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    5 (71) випуск. Наука та прогрес транспорту
    (Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпро, 2017)
    UK: У статтях наведені наукові дослідження, виконані авторами в Дніпропетровському національному університеті залізничного транспорту імені академіка В. Лазаряна та інших організаціях. Статті присвячені вирішенню актуальних питань залізничного транспорту по наступних напрямках: автоматизовані системи управління на транспорті, екологія на транспорті, експлуатація та ремонт засобів транспорту, матеріалознавство, залізнична колія, інформаційно-комунікаційні технології та математичне моделювання, нетрадиційні види транспорту, машини та механізми, транспортне будівництво, рухомий склад і тяга поїздів. Вісник становить інтерес для працівників науково-дослідних організацій, викладачів вищих навчальних закладів, докторантів, аспірантів, магістрантів та інженерно-технічних працівників
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    Features of Design of Tied-Arch Bridges with Flexible Inclined Suspension Hangers
    (Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Samosvat, V. O.; Rongling, Zhang; Hololobova, Oksana O.; Buriak, Serhii Yu.
    EN: Purpose. Investigation and analysis of the hanger arrangement and the structural stability of a Network arch bridge – a tied-arch bridge with inclined hangers that cross each other at least twice. It is also necessary to make a comparative analysis with other types of hanger arrangements. Methodology. The authors in their research investigateda large number of parameters to determine their influence in the force distribution in the arch. Eventually they determined optimal values for all parameters. These optimal values allowed developing a design guide that leads to optimal arch design. When solving this problem, the authors used three-dimensional finite element models and the objective was to determine the most suitable solution for a road bridge, with a span of 100 meters, consisting of two inclined steel arches, located on a road with two traffic lanes, subjected to medium traffic. The virtual prototype of the model is performed by finite element simulator Midas Civil. Findings. In this study, for the bridge deck, a concrete tie appears to be the best solution considering the structural behavior of network arches, but economic advantages caused by easier erection may lead to steel or a composite bridge deck as better alternatives. Design requirements and local conditions of each particular bridge project will decide the most economic deck design. Originality. To ensure passenger comfort and the stability and continuity of the track, deformations of bridges are constricted. A network arch is a stiff structure with small deflections and therefore suitable to comply with such demands even for high speed railway traffic. A network arch bridge with a concrete tie usually saves more than half the steel required for tied arches with vertical hangers and concrete ties. Practical value. Following the study design advice given in this article leads to savings of about 60 % of structural steel compared with conventional tied arch bridges with vertical hangers.
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    Dynamic Behavior of Two-Span Continuous Concrete Bridges under Moving of High-Speed Trains
    (Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Marinichenko, Oleksii H.
    EN: Purpose. The scientific work provides a comparison of the results of the movement of a high-speed passenger train across the bridge, obtained as a result of finite element modeling in the SAP2000 software package, and real tests of a double-span concrete railway bridge. Analysis of the rigid characteristics of flying structures. Methodology.The numerical method presented in this study shows valid results concerning the dynamic analysis of the behavior of bridges in conditions of high-speed train traffic. The factors influencing the dynamic behavior of bridges under moving loads, the influence of design parameters and rolling stock, as well as the interaction of the train and spans are determined. The system was used in the form of moving concentrated forces simulating the axes of the train. Findings. Maximum movements and accelerations were obtained as a result of the dynamic calculation for different speeds of the train and compared with practical tests. The correctness of the model of a span structure with regard to continuous ferroconcrete spans was verified. Originality. Within the framework of the work, the latest test results were used, including those with speeds calculated on the prospect of rail passenger traffic. For these tests, a model of a span structure was developed. Practical value. The results of the research can be used to plan the introduction of high-speed train traffic on existing and planned flying structures of reinforced concrete bridges. An approach to the design of span structures that will be effective when passing high-speed passenger trains is implemented.
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    Interaction of Soil-Cement Pile Supporting Structures with the Body of a Landslide
    (Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Ihnatenko, Dmytro Yu.; Petrenko, Volodymyr D.; Tiutkin, Oleksii L.
