Кафедра "Вища математика" ДІІТ (з 2022 року кафедра увійшла до складу факультету Будівництво, архітектура та інфраструктура)

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ENG: Department "Higher Mathematics" DIIT (since 2022, the department moved to the warehouse of the faculty Budіvnitstvo, architecture and infrastructure)

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3D численная модель для оценки территориального риска при теракте
(Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпро, 2018) Беляев, Николай Николаевич; Калашников, Иван Владимирович; Клименко, Ирина Владимировна; Козачина, Виталий Анатольевич
RU: Цель. Работа предполагает разработку 3D численной модели для оценки территориального риска в случае теракта с использованием химического агента. Методика. Для описания процесса рассеивания в атмосфере химического агента, выброшенного в случае теракта, используется трехмерное уравнение массопереноса примеси в атмосферном воздухе. Уравнение учитывает поле скорости ветрового потока, атмосферную диффузию, интенсивность эмиссии химического агента, наличие зданий возле места выброса химически опасного вещества. Для численного интегрирования моделирующего уравнения используется конечноразностный метод. Особенностью разработанной численной модели является возможность оценки территориального риска в случае теракта при различных метеоусловиях и наличии зданий. Для расчета поля скорости ветрового потока в условиях застройки применяется трехмерное уравнение для потенциала скорости. Результаты. Разработанная численная модель и пакет программ могут быть использованы для оценки территориального риска как в случае терактов с применением химических агентов, так и в случае экстремальных ситуаций на химически опасных объектах и транспорте. Построенная численная модель может быть реализована на компьютерах малой и средней мощности, что позволяет широко использовать ее для решения задач рассматриваемого класса, при разработке плана ликвидации аварийной ситуации. Представлены результаты вычислительного эксперимента, позволяющие оценить возможности предложенного метода оценки территориального риска в случае теракта с использованием химического агента. Научная новизна. Предложена эффективная численная модель для оценки территориального риска в случае теракта с применением химически опасного вещества. Метод может быть использован для оценки территориального риска в условиях городской застройки, что позволяет получать адекватные данные о возможных зонах поражения. Метод основан на численном интегрировании фундаментального уравнения массопереноса, выражающего закон сохранения массы в жидкой среде. Практическая значимость. Предложенный метод оценки территориального риска в случае теракта с применением химического агента может быть использован для расчета зон поражения возле административных зданий, центров и других социально значимых объектов.
Building Models to Optimize Vehicle Downtime in Multimodal Transportation
(PC TECHNOLOGY CENTER, 2023) Razghonov, Serhii; Lesnikova, Iryna; Kuznetsov, Vitalii M.; Kuzmenko, Albina; Khalipova, Nataliіa; Chernikov, Danylo; Zvonarova, Olha V.; Prokhorchenko, Halyna; Horulia, Mykola; Bekh, Petro V.
ENG: Sustainable development has become the main focus of transport policy and planning around the world. One of the practical goals when performing multimodal transportation is the optimization of logistics costs. That is, the object of research is the process of multimodal transportation. Empirical research shows that the problem of optimization of transportation costs can be solved by different methods. But the result will be similar. In the given approach, only one component of the transportation process is subject to optimization, which is the overload time. The solutions are based on the method of mass service theory and the method based on fuzzy logic. With the help of these methods, based on practical data, time parameters were calculated that characterize overloading from railway transport to road transport. The application of the method of a weakly formalized process in relation to transport logistics was considered, taking into account not only quantitative estimates but also qualitative, vaguely defined criteria that do not lend themselves to formalization, and the relationships between them. The model was developed for further research of this process, prediction of its behavior, optimization of functioning. It is based on the technology of fuzzy sets. The results obtained using the agent model based on the mass service network and the model based on fuzzy logic differ within the permissible specified limits of no more than 5–7 %. The application of fuzzy logic in the logistics of multimodal transportation is relevant and gives the best results compared to traditional methods of the theory of mass service systems. The article includes comparisons that reflect the advantages of the proposed approach. The obtained results are of a practical nature and can be used to make a decision on choosing a route and/or when transferring from one mode of transport to another.
Choosing the System of Locomotive Maintenance in View of the Effect of Dependent Failures
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2018) Bodnar, Borys Ye.; Ochkasov, Oleksandr B.; Hryshechkina, Tatiana S.; Bodnar, Yevhen B.
