one of tests to be carried out. Methodology. For the simplification and unification purpose of the applied interference test methods the EN 50238 standard and TS 50238-3 technical specification were developed. The specification defines unified testing procedures. However, it is necessary to verify if it may replace different testing methods used in particular European states. It is the goal of the European research project financed from the TEN-T network resources. Findings and originality . This project is part of the larger project of facilitation and speeding up the ERTMS system deployment. One of nine measurement campaigns planned in the frame of this project was conducted in Poland by Railway Research Institute.

The influence of chemical composition of high-chromium cast irons on the machinability

Abstract: Purpose . This research is aimed to obtain the regression dependence of the machinability on the chemical composition of pig iron (C, Cr, Mn and Ni) in cast state. Methodology . The method of active experiment planning was used to build a mathematical model. Cast irons of composition 1.09…3.91 % С; 11.43…25.57 % Cr; 0.6…5.4 % Mn; 0.19…3.01 % Ni were studied. Cutting tools with plates 10х10 mm out of ВК8 according to State Standard 19051-80 were used for turning. Cutting modes: cutting depth – 0.8 mm, longitudinal feed – 0.15 mm/rot., spindle’s rotation frequency during turning – 200…360 rot./min. Lubricating and cooling liquids were not applied. Evaluation of iron workability was produced by determining the linear tool flank wear per unit length of the cutting path. Findings . Mathematically probabilistic equation of the regression dependence of the cutting tool’s wear on the C, Cr, Mn and Ni content in the machined cast iron were obtained. It was established that with the increase of Cr content in the cast iron to 14.8 % the cutting tool’s wear decreased as a result of formation of carbide eutectic which destroyed the doped ledeburite continuous frame. Further increase of chromium content promoted appearing of chromic carbides with high microhardness which considerably increased the tool’s wear. The conducted research shown that the minimum cutting tool’s wear 0,18 mkm/m was observed during the machining of cast iron containing: 1.09 % C, 14.8 % Cr, 2.3 % Mn and 1.2 % Ni; and the maximum wear is 48,96 mkm/m – when the content was: 3.91 % C, 11.43 % Cr, 5.4 % Mn and 0.19 % Ni. The tool’s wear reached 47.61 mkm/m during the treatment of cast iron containing 3.91 % C, 25.57 % Cr, 5.4 % Mn and 0.19 % Ni. Originality . Mathematically probabilistic model of the dependence of the cutting tool’s wear on the C, Cr, Mn and Ni content in the machined cast iron has been elaborated by the author. Practical value . The model allows optimizing the compositions of wear-resistant cast irons for castings which require the significant mechanical machining. Cast irons compositions were recommended for different exploitation conditions.

Prospects for laying the fastening of the type скд65 - б in the curvesd track sections with small radius

Abstract: Purpose To date, there is a tendency concerning complete transition of main tracks to concrete sleepers The reason for this is the lack of wooden sleepers, their high cost and low lifetime that in the curved track sections with the radius R≤300 m is only 5-7 years (this is 5 times less than the lifetime of concrete sleepers) After introduction of fastening type СКД65-Б it is possible to smoothly expand the track from 0 mm to 14 mm, and to narrow from 0 mm to 28 mm with a step 1 mm At the increased train load on the track of 75…130 kN in a horizontal plane, which is characteristic for the curved track sections R≤300 m the violations in terms of track geometry often take place It results in the frequent surfacings, periodicity of which at the fastening type СКД65-Б is absent for today Therefore the purpose of the article is the development of recommendations concerning maintenance of the track in a plan with the fastening type СКД65-Б Methodology The methodology of research is based on the comparative estimation of influence of the track width change dynamics on the periodicity of surfacing in the plan in the case of the use of fastening type ДО and СКД65-Б Findings With the help of the developed research methodology it was established that the first implementation of adjusting the track width at fastening type ДО is necessary to be executed on the 14 th month and at the fastening type СКД65-Б on the 28 th month of operation Originality It was first described and expressed using the empiric dependence the process of the track width change, and periodicity of its adjusting in the case of the fastening type СКД65-Б use Practical value The developed recommendations will allow in time to execute adjusting of the track width at fastening type СКД65-Б and ensuring the safety of train motion at the same time

