Science and Transport Progress

16-24

Authors: B. E. Bodnar, M. I. Kapitsa, O. B. Ochkasov, R. O. Korenyuk

Purpose. In difficult economic conditions, cost reduction of electricity consumption for the needs of production is an urgent task for the country’s industrial enterprises. Technical specifications of enterprises, which repair diesel locomotive hydraulic transmission, recommend conducting a certain amount of evaluation and regulatory tests to monitor their condition after repair. Experience shows that a significant portion of hydraulic transmission defects is revealed by bench tests. The advantages of bench tests include the ability to detect defects after repair, ease of maintenance of the hydraulic transmission and relatively low labour intensity for eliminating defects. The quality of these tests results in the transmission resource and its efficiency. Improvement of the technology of plant post-repairs hydraulic tests in order to reduce electricity consumption while testing. Methodology. The possible options for hydraulic transmission test bench improvement were analysed. There was proposed an energy efficiency method for diesel locomotive hydraulic transmission testing in locomotive repair plant environment. This is achieved by installing additional drive motor which receives power from the load generator. Findings. Based on the conducted analysis the necessity of improving the plant stand testing of hydraulic transmission was proved. The variants of the stand modernization were examined. The test stand modernization analysis was conducted. Originality. The possibility of using electric power load generator to power the stand electric drive motor or the additional drive motor was theoretically substantiated. Practical value. A variant of hydraulic transmission test stand based on the mutual load method was proposed. Using this method increases the hydraulic transmission load range and power consumption by stand remains unchanged. The additional drive motor will increase the speed of the input shaft that in its turn wil allow testing in closer to real conditions as a result of increased load on the hydraulic transmission. Increased load on the hydraulic transmission will help to detect possible defects and hence will improve the quality of transmission repairs.

35-44

Authors: Yu. L. Bolshakov, A. V. Antonov

Purpose. The paper is devoted to the detailed analysis of interrelations at the contact point of friction pair «contact wire – current collector insert». In the work it is necessary: 1) to examine quality of manufacturing of specimens of current collector elements from different manufacturers; 2) to narrow the range of hardness for carbon inserts; 3) to develop a technique of sorting carbon current collector inserts for the structural parameters. Methodology. The executed work was based on the use of the theory of reliability of technical systems and electromechanical processes. Findings. The paper studies the interrelation at the contact point of friction pair «contact wire – current col lector insert», the connection was established between the hardness and electrical resistivity. It is proposed to narrow the range of carbon inserts hardness. The method of sorting coal collector inserts in hardness was developed, and the research has revealed the discrepancy of current collector inserts with existing regulations. It was proposed to equip the pantographs slide with current collector elements using special scheme and to develop a specialized research facility, which will be possible to conduct studies of the interaction of the friction pair «contact wire – current collector insert». Originality. In the course of the study the current collector inserts the sharp structural heterogeneity and fluctuations of the density of the material along the length of the insert were established. The dependence between hardness of inserts and electrical resistivity was established. It was analyzed and concluded about the need to reduce the values of the normal range of hardness. Based on the results of the research, the experimental dependences were obtained and proposed the method for sorting carbon current collector inserts for the structural parameters. Practical value. The obtained results of coal current collector inserts define the need to use method for sorting the coal current collector inserts and the use of a special scheme for equipping pantograph slide. It will allow optimizing their work, knowing the limitations for edges in exploitation and the type of the objective function that should be achieved. The proposed measures can reduce the intensity of the electrical and mechanical wear of materials friction pair «contact wire – current collector inserts». The use of specialized research facility for the study of the friction pair, will allow carrying out the studies to determine the intensity of wear of contact surfaces of the pair of friction and the coefficient of friction at various external factors.