ENG: Purpose. Improving the efficiency of the use of locomotives by choosing a rational maintenance system that takes into account the assessment of the effect of dependent failures on the cost of their life cycle is the main purpose of this paper. Methodology. The relevance of introducing LCC (life cycle cost) approaches in locomotive facilities is explained by the introduction of new locomotives with on-board control and diagnostic systems, as well as the development of the theory of traction rolling stock maintenance systems. The cost of a locomotive as a traction unit ceases to be the determining factor. This is because the locomotive maintenance and repair cost for the entire period of its operation is much higher than the initial cost of the locomotive. The paper analyses the existing approaches to managing the cost of the life cycle of locomotives at the stages of selecting, updating, upgrading and operating the traction rolling stock. The necessity of improving the methods for assessing the degree of influence of reliability indicators of locomotive assemblies on the choice of the maintenance system and the cost of the locomotive life cycle is substantiated. Findings. It is proposed to use the concept of «the effect of dependent failures» when calculating the cost of locomotive renewal after unscheduled repairs and its life cycle cost. We improved the methods for determining the cost of unscheduled repairs, taking into account dependent failures and the coefficient of assessment of the effect of dependent node failure on the locomotive maintenance system. The proposed coefficient will determine the nodes, the failure of which affects the renewal cost more than their nominal value. It will also help to take into account the probable losses due to node failure during the development and adjustment of the locomotive maintenance system. Originality. For the first time, it is proposed to use the concept of the effect of de-pendent failures to calculate the locomotive renewal cost when performing unscheduled repairs, as well as the loco-motive life cycle cost. Practical value. The improved calculation method for determining the cost of unplanned repairs with account taken of dependent failures can be used to compare and evaluate different variants of the locomotive maintenance system and to develop the locomotive diagnostic systems.
Comparative Analysis of the Parameters of the Strength of the Subgrade at the Transition to the Higher Axial Loading up to 25 t
(IOP Publishing, Kharkiv, 2019) Radkevych, Anatolii V.; Petrenko, Volodymyr D.; Tiutkin, Oleksii L.; Andrieiev, Volodymyr S.; Mukhina, Nataliya
ENG: Abstract. A review of the scientific and technical literature on the re-alignment of the route during the transition to high axial load from the accepted today (23.5 t / axis) to the perspective (25 t / axis) shows that in the stage of preliminary researches imitation modeling of the earth web by the finite element method (ITU) as the most convenient, accurate and illustrative of the known numerical methods. In order to provide recommendations on the strength of the subgrade when moving to a higher axial load up to 25 t / axis, an analysis was conducted, the essence of which was to compare the stress-strain state of the subgrade at two loads per axis: 23.5 t / axis (existing ) and 25 (perspective). All the geometric and deformation characteristics of the formation are taken from data on a two-track section with a height of embankment of 3. The deformation characteristics are chosen so that the working material of the formation is in accordance with the average indices of deformation capacity of the railways used. The ITU train load calculus makes it possible to obtain all the factors of VAT in it, which is the main purpose of the study of the strength of the earth cloth, and allows to forecast their development in the future.
Consideration of Dependent Failures Impact on Selecting the System of Locomotive Maintenance
(Kaunas Univ. of Technology, Palanga, Lithuania, 2019) Bodnar, Borys Ye.; Ochkasov, Oleksandr B.; Bodnar, Yevhen B.; Hryshechkina, Tatiana S.; Skvireckas, R.
ENG: Modern measures aimed at reducing the operating costs are closely related to such concepts as LCC and RAMS-approach. The article analyzes the existing standards that regulate their usage. The purpose of the research is to improve the methodology for determining the renewal costs of locomotive nodes with due regard to dependent failures. To describe the propagation of dependent failures in the system, the authors propose to use the wave approach. The dependent failures impact on the system is determined on the basis of information about the relationship between elements and data from a technological-economic map concerning the cost of locomotive nodes renewal. To take into account the probabilistic nature, the authors propose to use the methods of expert research for determining the probability of failure of dependent elements. The authors proposed a method for determining the probability of the locomotive nodes breakdown considering the dependent failures. The method of calculating the average cost of unscheduled repair, considering the dependent failures of interrelated elements was improved. For the first time, a recurrence relation on a set is deduced, by which the volume of damage is calculated at the dependent failures of elements in a complex system. The coefficient, which will allow assessing the impact of dependent failures on the maintenance system and the life cycle cost of a locomotive, is proposed. On the basis of the proposed method, the calculations for the electric equipment of electric locomotives, DE1 series were made. A comparison of the renewal cost of electrical equipment with considering the dependent failures of related elements was made.