Estimation of subgrade strengthening influence using soilcement elements

Abstract: Purpose . The aim of this work is to identify dependencies and options to strengthen the roadbed and a weak base by grouting piles. Analysis of software package SCAD to assess the effect of the selected option of strengthening the construction of spatial subgrade models. Methodology . In this paper the method of calculation of the soil mass in the software package SCAD is considered, which is a universal accounting system of finite-element analysis of structures and is focused on solving problems of designing buildings and structures rather complex structure. The finite element method is among the most modern and effective methods for the calculation of structures for various purposes. In the simulation, we get a complete picture of the stress-strain state of the study area, as well as the value of the limit load, rainfall, and so on. The spatial model based on the finite element volume, to better address the real characteristics of the soil mass, meets all the geometric characteristics of size and natural subgrade and the top structure the path that has been adopted in Ukraine. Findings . It was found that the most effective option to strengthen the roadbed, when applying grouting piles at the base of the subgrade and body, is to strengthen the five piles. At the same time there is even strengthen the soil mass at the level of 25 … 30% of the entire depth. However, even with the strengthening of the only two piles at the base of the effect of the strengthening of 14.1%. Established equation is linear and describes the decrease in strain. Taking into account the results of the research can be concluded that the consolidation is proportional to the depth with any number of piles. The dependence of the strain on the number of piles adheres to a polynomial function. Strengthening the bases of the subgrade and body depth also occurs in proportion with any number of piles. Originality. Design scheme generation algorithm for the calculation of the subgrade on a weak basis by finite element method was determined. The selection of strength characteristics of soils and the design parameters for use during the numerical simulation was completed. Load process simulation of the system by rolling stock was grounded. Practical value. Analysis of stress-strain state of «weak base-subgrade» allows you to see the basic laws work the soil and take the necessary measures to enhance the cross-section profile of jet-grouting elements.

To the issue of extending the service life of cars for transportation of pellets

Abstract: Purpose . Freight rolling stock of «Ukrzaliznytsia» primarily has cars that are overaged. The same situation is observed in the park of specialized cars. So the car fleet for the transport of pellets consists of about 50% of cars that served one-and-a-half and more lifetimes. However, the volume of shipments of iron ore is constant for a number of years. In this regard, there is a need to find methods to justify continuing useful life of cars and to assess the conformity of residual life of the car body structure to operating load for an extended period of use. Methodology . When selecting the cars for the test their condition underwent technical diagnosis in order to identify the level of corrosion and mechanical damage. The next stages of the tests included the experimental determination of the loading level and the stress state of car body carcass based on strength and endurance tests and the evaluation of the possible values of the extended period of operation. Findings . Pre-test diagnosing of cars showed that the technical condition of cars for transportation of pellets, as a whole, is in satisfactory condition. Carried out static and impact strength tests with subsequent evaluation of strength of the car structural elements showed that the strength of the latter is provided in accordance with regulations and such cars do not threaten the traffic safety. Shock endurance tests have shown that all the cars have passed endurance tests with no damage that would impede testing and could not be removed during scheduled repairs. The cars had lifelength that allows prolong their useful life after one-and-a-half lifetime. Originality . The work presents the estimate of the residual life of bodies of pellet transportation cars, which spent one-and-a-half of the set lifetime. Practical value . The experimental results confirm the possibility of extending the service life of cars after one-and-a-half life of their lifetime. The results of the work can be used to extend the service life of cars for transportation of pellets. Part of the rolling stock, which had to be written off in connection with the expiration of the set one-and-a-half lifetime without additional measures can continue its lifetime.