    ENG: Purpose. Analysis and comparison of the landslide slope finite element model calculation results of the appliance of soil-cement piles, depending on the variation of the retaining structure rigidity, makes it possible to evaluate the effectiveness of their application and the cooperative work of piles with the displacement body. It also makes it possible to make a conclusion about the advantages of using this anti-landslide protection method of the slope. Methodology.Analysis of geomorphological data obtained from the results of laboratory studies of soils on the slope section is considered. Creation of a three-dimensional finite-element slope model according to the constructed sections and depths of the soil layers. Calculation of the nonlinear problem of finite element modeling of the slope with applying of soil-cement piles of various rigidity. Findings. The obtained results of calculating the finite element model of the landslide slope, and the analysis of the stress-strain state of the construction with soil-cement piles has been carried out.Originality. Despite the widespread of using soil-cement piles as enclosing structures for the construction of foundation pits and reinforcement of foundations of emergency structures, special attention should be paid to the study of the expediency of using soil-cement retaining pile structures on landslide areas. Practical value. It is known that soil-cement retaining piles are expediently in use as a protective element, which interacts quite well with the ground environment due to its structure of the initial material. Using of modern computer programs of finite element modeling makes it possible to calculate the efficiency of the use of soil-cement piles and to determine the parameters of the necessary retaining structure according to the given geological structure of the slope, and also, depending on its shape and the physical characteristics of the soils, to compare the performance of different protective landslide structures types.
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    Method of Constructing the Dynamic Model of Movement of the Multi-Mass System
    (Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Reidemeister, Oleksii H.; Kalashnyk, Volodymyr O.; Shykunov, Oleksandr A.
    EN: Purpose. The scientific work is intended to develop a methodology for describing the structure of the railway vehicles (they are considered as a system of rigid bodies connected by rigid, elastic and dissipative elements), which would allow us to obtain the equations of motion in an easily algorithmized way. Methodology. When constructing the model, authors tend to ensure that its structure reflects the structure of the mechanical system, that is, parts of the model must correspond to parts of the car. In this case, the model takes the form of a hierarchically organized graph whose vertices correspond to the bodies, attachment points of the connecting elements and to the connecting elements themselves, and the edges describe the sets of processes that are related to the incident vertexes. As a rule, these are movements and forces: for the edge between the body and the attachment point they are generalized movements of the body and the general forces acting on it; for the edge between the attachment point and the connecting element - the movements of the point and the forces arising in the element. To each vertex there corresponds a group of equations describing the motion of the system. The nature of the equations depends on the type of the vertex. For the body it is the equations of body motion; for the point - the expressions for the point displacements through generalized displacements of the body and generalized forces acting on the body, through the forces arising in the connecting element; for the connecting element - the expression for the forces arising in it through the deformation of the element. The graph can be regarded as oriented. The direction of the edge is chosen in such a way that for each vertex the values on the right-hand side of the vertex-associated equation would correspond to the incoming edge, and in the left-hand side - to the outgoing edge. Findings. A technique for constructing a dynamic model of oscillations of railway vehicles as a system of rigid bodies is developed on the basis of their description using hierarchically organized graphs. The technique was tested to construct a model of spatial oscillations of a 4-axle freight car with an axial load of 25 tons in Simulink package. Originality. For the first time, a technique has been developed for describing the structure of a railway vehicle using a hierarchical graph, which makes it possible to obtain equations of motion in an easily algorithmized manner. Practical value. The proposed methodological approach will allow, after creating a library of bodies and connecting elements, to significantly reduce the time spent on modeling the oscillations of different vehicles.
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    Influence of Structural Parameters of Low-Carbon Steel on Electric Arc Burning
    (Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Vakulenko, Ihor O.; Plitchenko, Serhii; Murashova, Nataliia H.
    EN: Purpose. The article is aimed to evaluate the influence of structural parameters of low-carbon steel on arcing process.Methodology. The values of the micro- and substructure characteristics of the electrode wire metal were changed by varying the parameters of heat treatment and cold deformation by drawing. The degree of plastic deformation was obtained by drawing blanks from different initial diameter to final dimension of 1 mm. The thermal treatment was carried out in electric chamber furnace of the SNOL-1,6.2,5.1/11-IZ type. The temperature was measured by chromel-alumel thermocouple and the electromotive force was determined using the DC potentiometer. In order to obtain the substructure of different dispersion degree the steel (after quenching from temperatures and tempering at 650°C for 1 hour) was subjected to cold drawing to reduction 17 – 80%. To form structure with different ferrite grain size the steel after drawing was annealed at 680°C for 1 hour. The microstructure was examined under a light and electron transmission microscope UEMV-100K at the accelerating voltage 100 kV. The grain and subgrain sizes were evaluated using the methodologies of quantitative metallography. A welding converter of the PSG-500 type was used to study the arc welding process of direct and reverse polarities. Findings. The experimentally detected value of the welding current, which depends on the degree of deformation during wire drawing, under conditions of stable arc burning of direct polarity is about an order of magnitude lower than the calculated value. Similar difference was found for the arc of reverse polarity: the experimental value of the welding current is 5...6 times less than the calculated value. Dependence analysis shows that, regardless of the polarity of the welding arc, a good enough agreement between the calculated and experimental values of the welding current is limited to deformations of 60%. For deformation degrees of more than 60%, the differences are explained by qualitative changes in the dislocation cell structure. Originality. In the conditions of stable arcing of different polarity for the electrode of low-carbon steel, an extreme dependence of welding current on the degree of cold plastic deformation was observed. Practical value. Influence of ferrite grain size of electrode wire on the value of welding current is much greater than that from substructure presence.