Designing of Developed Surfaces of Complex Parts
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Tyshchenko, Serhii S.; Krasniuk, Andrey V.; Ulchenko, Tatiana V.; Shcherbak, Andriy S.
EN: Purpose. The paper focuses on ensuring the rational choice of parameters of the mating surfaces of parts when designing process equipment based on the methods of artificial intelligence. Methodology. The paper considers the geometric model of a ruled developed surface, the conditions of existence of such a surface and provides a generalized algorithm for surface plotting regardless of the type of the working element or the machine-building product. One of the most common technical surfaces are the ruled ones, among which a special position is occupied by developed surfaces (thanks to their differential-parametric properties): surface tangent plane is n contact along the rectilinear generator and does not change its position in space when changing the point of contact; surfaces can be produced by bending sheet metal. These provisions enable a product manufacturer to save significant material and energy means, therefore, the development of geometric models of such surfaces is an important task. Findings. We analyzed the geometrical model of the developed surface which is incident to two guides. Experimental studies have shown the application prospectivity of semi-digger moldboards on moldboard plows, particularly on the double-deck ones. Taking into account the operating speed of the plow 2.8 m/s, the plant residues plowing percentage for plow with semi-digger moldboards is 98.9%, and with the digger ones – 96.1%. Originality. According to results: 1) the approaches to solving the problem of recognition of wear conditions of the tested interface, depicted by its conceptual model, were elaborated; 2) the corresponding algorithms of the computational procedures were built; 3) the mathematical model that determines the effect of the parameters of the contacting surfaces on their performance properties – linear wear rate during the normal wear and tear was developed; 4) for this model the theoretical prerequisite of use for the random mating study were designated. Practical value. Currently, these areas produced significant results which are in line with modern requirements of construction engineering. The process of parametric model optimization generates a plurality of desired values of the surface parameters. There are formed the algorithms for automatic recognition of design features and operation of interfaces by their images, which are set by a structured set of formal signs. The recognition result is the interface designation to a particular group, each of which corresponds to an individual computational model of quality parameters normalization.
Determination of Integrated Indicator for Analysis of the Traffic Safety Condition for Traction Rolling Stock
(Kaunas University of Technology, Kaunas, Lithuania, 2018) Bodnar, Borys Ye.; Bolzhelarskyi, Yaroslav V.; Ochkasov, Oleksandr B.; Hryshechkina, Tatyana S.
ENG: Traffic safety is a major priority in railway transport operation. Locomotive facility is one of the responsible units in general system of railways. A complex and cumbersome system of indicators is used in locomotive facilities to analyze the operation. The existing system makes it difficult to analyze the general level of work organization in the locomotive facilities. Purpose of the study is to determine the methodology of forming a certain dimensionless indicator (or group of indicators) that will reflect the general level of safety in the locomotive facilities. As the research methodology it was chosen principal component analysis as the corresponding mathematical apparatus, which makes it possible to analyze the existing indicators characterizing the performed work and the traffic safety condition with the necessary degree of informativity. As a result, the main components and the degree of their influence on the general level of traffic safety in the locomotive facilities are set. The indicators that have the most influence on the technical and safety components of the integrated indicator of traffic safety condition are determined. Originality of the work is that it for the first time proposes the concept of index of traffic safety condition and the method of its determination using the principal component analysis. Practical value of the work lies in the fact that the ranking of technical and safety components according to the degree of their influence on the general traffic safety index has been performed. Also, the locomotive units which have the greatest influence on the traffic safety condition and reliability were determined.
Formation of Contact Interaction Zones during Infiltration of Composite Materials Depending on Binder Composition
(Chuiko Institute of Surface Chemistry of NAS of Ukraine, Kyiv, 2025) Shtapenko, Eduard Ph.; Syrovatko, Yuliya V.; Levkovich, O. O.