Obtaining of new knowledge in concerning «air conditioning» at the railway transport: scientometric aspect

Abstract: Purpose . The research aimes at obtaining of new knowledge in «air conditioning» direction development at railway transport using products and services of Web of Science (WoS) scientometric database. Chronological frameworks of the studied scientific articles are – 2010-2015 years. Methodology . In order to obtain relevant empirical data the authors reviewed the world literature on the paper topic with the use of full-texts and abstract databases. The algorithm of «incremental» actions in WoS was considered according to: 1) forming the «core» of publications; 2) establishment of the most «top» issues; 3) identifying the most intellectually productive authors; 4) determining the representation level of thematic publications of Ukrainian scientists in WoS; 5) the presence of collaboration among scientists from different countries on the investigational subject. Findings . The authors proved: 1) climate comfort, energy efficiency and thermal comfort are the top-themes of «air conditioning» direction at railway transport; 2) Ukrainian scientists have not yet joined to the global processes in the thematic scientific information sharing; 3) the most intellectually productive authors of scientific articles are China’s scientists; 4) there is no information about international collaboration of scientists on the investigational subject. Originality . The authors firstly conducted scientometric research in the field of railway transport (subject area «air conditioning») on the basis of products and services in the global WoS citation database. Practical value . Based on the results, one can correct personal exploration research of individual scientists or research teams as well as predict further prospects of the subject «air conditioning» direction at the railway transport. Survey data may also be useful in the study of the «Scientific information system and scientometrics» subject, organization of workshops, training courses, etc.

Relationship Between Rolling and Slip Resistance in Rolling Bearings

Abstract: Purpose. About one of the causes of slip rolling is known from the second half of the 19th century, it was believed that the slip resistance appears at the place of contact due to different speeds on the arc of contact. Only in the mid-20th century it was proved that this resistance is negligible in rolling resistance. However (for some unknown reason) it is ignored the fact that in practice in rolling bearings may rotate both the inner ring with a stationary outer one, and vice versa almost in equal relations. It is not taken into account the fact that the ball or roller in the rolling bearings runs the different distance along the roller path of the outer and inner bearing cages in one revolution. This fact is not taken into account in determining the calculated values for the friction coefficient of a rolling bearing reduced to the shaft. Therefore, the aim of this work is to determine the influence of path length on the track riding the outer and inner race of the bearing on the determination of the calculated value of the coefficient of friction of rolling bearings is given to the shaft. Methodology. The solution technique is based on the theory of plane motion of a rigid body, the theory of Hertzian contact deformation and the analytical dependencies for determination of coefficient of rolling friction. Findings. The obtained dependences on determination of rolling resistance of the balls or rollers along the bearing tracks of inner and outer bearing cages as well as path difference metering of the rolling on them allows to analytically obtain the rolling resistance and slipping for any size of bearings and different devices of bearing units. It is also possible at the design stage of rolling nodes to handle not only the design but also the content of the node. Originality . Using the analytical dependences for determination of the rolling resistance of bodies at point and line contacts, and also account for the difference in the path of the rolling ball or roller on the outer and inner cages of the bearing one can more accurately find the rolling resistance in the bearings. Practical value . The obtained dependences allow designing the bearing units with minimal energy consumption.

Energy saving during operation of equipment with non-controlled electric drive in locomotive depot

Abstract: Purpose. To conduct research of electric motors in order to obtain the results that will assess the degree of energy saving due to electric loss reduction in the equipment with non-controlled electric drive. Methodology. The paper proposes an engineering method for determination of active power losses in the motors of the equipment with non-controlled electric drive in locomotive depot during load changes on the motor shaft. It is necessary to analyse the reduction of active power losses in the motor and the power supply network when an under-loaded motor is replaced with a motor having less power. Findings. After the calculations performed by the authors, it was found that for electric motors, in case of reducing the load factor from to active loss reduction after the motor replacement for the less powerful one ranges from 0.58 kW to 2.865 kW. Also, the calculations were carried out on the example of electric motors with a lower synchronous speed, the effect of under-loaded motor replacement increases in terms of active power loss reduction. The greatest effect is achieved when the load factor is . Originality. For the first time the paper outlines the issues of energy saving efficiency for the equipment with non-controlled electric drive in locomotive depot by replacing the under-loaded motors with the less powerful ones. As long as there is a significant amount of the considered electric drives, it may cause severe losses, taking into account the peculiarities of their operation. Practical value. The obtained research results allow us to solve the problem of replacement of under-loaded motors in locomotive depot equipment with the motors having less power as efficiently as possible in terms of reducing electric losses. For instance 90-kW motor of a washing machine can be replaced with 75-kW motor when the load factor is , this can significantly reduce the performance losses. This method can be applied not only in locomotive depot but also for all equipment with non-controlled electric drives that operates in under-load mode.