57-64

Authors: V. P. Velinets

Purpose. Calculation of a railway track on the strength is one of the sections of the overall complex research problems of interaction track and rolling stock. This paper describes the experimental study of horizontal transverse stiffness of railway rails with various strands of rail fasteners. Materials of this article should be relevant and will make it possible to calculate the strength of railway track using the correct and corrected performance of horizontal transverse stiffness of rail threads. Methodology. Determination of horizontal transverse rigidity of rail yarns with different designs of rail fasteners was conducted by measuring the quantities of transverse displacement of rails calculation points – namely the head and sole. For research the specialist equipment was created, made up of lineside jack DC-20, equipped with a hydraulic pressure gauge to measure pressure and rigid rod for horizontal rail stop in the thread, the opposite of the jack. Lateral movement of the head and sole of the track were recorded, and measured with indicators of clock type within a few hundredths of a millimeter. The horizontal lateral load on the rail jack was created by the injection pressure in the cylinder which was fixed with manometer into the jack. Load of rails was conducted over 2 tons of degrees ranging from 0 to 8 tons. To obtain reliable measurement results of lateral movement of the head and the base rails, its movement was conducted for each type fasteners not less than in 3 sections. Measurements were carried out without the creation of vertical load. Findings. With the developed method was found transverse displacement magnitude of rails calculation points at different designs of rail fasteners. Originality. The experimental studies were first found the mentioned horizontal transverse stiffness of rail threads in the head and sole of modern designs for different rail fasteners. Practical value. The values of horizontal transverse stiffness of rail threads in the head and sole of modern designs for different rail fasteners that were found by the author make it possible to calculate the strength of railway track using correct and corrected values of these characteristics.

78-87

Authors: R. M. Yosyfovych

Purpose. The paper is devoted to the study and evaluation of residual life for defective rails P50 operated on the roads of the Kyiv subway, which are taken out of service because of defects 11.1-2 on the side of the rolling surface of the rail head. Methodology. The studies were performed with the use of experimental methods: testing of samples of defective rails in the cyclical strength of the pulse machine and testing of defective rails in the static load limit on the hydraulic vertical press. Findings. The performed experiments indicate that on the tests basis in 2 million cycles is only a small development (increase in size) 0.5-0.7 mm of existing code defects 11.2 as a result of shedding the particles of crumble out metal on the side of the rails head of working prototypes. The intensity and the catastrophic development of defects, such as 11.2, or transformation of these defects in defects such as 21.2 or 30G.2 did not happen in any case. Originality. For the first time in Ukraine with the theoretical calculations substantiated the greater possibility of defects formation of contact fatigue origin in the form of spall and jag of metal on the surface of the rail, at the edge of the head. It is the result of the creation of a high degree of stress nonequilibrium compression in this area, due to the high values of principal normal stresses and appearance of large shear stresses in the body of the head at a depth of 2.5-3.5 mm, exceeding the yield strength and metal endurance. The tests of experimental prototypes of defective rails on high cycle endurance (based № = 2,1h10 cycles) with periodic defectoscopic control were conducted. Practical value. In experiments, the new data of the resistance ability to spall rail defects on the surface of the head of rolling on the code 11.1-2 long-term cyclic loading equal to operational magnitude at the wheel load test of 2 million cycles was obtained. That is, the defective rails can have residual life of not less than 30 million. t. gross.

101-109

Authors: V. S. Loveikin, Yu. O. Romasevich

Purpose. It is necessary to select modes of motion to reduce the dynamic loads in the mechanisms. This choice should be made on optimization basis. The purpose of research is to study methods of synthesis regimes of mechanisms and machines motion that provide optimal modes of movement for terminal and integral criteria. Methodology. For research the one-mass dynamic model of the mechanism has been used. As optimization criteria the terminal and comprehensive integral criteria were used. The stated optimization problem has been solved using dynamic programming and variational calculation. The direct variation method, which allowed finding only approximate solution of the original problem of optimal control, has been used as well. Findings. The ways of ensuring the absolute minimum of terminal criterion have been set for each method of problem solving. The stated characteristics show softness changes of kinematic functions during braking of mechanism. They point to the absolute minimum of adopted terminal criterion in the calculation. Originality. It is necessary to introduce new variables in the system equations during the solving of optimal control problems using dynamic programming to achieve an absolute minimum of terminal criteria. In general, to achieve a minimum of n-order terminal criterion an optimization problem should find relatively (n+1)-th order function. When optimization problems is solving by variational calculation in order to ensure a minimization of n-th order terminal criterion by selecting the appropriate boundary conditions, it is necessary to solve the Euler-Poisson 2(n+1)-th order equation (subject to symmetric setting boundary conditions). It is a necessary condition for an extremum of the functional with the (n+1)-th order integrant. Practical value. Minimizing of adopted terminal criterion in the calculation allows eliminate the brunt in kinematic gearing of mechanisms, which increases their operational life. In addition, the reducing of the acceleration increasing intensity of system driving mass (for example, rotor of electric motor) allows reducing undesirable energy losses in a drive.