ENG: In the production of macro-heterogeneous composite materials with a metal matrix by the oven infiltration method, it is necessary to control the contact interaction processes occurring at the filler and binder interfaces. The width of the resulting contact interaction zones at the interfaces is an indicator of intensity of these processes. The intensity of contact interaction processes depends on many factors, including the binder alloy composition. The paper examines the effect of binder alloying components on the change in the surface tension of the binder alloy, and, so on the intensity of contact interaction processes occurring at the interfaces during infiltration of composite materials. Calculations of changes in the surface tension of iron-based binder upon alloying with C, P, B and Mo are presented using the formalism of the electrochemical interaction of regular solutions. The iron melt was considered as a solvent, while C, B, P and Mo were considered as dissolved components. It was taken into account that formation of an interface resulted in the appearance of unbalanced charges and energetic influence on the ions distributed in the melt. Adsorption of dissolved components on the filler surface decreased the surface tension of the binder. When estimating the thickness of the layer of excess ion concentration at the surface, we assumed that the binder surface tension depended on the number of adsorbed ions. Our calculations were expressed in accordance with the concept of mole equivalent. It is found that alloying of the Fe–C–B–P binder with Mo causes a decrease in the difference between the surface tension values of the alloyed binder and pure iron melt by 28.5 %, and, accordingly, 22.6 % reduction of thickness of the layer of excess ion concentration. The results obtained were compared with the results of experimental works with regard to composite materials with W–C fillers and iron binders alloyed with C, B, P, and Mo. It is determined that when the Fe–C–B–P binder is alloyed with Mo the width of contact interaction zones in the composite materials decreases by 15–20 %. Therefore, the results of calculations using the proposed method for changing the thickness of the layer of excess ions at the interfaces when alloying the binder correlate with the experimental data for changes in the width of contact interaction zones of composite materials.
Mathematical Simulation of Spatial Oscillations of the "Underframe-Track" System Interaction
(Kaunas University of Technology, Kaunas, Lithuania, 2018) Klimenko, Irina V.; Černiauskaitė, L.; Neduzha, Larysa O.; Ochkasov, Oleksandr B.
ENG: The article presents mathematical simulation of spatial oscillations of the "underframe-track" system interaction. It describes a design scheme of the freight-passenger electric locomotive, taking into account details of construction and the mathematical model of its spatial oscillations. The connections imposed on the system, the forces arising in them, as well as the mutual displacements of all the bodies in the system are considered. Differential equations of system oscillations are composed on the basis of Lagrange's equations of the second kind taking into account details of construction of the electric locomotive. The paper presents some results of calculations for the cases of an electric locomotive movement on the straight sections of the track, curves of small and mean radius.
On the Question of Choosing the Optimal Strength Criterion of Soils and Rocks
(Kaunas University of Technology, Kaunas, 2021) Shashenko, Oleksandr; Shapoval, Volodymyr S.; Skobenko, O.; Zhylinska, S.; Andrieiev, Volodymyr S.; Markul, Ruslan V.; Mukhina, Nataliya
ENG: Based on the analysis of solutions to the classical problems of soil mechanics and geomechanics on determining the critical height and angle of the slope, as well as active and passive pressure on the enclosing structures, to identify the optimal strength criteria and the limits of their application, which allow predicting the destruction of ideally free-flowing, ideally plastic rocks, as well as rocks characterized by internal friction and specific cohesion, which is necessary for calculating the strength and stability of underground and open mine workings in the supercritical region - after the destruction of the near-contour region. The areas of application of some criteria for the strength of soils and rocks are outlined and substantiated. It is shown that, in contrast to the known strength criteria of Z.T. Benyavsky, Hoek - Brown and A.N. Shashenko Coulomb - Mohr strength criterion and our proposed modification of the strength criterion of A.N. Shashenko allow predicting the destruction of ideally - free flowing, ideally - plastic rocks, as well as rocks characterized by internal friction and specific cohesion.
Optimal Structural Reservation of Technical Systems
(Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпро, 2018) Semenets, Sergey N.; Nasonova, Svetlana S.; Semenets, Gаlina I.