Concrete based on modified disperse cement system

Abstract: Мета В науковій статті потрібно розглянути визначення типів зв’язків, що утворюються в модифікованій цементній матриці бетону, та оцінку якості цих зв’язків у неоднорідному матеріалі для визначення геометричних та фізичних співвідношень між структурою модифікаторів і цементної матриці Методика Для досягнення поставленої мети проведені дослідження мікроструктури дисперсно модифікованої цементної матриці бетону та механізму структуроутворення модифікованої цементної системи бетону природного тверднення Визначені методи надійної оцінки міцності бетону Результати Автором запропонована модель просторової структури цементної матриці бетону, модифікованої шляхом дисперсного армування кристалогідратами Вихідним об’єктом дослідження є сукупність елементарних об’ємів (чарунок) цементної матриці та система просторового розподілу в цих об’ємах армуючих кристалогідратів Встановлено, що найбільш небезпечні дефекти у вигляді тріщин в об’ємі бетону при твердненні формуються в результаті виникнення внутрішніх напружень, головним чином, у зоні контакту цементна матриця – заповнювач, або в області, що межує з найбільш крупними порами бетону Наукова новизна Встановлений механізм розвитку процесу формування початкової міцності та жорсткості модифікованої цементної матриці за рахунок швидкого росту кристалогідратів у просторі між частинками дисперсного армуючого модифікатора Оскільки вільному росту кристалів перешкоджає брак простору, кристали взаємно проростають, утворюючи щільну структуру, яка обумовлює зростання міцності Практична значимість Дисперсне модифікування цементної матриці дозволяє одержати довговічні бетони спеціального призначення з проектними експлуатаційними властивостями Розроблена технологія дисперсного модифікування в’яжучої речовини, встановлені особливості механізму структуроутворення модифікованої цементної системи, а також використання принципу конгруентності комплексу технологічних впливів фізико-хімічним процесам гідратації клінкерних мінералів дозволили розробити технологічні основи бетонів спеціального призначення

Numerical prediction models for air pollution by motor vehicle emissions

Abstract: Цель . Научная работа предполагает: 1) разработку 3 D численных моделей, которые позволяют рассчитывать процесс загрязнения атмосферного воздуха выбросами автотранспорта; 2) создание моделей, которые давали бы возможность прогнозировать уровень загрязнения атмосферного воздуха в условиях городской застройки. Методика. Для решения задачи по оценке уровня загрязнения атмосферного воздуха выбросами автотранспорта используются фундаментальные уравнения аэродинамики и массопереноса. Для решения дифференциальных уравнений аэродинамики и массопереноса используются конечно-разностные методы. Для численного интегрирования уравнения потенциала скорости применяется метод условной аппроксимации. Уравнение для потенциала скорости, записанное в разностном виде, расщепляется на два уравнения, причем на каждом шаге расщепления неизвестное значение потенциала скорости определяется по явной схеме бегущего счета, при этом сама разностная схема – неявная. Для численного интегрирования уравнения рассеивания выбросов в атмосфере применяется неявная попеременно-треугольная разностная схема расщепления. Выбросы от автотрассы моделируются серией точечных источников заданной интенсивности. Разработанные численные модели составляют основу созданного пакета прикладных программ. Результаты. Разработаны 3 D численные модели, которые относятся к классу « diagnostic models ». Данные модели учитывают основные физические факторы, влияющие на процесс рассеивания вредных веществ в атмосфере при выбросах от автотранспорта в городе. На основе построенных численных моделей проведен вычислительный эксперимент по оценке уровня загрязнения воздушной среды на улице. Научная новизна. Авторами разработаны численные модели, которые позволяют рассчитать 3 D аэродинамику ветрового потока в условиях городской застройки и процесс массопереноса выбросов от автотрассы. Выполнены расчеты по определению зоны загрязнения, которая формируется возле зданий, расположенных вдоль автомагистрали. Практическая значимость. В работе рассмотрены эффективные численные модели, которые могут быть применены при разработке мероприятий по охране окружающей среды при эксплуатации автомобильного транспорта в городе. Разработанные модели позволяют оценить размеры, форму и интенсивность зоны загрязнения возле автомагистрали.