118-126

Authors: S. V. Myamlin, O. H. Reidemeister, A. L. Pulariia, V. O. Kalashnyk

Purpose. The vast majority of passenger car fleet of «Ukrzaliznytsia» have cars with outlasted service life. In this regard there is a need to find methods to justify the extending useful life of passenger cars and to assess the car body frame residual life conformity to the operating load for the next life time. Methodology. The selection of cars enforced technical diagnostics of cars to detect the level of corrosion and mechanical damage. The following steps provided the car body frame strength analysis on the basis of experimental static and impact strength tests, the longitudinal force effect endurance tests as well as assessment and forecasting of conformity of car body operating life for the next period. Findings The car survey before testing showed that the technical condition of sleeper cars (SSC) is better than that of open-type cars (SOC). So, in SSC cars the thinning of the main load-bearing elements due to corrosion does not exceed 10%, there are no cracks, deformations, rack breakages, etc. At the same time in SOC cars the thinning due to local corrosion reached 35%. There are deformations and corrosion damage of side sill Zshape of both cars, single corner post breakages, damage to the joints of longitudinal tie rod and span bolsters. The conducted static and impact strength tests with following strength assessment of the car structural members showed that the strength of the latter is provided according to the normative documents, and these cars pose no threat to traffic safety. The impact endurance tests showed that all the cars passed the endurance tests without damage, which would prevent from testing and could not be removed during the next depot repair or overhaul, and had life length that allows them to extend the useful life for the next period. Originality. The results of experimental studies show that passenger cars after 28 … 30 and 33… 35 years of operation meet the requirements of strength and safety in accordance with regulatory documents and allow, provided the impact endurance, reasonable extending of the car service life. Practical value. The part of the car fleet, which was to be written off based on the service life, may extend lifespan without additional measures.

134-148

Authors: A. O. Shvets, К. I. Zhelieznov, А. S. Аkulov, О. M. Zabolotnyi, Ye. V. Chabaniuk

Purpose. The analytical study of the connection between the longitudinal force, acting on the light-weight car, lateral and vertical forces of interaction in the contact zone «wheel – rail» with the lift resistance factor value is to provide a simple relationships between them. Methodology. Research was conducted by the method of mathematical modeling of loading the freight car when driving at different speeds on straight and curved sections of a track. Findings. Even in the absence of «lift» accordingly the classical train stability theory, as the hinge-rod system, the presence of the longitudinal compressive forces may become a factor provoking cars derailment. The main reason of wheel climbing on rails is the combination of processes of dynamic interaction between the hunting vehicle and the track with simultaneous action of longitudinal compressive forces, and not the destabilization of train as a hingedrod system. To assess the impact of the longitudinal forces value on the lift resistance factor there are presented the calculation results for the empty gondola car motion, model No. 12-532, on 250 m radius curve with 150 mm rise and cross starting of car underframe relating to the track axis in 50 mm guiding section. The calculations were made in such a curve excluding the inertial forces from outstanding acceleration and taking into account the unbalanced acceleration with the permissible speed of 65 km/h. Originality. This study provides the technique of determining the lift resistance factor by longitudinal forces, which is somewhat different from the standard one, as well as evaluates impact of rolling stock speed on this factor. Practical value. The authors clarify the current method of determining the lift resistance factor by longitudinal forces and assess the impact of rolling stock speed on the value of this factor. From these studies one can conclude that because of cars hunting their lift is possible even when the train as hinge-rod system does not lose stability. The developed proposals allow reducing the number of car derailment by taking into account important parameters and characteristics during the process of calculation and design that increase their stability in the rail track especially in case of increased speed of freight trains.