EN: Purpose. The purpose of the article is to give designers of highly reliable technical systems that do not have special knowledge in the field of optimization and programming skills, a simple and accessible mathematical tool for choosing the optimal solution for structural redundancy of systems. Methodology. The article poses the problem of optimal structural redundancy of technical systems. Two typical redundancy schemes are considered: a) a separate «hot» backup scheme; b) a separate «cold» backup scheme. The computational models for estimating the reliability of redundant systems are formulated. We offer optimization models that allow us to find a rational option for reserving a system that is being designed, taking into account conflicting requirements for its reliability and cost. These models are numerically implemented in the operating environment of the Excel spreadsheet as applied to the main object, consisting of 7 elements. The optimal variants of reserving this object according to the «hot» and «cold» separate reservation schemes are given. Findings. Calculated models for estimating reliability, as well as models for optimizing the systems reserved for the «hot» and «cold» separate backup schemes, have been developed. With the use of the Excel spreadsheet, the optimal options for reserving 7 element objects are found for separate «hot» and «cold» backups. Originality. New computational models for estimating the reliability of redundant systems are proposed, as well as optimization models developed on the basis of these, which are formulated using the decomposition of unknown initial problem of structural redundancy into binary components. In this case, the obtained optimization models belong to the class of problems of non-linear mathematical programming with binary variables, for the numerical solution of which (even for a sufficiently large dimension) well-known packages of applied computer programs, in particular, the MS Excel spreadsheet, are well adapted. Thus, the process of solving the initially very complicated problem of optimal structural redundancy is much simpler and reduced to performing elementary actions in the corresponding software interfaces. Practical value. The proposed calculation models for estimating the reliability of redundant systems, models for optimal structural redundancy, and the methodology for their formation, in order to simplify further numerical implementation, can be useful in solving problems of ensuring the reliability of technical systems in the early stages of their design.
Optimization of Non-Stationary Electric Field Parameters in Order to Increase the Efficiency of Chamber Furnaces
(Національний технічний університет «ХПІ», Харків, 2020) Yerofieieva, Alina A.; Artemchuk, Viktor V.; Mukhina, Nataliya; Karasov, Oleksandr P.
EN: The presented work is devoted to the urgent task of increasing the energy efficiency of chamber furnaces.The purpose is to solve the problem connected with optimizing the parameters of the non-stationary mode of the applied electric field in order to increase the effi-ciency of the chamber furnaces. Methodology. According to well-known methods of experiment planning, we obtained a set of Pareto-incomparable solutions of the chamber furnace, taking into account the voltage between the burner and the metal charge, which is the basis of the algorithm. Findings. The work proposes an innovative system acting the process of metal heating in a chamber furnace. The result is a developed chamber furnace control system, in which the optimal values of control actions at each step of the heating cycle are determined according to the created algorithm. The proposed control system is universal, because after miscalculations it produces the dynamics, accord-ing to which one needs to change the value of direct-current voltage and gas supply with a step in time to perform any given mode of metal heat treatment. The experimental studies conducted on a real chamber furnace with a bogie hearth at Zaporozhye Titanium and Magnesium Combine confirmed this. The analysis of the obtained metal annealing temperature curve showed that the implementation of the optimal values of the control actions, obtained using the developed algorithm, provides a high uniformity and better quality heating of the metal. The dynamics of gas consumption by the chamber furnace during the heating cycle in the basic mode, without voltage supply, and under the condition of its use in accordance with the performed optimization testify to the possibility of significant energy efficiency improvement of the considered furnaces. Conclusions. For the first time we proved the possibility and efficiency of using a non-stationary electric field in the furnace chamber as a control action, which confirms the originality of the obtained results. The practical value of the research is that the developed control algorithm is universal in terms of metal heat treatment and can be used in chamber furnaces of any industrial enterprise, while one heating cycle reduces the consumption of natural gas by more than 10 %.
Parameter Optimization of the Locomotive Running Gear
(Kaunas University of Technology, Kaunas, Lithuania, 2018) Klimenko, Irina V.; Kalivoda, Jan; Neduzha, Larysa O.
EN: In principle all railway vehicles exhibit lateral oscillations, also called a hunting motion. Stability of hunting motion usually decreases with increasing running velocity and the speed at which hunting motion becomes unstable limits the maximal permissible speed of railway vehicle. When designing a new rolling stock, it is necessary to tune the parameters of a vehicle suspension so that the critical velocity is higher than the maximum operational vehicle speed. In the paper the Nelder-Mead optimization is proposed as the method useful for finding the optimal vehicle parameters at which the maximum critical velocity is reached. This optimization method was applied to the locomotive DS3. The results are presented and discussed in the paper.
Quantum-Mechanical Modeling of the Interaction between Carbon Nanostructures and Metal Ions
(Pleiades Publishing, Ltd, 2021) Tytarenko, Valentyna V.; Shtapenko, Eduard Ph. ; Voronkov, Eugene O.; Zabludovsky, Volodymyr O.; Kolodziejczyk, Wojciech; Kapusta, Karina; Kuznetsov, Vitaliy N.