Use of microcontroller for measuring shaft speed of diesel locomotive hydraulic transmission

Abstract: Purpose. The article considers the process of development and improvement of tachometer data collectors for the data-measuring diesel locomotive hydraulic transmission test system, which will give the possibility of obtaining the source data to conduct further studies of the technical condition of diesel locomotive hydraulic transmission. It is supposed to provide a solution to the problem of development and improvement of tachometer data measuring tools of the previously created data-measuring diesel locomotive hydraulic transmission test system, starting out from the possibility of modification of the existing locomotive hydraulic transmission test-bench at the Dnepropetrovsk Diesel Locomotive Repair Plant «Promteplovoz». Methodology . The researchers proposed in the work a method of modifying the existing tachometer sensor of the automated microprocessor system for the locomotive hydraulic transmission test-bench in the conditions of a diesel locomotive repair plant. It is applicable by substantiating the choice of the required tachometer sensor measuring method, as well as by using the necessary hardware and software to accomplish the goal with the ability to integrate into the data-measuring system for diesel locomotive hydraulic transmission testing. Findings. The available equipment of the locomotive hydraulic transmission test-bench allowed for design of the optical type speed sensor based on the existing sensor D-2MMU-2. The factory testing with the use of a sensor prototype resulted in determination of the required and sufficient sampling time for sensor operating microcontroller. Originality. The available equipment of the locomotive hydraulic transmission test-bench allowed for design of the optical type speed sensor based on the existing sensor D-2MMU-2. We developed the operation algorithms for the microcontroller that processes the signals from this sensor. The sensor was factory-tested. According to the data sample obtained during the tests, we showed the possibility of reducing the sensor information retrieval frequency. Practical value. The designed sensor significantly reduces the cost of development of the diesel locomotive hydraulic transmission test-bench, besides it can be used when developing similar hydraulic transmission test-benches of other wheeled vehicles and the like. The designed sensor has a greater accuracy than that of D-2-2MMU and considerably lower production cost in comparison with current tachometer sensors. The measurement results are input data to perform further studies in order to determine the technical condition of UGP750-1200 hydraulic transmission during the factory post-repair testing.

Research of dependence of belt conveyer drive power on its design parameters

Abstract: Purpose. A drive is one of the basic elements of belt conveyers. To determine the drive power it is necessary to conduct calculations by standard methodologies expounded in modern technical literature. Such calculations demand a fair amount of time. The basic design parameters of a belt conveyer include type of load, design efficiency, geometrical dimensions and path configuration, operation conditions. The article aims to build the parametric dependence of belt conveyer drive power on its design parameters, that takes into account standard dimensions and parameters of belts, idlers and pulleys. Methodology. The work examines a belt conveyer with two areas: sloping and horizontal. Using the methodology for pulling calculation by means of belt conveyer encirclement, there are built parametric dependences of pull forces in the characteristic conveyer path points on the type of load, design efficiency, geometrical dimensions and path configuration, operation conditions. Findings. For the belt conveyers of the considered type there are built parametric dependences of drive power on type of load, design efficiency, geometrical dimensions and path configuration, operation conditions, taking into account the belt standard dimensions and corresponding assumptions in relation to idler and pulley types. Originality. This is the first developed parametric dependence of two-area (sloping and horizontal) belt conveyer drive power on type of load, design efficiency, geometrical dimensions and path configuration, operation conditions that takes into account standard dimensions and parameters of belts, idlers and pulleys. Practical value. Use of the built drive power dependences on design parameters for the belt conveyers with sloping and horizontal areas gives an opportunity of relatively rapid determination of drive power approximate value at the design stage. Also it allows quality selection of its basic elements at specific design characteristics and requirements. The offered dependences can be used for determination of general character of drive power dependence on the project efficiency.