164-143

Authors: V. V. Pristinskaya

Purpose. On the Railways of Ukraine a very large number of slab tracks are operated with cracks. Many scientific works of previous years are dedicated to improving the design of slab tracks. The main causes of defects are: poor exploitation of the track; insufficient physic-mechanical characteristics of concrete; poor quality of initial materials. It is therefore necessary to develop an optimum concrete mix for the manufacture of these concrete products. Methodology. To assess the impact of individual factors and effects of their interactions on properties of concrete mix and concrete method of experimental and statistical modeling was used. At this, methodological fundamentals of mathematical experiment planning in concrete technology and modern methods of optimization of composite materials were taking into account. Based on the obtained data during the planned experiment conducting, including15 studies and using the computer program MathCad, were obtained the regression equations, which describe the relevant physical and mechanical properties of concrete. On the basis of the equations with the help of computer program MATLAB R2012b the graphs were drawn, illustrating the dependences of system response from the changes of two factors at a fixed value of the third factor. Findings. Firstly was the analysis of cracks that occur in the process of operation in the constructions of slab tracks. Further reasons of possible occurrence of these cracks were presented. In the process of the conducted research the author has concluded that for rational concrete mix development it is necessary to conduct the planned experiment with the use of quality materials. It was established that to increase the strength, chemical additives should be added in to concrete mix, it will let reduce cement amount. Originality. Experiments proved the usage of modern chemical additives in order to improve the properties of concrete. Models were developed, reflecting characteristics of concrete strength. With their help one can optimize concrete composition. Practical value. Research proved that the usage of more sustainable concrete mix for production of slab tracks will increase their strength, and with it the reliability of these designs mechanical properties.

183-197

Authors: T. О. Kolesnykova, I. A. Kliushnyk

Purpose. Publication of scientific periodicals in the Universities is very important and necessary element in the infrastructure of scientific communication. The aim of the article is: 1) providing a new model of publication system of the University scientific periodicals (on the example of Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan – DNURT); 2) studying the peculiarities of the «Library publishing» model (Library Publishing) and library as a new participant in the publication of world scientific periodicals of the University; 3) description of the developed software automation typesetting of scientific articles and their integration into international databases of scientific and technical information. Methodology. The scientists investigated: 1) the system of publication of scientific periodicals at DNURT; 2) integration system of electronic versions of periodicals and individual articles of scientists from DNURT into the world scientific databases; 3) publishing activity of the scientific and technical library of the University. Findings. The authors proved the need for the fast updates in each higher education institution of Ukrainian management system of scientific periodicals and the creation of the periodicals development concept. The conditions for the occurrence of positive changes in the publishing process in Universities were determined and named as a new participant in these processes – University library. The list of new tasks inherent in the scientific periodicals of the Universities was presented. The software product «Digital designer» was created as a new applied information technology solution to extend the functionality of the basic system information of the publication according to its editorial policy. Originality. The scientists studied the transformation process of the organizational structure of scientific periodicals publishing in the Universities of Ukraine and the world. It is proved that in today's conditions for the University publishers of scientific periodicals transition to a new model of publication system of the University scientific periodicals is the most rational, a feature of which is the rejection of purely printing and the introduction of hybrid model of publication. This model assumes that traditional print products is complemented with a form of «Epub ahead of print» (e-publication before printing) using the journal's website as an operational channel for the dissemination of publications. Practical value. The Universities transition to the new model system for the publication of scientific periodicals, modern concept formation of the scientific journal, creation of relevant software tools (e.g. automation of typesetting the scientific articles and the integration of publications in the database of scientific and technical information) will allow improving the quality of journals and their competitiveness at the international level.