EN: In order to investigate a deposition mechanism, authors have proposed a set of quantum chemical models for formation of fullerene C60 and single-wall carbon nanotubes (SWNTs) C48 metal complexes with Co, Ni, Cu, and Zn. Obtained results proving that adsorption of Co, Ni, Cu, Zn ions on a surface of fullerene C60 and SWNT C48 from the aqueous solution of electrolytes is possible with formation of stable metal-doped carbon nanoparticle complexes. Minimum energy complexes of C60-Co and C60-Cu have corresponded to the structure where ion is located above the center of C6 cell. Meanwhile, C60-Ni complex reach a minimum energy when ion is above the middle of a C-C bond, and for C60-Zn complex the most stable conformation is the one when ion is upon the carbon atom. All the optimized structure for metal complexes with C48 has shown ions been located above the C6 cell’s center.
Rational Recovery Model of Depot Processing Equipment at the Industrial Enterprise
(Дніпропетровський національний університет залізничного транспорту імені акдеміка В. Лазаряна, Дніпропетровськ, 2014) Kapitsa, Mykhaylo I.; Grishechkina, Tatiana S.
ENG: Purpose. The problem of the maximum resources recovery of rolling stock repair depot of industrial enterprise with limited resources consumption, which are used in the system is today’s topical question.The main factors that affect the repair depot operation of industrial enterprise are reviewed. The most significant factors, affecting the quality of the repair depot, are emphasized for further study, specifically - the state of the major repair equipment of a sector. There is a need to minimize the impact of the unsatisfactory state of this factor. Methodology. The formed task of major equipment rational repairing in the mathematical sense is based on the solution of a vector optimization problem. In this case the target functions are the monetary funds spending and time expenditure for repairing. Findings. The mathematical model of optimal equipment maintainability of the repair department at the industrial enterprise was developed by the authors. On the example the choice model of optimal path for equipment repairing of enterprise repair department is described. Originality. As a result of the conducted research the repairing system of major equipment of industrial enterprise sectors was improved. As the mathematical model of rational system recovery of industrial enterprise repair depot we recommend apparatus of class problems of vector optimization. Practical value. Using the proposed model of major equipment repair system of the repair depot at the industrial enterprise will improve the quality of the department by increasing the efficiency of primary resources - time and monetary funds - which are spent by the sector in order to repair its techniques.
Safety Performance Analysis of the Movement and Operation of Locomotives
(Kaunas University of Technology; Publishing House “Technologija“, Kaunas, Lithuania, 2018) Bodnar, Borys Ye.; Ochkasov, Oleksandr B.; Bodnar, Yevhen B.; Hryshechkina, Tatiana S.; Keršys, Robertas
ENG: To estimate the state of the locomotive facility and work, performed by the locomotives, a system of planned and calculated indicators is used. The state of traffic safety in a locomotive facility is estimated in most cases by comparing the absolute number of traffic incidents with previous periods. Accordingly to the existing system of traffic safety analysis, the volume of work performed in the locomotive facility is not taken into account. The purpose of the research is to determine the methodology for forming a certain dimensionless indicator (or group of indicators) that will reflect the overall level of safety in the locomotive facility, taking into account the volumes of work performed by locomotives. The authors suggest the usage of the relative indicators to estimate the state of traffic safety, factoring in the volumes of transportation. As a method of research, we chose the method of the main components as the appropriate mathematical apparatus, which allows analysing the proposed indicators, characterizing the performed work and the traffic safety state with the necessary degree of informativeness. As a result, the most informative indicators and the degree of their correlation with the general index of traffic safety state were determined. Originality of the study lies in the fact that the system of indicators for the traffic safety analysis was improved; the concept of the traffic safety state index and the method of its determination using the method of the main components were improved. The practical value of the work is that we propose to use the relative indicators for estimating the traffic safety, taking into account the volumes of transportation; the ranking of the proposed indicators accordingly to the degree of their impact on the overall level of traffic safety is performed.
Simulation of Locomotive Repair Organization by the Methods of Queue Systems Theory
(Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпро, 2018) Bodnar, Borys Ye.; Ochkasov, Oleksandr B.; Bodnar, Yevhen B.; Hryshechkina, Tetiana S.; Ocheretnyuk, Maksym V.