Metal structures survivability assessment when simulating service conditions

Abstract: Purpose. The research is aimed at improving the quality and reliability of measures of primary and secondary protection of metal structures at manufacturing companies, to prolong the service life of cyclically loaded structures of production facilities taking into account the corrosion level of danger. Methodology. Authors proposed to use the principles of process approach for statement and realization of management problems of operational service life in corrosion environments. The principles of ensuring reliability on the level of corrosion danger include justification of stages sequence for survivability assessment of a structural metalwork based on the strategy of DMAIC (define, measure, analyze, improve, control): definitions, measurements, analysis, improvement and monitoring of measures of primary and secondary corrosion protection. Findings. Providing control measures from corrosion according to the criterion of corrosion danger allows providing requirements of reliability of structural metalwork based on calculated provisions of the limiting conditions method and solving the problems of management in technological safety during the expected service life of structural objects. Originality. The developed strategy of maintenance of the industrial facilities on an actual state includes the process approach to resource management by creation of system for the account and the functional controlling, risk analysis and regulation of technological safety in production facilities of the enterprises. Realization of the principles of process approach to management of technological safety at the object level is directed to perfecting of tools and methods of anticorrosive protection, extension of a resource taking into account indexes of survivability (,) and justification of program measures to ensure the reliability of enterprises(PER). Practical value. On the basis of process approach to quality and reliability management, generalizations of the natural and numerical researches directed to justification of design solutions of primary and secondary protection of a metalwork at the given level of corrosion danger of a metalwork the organizational measures of PER including assessment of integral characteristics of constructional suitability, technological rationality and risk analysis of signs corrosion danger of objects are developed.

Study of working capacity of the marshalling yard

Abstract: Purpose . The scientific paper has a purpose to choose rational technological parameters of the transportation organization process, which would enable the freight train movement with the most efficient train traffic arrangement, the decrease in idle time due to the increased speed of cargo delivery and the increase in the working capacity of the marshalling yard. Methodology . The work presents the technical and operational characteristics of marshalling yards in Europe and Ukraine. The research methods include the station operation analysis, the car traffic flow analysis, analysis of the train sheet, the DU-1 natural sheets upon arrival and departure of trains. Schemes were developed for calculating working capacity of necks, rehandling capacity of marshalling hump, acceptable levels of system loading. Findings . The research resulted in the calculated working (rehandling) capacity of the main elements of the station. Daily loads of marshalling hump and turnout tracks vary significantly by variations and gradations of movement volume. This affects the idle time of trains and, in general, the value of the criterion according to which the optimal technical equipment, optimum interaction of the subsystems and gridiron of the station will be chosen. This criterion must take into account the costs of technical equipment, construction of tracks, locomotives, as well as related operating costs in all cases. Thus, the selection of the optimal interaction should establish the economically viable level of operational reliability of the sub-systems, their technical and track capacity. Originality . By increasing the productivity of train departure channel, marshalling hump and turnout tracks it is possible the thetrain handling processes and reduce the car idle time. Intensification of production processes in marshalling yards provides a reduction in car turnover and in idle time and high economic efficiency of capital investments. The work covers the issues related to improving the efficiency of functioning of marshalling yards in the railway transport reforming conditions. Practical value . Using the methods of determining the rational working (rehandling) capacity of marshalling yards for distribution of train traffic flows between them makes it possible to improve the quality indicators of marshalling yard operation.

