Кафедра економічної інформатики (ДМетІ)
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Browsing Кафедра економічної інформатики (ДМетІ) by Author "Monia, Andrii G."
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Item Comparative Mathematical Analysis of Transmission and Axial Disc Brakes(Український державний університет науки і технологій, Дніпро, 2024) Monia, Andrii G.; Bychkova, D. M.ENG: Purpose. A comparative study of axial and transmission disc-pad brakes. The task of the work is the theoretical determination of the braking torque and the force of pressing the pads against the disk in different braking modes, as well as the determination of the area of optimal operating modes of the indicated brakes. The methods. Comparative mathematical analysis. Findings. With equal dimensions of the two types of disc brakes and an even distribution of the braking torque between the wheel pairs, the transmission creates a greater braking torque on each of the four wheels of the traction section due to the gear ratio of the axial gearbox. Installing a disc brake on the axle of a wheel pair with a central location of the drive gear wheel allows you to change the masses of the half-axles, which means to eliminate self-oscillations that destroy the drive axle under the action of resonant torsional vibrations. The heavier the rolling stock of the train being transported, or the greater the slope of the track on the descent, the smaller the braking torque can be applied to the wheel pair, to exclude its blocking and clutch failure. The obtained results show that the smaller the moments of inertia and stiffness of the wheels, half-axles and transmission elements (gear wheels, shafts, etc.), the smaller the braking torque required to stop the locomotive on the same braking path. But the higher the speed of the train before braking, the greater the braking torque should be. Originality. The obtained results show that the smaller the moments of inertia and stiffness of the wheels, half-axles and transmission elements (gear wheels, shafts, etc.), the smaller the braking torque required to stop the locomotive on the same braking path. But the higher the speed of the train before braking, the greater the braking torque should be. Practical value. Taking into account the above-mentioned features of disc brakes, multilevel backup of brake systems of heavy mining locomotives operating on track slopes of up to 50 ‰ should be considered justified and necessary. Such locomotives should have both disc transmission brakes, as more efficient, and disc axle brakes as safer.Item Mathematical Model of Pressure and Temperature Distribution in Working Area of Mine Locomotive Disc Brake(Dnipro University of Technology, Dnipro, 2024) Monia, Andrii G.ENG: Purpose. Calculate the coordinates of the maximum temperature and the greatest pressure on the working surface for the rational parameters of the main elements of the disc brake of the mine locomotive with a multi-sector brake disc selected by mathematical modeling. The methods. To find the coordinates of the maximum temperature and the greatest pressure on the working surface of a disc brake with a multi-sector brake disc with selected rational parameters, mathematical modeling of temperature and pressure on the friction surface was carried out. Findings. On the basis of mathematical modeling, the maximum temperature and its coordinates and the greatest pressure on the working surface of a disc brake with a multi-sector brake disc were found. It is shown that the maximum temperature on the friction surface of the main elements of the disc brake with the selected parameters in specific mine conditions under the most unfavorable operating conditions will not exceed the permissible value. The originality. A mathematical model of braking of a mine locomotive with a disc brake was developed, which creates a pulsating braking moment on the axle of the wheel pair, which depends on its angular coordinate, taking into account the non-linear dependence of the coupling coefficient on the relative slip, on the basis of which the parameters of the braking moment are established, which allow to improve the braking characteristics. Practical implementation. A scientifically based engineering methodology for choosing rational parameters of the disc brake of a mine locomotive and determining the dynamic and kinematic characteristics of the drive of a mine locomotive when braking with a disc brake with a multi-sector disc has been developed. An analytical solution to the non-stationary thermal conductivity problem of finding the temperature field that occurs in the brake disc and friction linings of the disc brake of a mine locomotive when the linings are made in the form of a ring sector was obtained, on the basis of which the dependence of the relative temperature on the friction surface of the brake was found of the disk over time during cyclic braking.Item Mathematical Modeling of Rational Parameters of the Mine Locomotive Disc Brake in Computer Systems(Український державний університет науки і технологій, Дніпро, Україна, 2023) Monia, Andrii