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    Підвищення ефективності роботи електроприводу постійного струму на основі використання суперконденсаторних накопичувачів електроенергії
    (Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Муха, Андрій Миколайович; Костін, Микола Олександрович; Куриленко, Олена Яківна; Ципля, Гліб Володимирович
    UKR: Мета. У науковій роботі необхідно проаналізувати розширення діапазону навантаження та здійснення рекуперативного гальмування (РГ) електричного приводу постійного струму шляхом застосування суперконденсаторних накопичувачів електроенергії. Методика. Для розв’язання поставленої задачі використовуються методи теорії електроприводу, імпульсної електротехніки та методика розрахунку перехідних електромагнітних процесів у лінійних електричних колах при наявності в них суперконденсаторів. Результати.Здійснено суттєве збільшення жорсткості механічної та електромеханічної характеристик двигунів послідовного збудження, що дає можливість використання електроприводу постійного струму при навантаженні, значно меншому, ніж 15–20 % від номінального. Виконано чисельні розрахунки процесу дії суперконденсаторного накопичувача електроенергії при різкому зменшенні навантаження тягового електродвигуна електровоза постійного струму. Обґрунтовано можливість РГ електроприводу постійного струму з двигуном послідовного збудження. Виконано розв’язання рівнянь процесу зарядження й розрядження суперконденсаторного накопичувача в режимі РГ. Досліджено вплив величини ємності на характер підтримання в часі струму збудження електродвигуна в режимі малих навантажень. Наукова новизна. Розроблено теоретичні підходи щодо перетворення м’яких (механічних та електромеханічних) характеристик у жорсткі електродвигунів постійного струму послідовного збудження. Вперше запропоновано й обґрунтовано новий, комбінований, метод РГ двигунів послідовного збудження. Подальший розвиток отримали методи оцінки параметрів блока ємнісного накопичувача з урахуванням критеріїв надійної паралельної роботи суперконденсаторів із обмоткою збудження електродвигуна. Практична значимість. Запропоноване та обґрунтоване авторами перетворення м’яких характеристик у жорсткі дозволяє використовувати загальнопромислові електроприводи з двигунами послідовного збудження й при малих навантаженнях, а в тягових електроприводах – знизити інтенсивність буксування колісних пар електрорухомого складу. Розроблена методика розв’язання перехідних рівнянь дає можливість врахувати випадковий характер зміни напруги на двигуні в режимах зарядження та розрядження суперконденсаторного накопичувача. Запропонований комбінований метод РГ робить можливим здійснення РГ й при малих швидкостях обертання якоря електродвигуна, тим самим підвищуючи енергоефективність експлуатації електроприводів цього типу.
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    Water Reality in Ukraine and Worldwide
    (Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Dolina, Leonid F.; Mashykhina, Polina B.; Karpo, Alina A.; Mishchenko, Andrey A.
    EN: Purpose. The paper analyzes the state of water management in Ukraine and worldwide, as well as the best practices in this area. Methodology. The study was carried out based on the analysis of literature sources and reporting data on the state of water management in Ukraine, European countries, the USA (2010-2016). Findings. The water state analysis in the regions of Ukraine showed that the quality in most cases is close to or meets the requirements for drinking water. Drinking tap water requires post-treatment in all regions of the country. The main issue for today is the production of the necessary equipment for treatment plants. Unfortunately, not all equipment is produced in Ukraine. The condition of rural water pipelines is of particular concern. Among the tested pipelines 7.3% do not comply with the rules and regulations. At the same time, only 25% of villages in Ukraine are provided with centralized water supply. Originality.The authors presented the results of a comprehensive review of the world's issues on disinfection of drinking and waste water, where various methods are used, partly in combination with each other in Ukraine and the worldwide. The main unresolved issue today is the issue of the residual quantity of drugs in the drinking water. The main environmental threat of the world scale is the presence of medicines in drinking water. The treatment facilities are not suitable for the decomposition or trapping of medicinal products. Nowhere in the world there is protection from these substances. One of the key issues in the solution of drinking water production is seawater desalination. To reduce the cost of desalination of sea water the SWRO-membrane technology is used. Practical value. Water problems are number one problems all over the world and in Ukraine as well. It is necessary to provide for additional financing to solve problems in the preparation and purification of waters, not with whatever funds remain, taking into account the fact that water is the basis of life on earth as a whole, the health and life of the nation depends on the quality of the water supply source.