ENG: Purpose. The article is aimed to evaluate the influence of locomotives` operation and reliability indicators on the system of locomotives repair organization in depot, using the methods of queue theory. Methodology. The article describes the locomotive repair workshop using the terms and concepts of the queue systems theory (QST). The tasks solved during simulation of the repair workshop operation are formulated, the list of initial data and simulation results is given. A graphical simulation environment Simulink was used as a software simulation tool. Findings. It was established that the main indicators of locomotive depot operation are affected by the volume of traffic, the reliability of locomotives, the rule used to select locomotives from the queue, the number of operating repair bays. The developed model of the depot repair workshop will make possible rational planning of the repair workshop`s equipment use, the human capital, the time of putting the locomotives into repair taking into account the workshop loading uniformity, as well as to improve the repair parts supply logistics. This model in a simplified form describes the repair process of the main diesel locomotive fleet, and can be supplemented depending on the repair type performed in the depot. Originality. The paper presents the locomotive repair depot as an object of the queue systems theory. The simulation model of the locomotive repair depot was developed. It allows analyzing the influence of various factors on the system of locomotives` repair organization in the depot. Practical value. The obtained results make it possible to determine the influence of locomotives` operation and reliability indicators on the organization of the locomotive repair depot operation. In further studies, the developed model can be used to improve the system of repair organization on the railway network when introducing new series of locomotives and changing the strategy of their maintenance.
Track Circuits Adjusting Calculation Method Under Current Influence Traction Interference and Electromagnetic Compatibility
(IOP Publishing, 2020) Razgonov, S. A.; Kuznetsov, Vitaliy N.; Zvonareva, Olga V.; Chernikov, D.
EN: The problem of railway transport electromagnetic compatibility automation systems in recent years has been aggravated by the use of power frequency converters in electric transport drives, which significantly increase the efficiency of traction characteristics of 3-phase electric engine. However, estimate relevant harmonic levels in the frequency range used in track circuits of railway automation and telemechanic systems. The paper provides theoretical justification for practical measurements of interference. It is shown, that the interference coefficients monotonically increase in the following cases: 1) increase in the value of the harmonic frequency; 2) increase in the propagation constant, taking into account the supports resistance of the contact network; 3) increase in the circuits track length. Operating frequencies of tonal track circuits up to 800 Hz, the interference increase rate in given length of the rail circuit slows down. The increase in interference coefficients depending on the mentioned factors is explained by the fact that with current part growth of the harmonic flows from the traction substation through the earth increases and thereby creates currents asymmetry of the track circuits.
Автоматизований комплекс діагностування реле залізничної автоматики
(Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпропетровськ, 2012) Бондаренко, Борис Маврович
UK: Запропоновано вимірювальний діагностичний комплекс для автоматизованого діагностування електромагнітних реле залізничної автоматики першого класу надійності. Наведено способи визначення їх механічних параметрів, що дозволяє виключити людський фактор із контролю, підвищити надійність приладів залізничної автоматики й безпеку руху залізничного транспорту.
Адгезійна міцність електроосаджених металевих плівок з металевими підкладками
(Дніпровський національний університет ім. Олеся Гончара, Дніпро, Україна, 2023) Штапенко, Едуард Пилипович; Воронков, Євген Олегович; Заблудовський, Володимир Олександрович; Титаренко, Валентина Василівна; Краєва, Віолетта С.; Кузнецов, Віталій Миколайович
UKR: У роботі розглянуто адгезійну міцність електроосаджених покриттів нікелю, заліза, міді та цинку на мідній та сталевій підкладках. Для визначення теоретичних значень адгезійної міцності запропоновано теоретичний підхід до визначення адгезійної міцності на межі метал-метал. Авторами на основі аналізу механізму адгезії і природи контактної взаємодії отримано аналітичний вираз для розрахунку значень адгезійної міцності для певних пар металів, проте знаходження точного значення ряду величин, що входять у цей вираз, наприклад, питомої енергії зв'язку та модуля пружності, становить великі труднощі. Розрахунок енергії взаємодії атомів покриття та підкладки проводили за методом теорії функціоналу густини. У результаті було отримано теоретичні значення адгезійної міцності електроосаджених покриттів нікелю, заліза, міді та цинку на мідній та сталевій підкладках, які добре узгоджуються з експериментальними значеннями адгезійної міцності. Однак, існуючі розбіжності між теоретичними та експериментальними даними викликані певними труднощами знаходження питомої енергії зв'язку та модуля пружності, які пов'язані зі складністю моделювання реальної структури як плівки, так і підкладки. Пошуки вирішення цих питань стануть предметом подальших досліджень.