Research of the stress state of a modified in-situ concrete

Abstract: Purpose . The article focuses on investigation of the stress state of a modified in-situ concrete of natural hardening. Methodology . To achieve the aim, the research of the microstructure of the modified cement matrix of concrete, as well as the mechanism of structure formation of modified concrete with natural hardening was conducted; the methods for reliable evaluation of concrete strength were defined. Findings . The development of internal stresses affects the properties of concrete differently. With an increase in temperature-shrinkage deformations in time and, thus, with increasing structural stresses in the cement sheath around the grains of the filler two opposite processes may develop: zone of plastic flow or cracking. Originality. It was established that the structural features complex of the modified concrete when the load transfer leads to the formation of extensive zones of prefracture which is able to absorb a significant amount of elastic strain energy that provides the design deformation properties of the concrete for special purposes. Ideas about the definition of the criteria of cracking modified concrete, hardening under natural conditions had further development. Practical value . The resulting equations allow to solve the problem about the minimum level of structural stress in monolithic concrete in a saturated large placeholder, as well as to assess the influence of structural stresses on the properties of concrete. In normal concrete with a relatively thin cement sheath at temperature-shrinkage deformations, high tangential and low radial tension occur. In vivo, this stress is higher as a result of higher values of Δe(τ), which is not observed in the modified concrete. In the modified concretes only tangential stresses are the greatest danger to structures. The change of shrinkage stress with time is straightforward. The total temperature-shrinkage deformations have a sawtooth graph. For modified concrete the amplitude is 48…53% less. This will allow solving a number of technological challenges in the construction of monolithic buildings.

Rigidity of intermediate fastening screws and spikes for wooden sleepers under the action of horizontal lateral forces

Abstract: Мета. Незважаючи на постійне збільшення протяжності ділянок із безстиковою колією на залізобетонних шпалах, дерев’яні шпали – це один із варіантів підрейкових опор, що експлуатуються на достатньо великій кількості напрямків, зокрема, залишаються безальтернативними в кривих радіусами до 350 м, а також у головних коліях метрополітенів. Основними видами прикріплювачів у найбільш розповсюджених типах проміжних рейкових скріпленнях для дерев’яних шпал є колійні костилі та шурупи. Оскільки існуючі в кривих ділянках колії особливості контактування системи «колесо-рейка» мають суттєвий вплив на процеси взаємодії залізничної колії та рухомого складу, в роботі необхідно визначити жорсткість колійних шурупів та костилів, які безпосередньо приймають участь у формуванні просторової жорсткості вузлів проміжних рейкових скріплень при дії горизонтальних поперечних сил. Методика. Дослідження жорсткостей прикріплювачів проводились експериментально для двох типів проміжних рейкових скріплень – ДО та «Метро». Для проведення експериментальних випробувань було обрано 10 дослідних ділянок на коліях регіональної філії «Південна залізниця» ПАТ «Укрзалізниця», та 8 – на головних коліях КП «Харківський метрополітен». Кожна з дослідних ділянок знаходилась у приблизно однакових експлуатаційних умовах, але мала різну величину пропущеного тоннажу. Результати. Отримані значення жорсткості колійних костилів та шурупів. Наукова новизна . Авторами вперше були отримані експериментальні дані щодо зміни жорсткостей прикріплювачів (колійних шурупів та костилів), залежно від терміну експлуатації для магістральних залізниць та колій метрополітенів. Це дає змогу виконувати розрахунки величини горизонтальних поперечних сил у кривих ділянках колії (зокрема в кривих із радіусами менше 350 м), а також прогнозно оцінювати зміну їх рівня в процесі експлуатації. Практична значимість . На основі отриманих експериментальних даних було встановлено, що зміна жорсткості колійних шурупів та костилів, залежно від терміну служби, носить нелінійний характер. Проведені дослідження дозволяють більш раціонально підходити до питання визначення оптимальної конструкції проміжних рейкових скріплень, виходячи з конкретних умов експлуатації, а також сприятимуть розробці заходів щодо підвищення надійності роботи вузлів проміжних рейкових скріплень для дерев’яних шпал.