G.; Bychkova, D. M.ENG: Purpose. Determination of braking torque parameters that provide high braking performance of a mine locomotive by mathematical modeling of the braking of a mine locomotive by a disc brake that creates a pulsating braking torque. Methodology. Forced vibrations of the elements of the wheel-motor unit (WMU) of a mine locomotive in the process of braking with a disc brake are studied by the methods of differential calculus and mathematical modeling. Integration of the system of differential equations is performed by the Runge-Kutt method. Findings. A comparative analysis of a mine locomotive braking by a disc brake, which creates a constant and pulsating sinusoidal braking torque with a different number of sinusoid periods per revolution of the wheel pair, is carried out. It has been proved that the pulsating sinusoidal braking moment generated on the axle of the wheel pair equal to the sum of the constant component and the amplitude of the oscillations of the variable component multiplied by the sine of the product of the number of sinusoid periods per revolution of the wheel pair by its angular coordinate provides higher braking characteristics than the constant braking moment. It is shown that pulsating braking torque reduces the braking time and braking distance of the mine locomotive. The values of the amplitude of oscillations, which depend on the average value of the braking torque, and the number of periods of the sinusoid per one revolution of the wheelset, at which the greatest effect is achieved, are determined. Originality. For the first time, a mathematical model has been developed for braking a mine locomotive by a disc brake, which creates a pulsating braking torque on the axle of the wheel pair, depending on its angular coordinate, taking into account the nonlinear dependence of the adhesion coefficient on relative slip, on the basis of which the efficiency of a disc brake with a multi-sector disc is shown in comparison with a disc brake with a homogeneous disk under various conditions of the rail track. Practical value. The research results make it possible to determine the parameters of a disc brake with a multi-sector disc located on the wheelset axle and on the engine shaft, which provide the highest braking efficiency.Item Mathematical Substantiation of Mine Locomotive Braking Efficiency under Pulsiting Braking Torque(Dnipro University of Technology, Dnipro, Ukraine, 2023) Monia, Andrii G.ENG: Purpose. Determination of braking torque parameters that provide high braking performance of a mine locomotive by mathematical modeling of the braking of a mine locomotive by a disc brake that creates a pulsating braking torque. The methods. Forced vibrations of the elements of the wheel-motor unit (WMU) of a mine locomotive in the process of braking with a disc brake are studied by the methods of differential calculus and mathematical modeling. Integration of the system of differential equations is performed by the Runge-Kutt method. Findings. A comparative analysis of a mine locomotive braking by a disc brake, which creates a constant and pulsating sinusoidal braking torque with a different number of sinusoid periods per revolution of the wheel pair, is carried out. It has been proved that the pulsating sinusoidal braking moment generated on the axle of the wheel pair equal to the sum of the constant component and the amplitude of the oscillations of the variable component multiplied by the sine of the product of the number of sinusoid periods per revolution of the wheel pair by its angular coordinate provides higher braking characteristics than the constant braking moment. It is shown that pulsating braking torque reduces the braking time and braking distance of the mine locomotive. The values of the amplitude of oscillations, which depend on the average value of the braking torque, and the number of periods of the sinusoid per one revolution of the wheelset, at which the greatest effect is achieved, are determined. The originality. For the first time, a mathematical model has been developed for braking a mine locomotive by a disc brake, which creates a pulsating braking torque on the axle of the wheel pair, depending on its angular coordinate, taking into account the nonlinear dependence of the adhesion coefficient on relative slip, on the basis of which the efficiency of a disc brake with a multisector disc is shown in comparison with a disc brake with a homogeneous disk under various conditions of the rail track. Practical implementation. The research results make it possible to determine the parameters of a disc brake with a multi-sector disc located on the wheelset axle and on the engine shaft, which provide the highest braking efficiency.Item Pipe Production Cost Management Model Based on Graph Theory(Dnipro University of Technology, Dnipro, 2024) Toporkova, Olena A.; Lozovska, Lyudmila I.; Savchuk, Larysa M.; Monia, Andrii G.; Bandorina, Liliia M.ENG: The pipe production process is a complex dynamical system with a significant number of production operations and interconnected cost localization centres. Purpose. To develop a mathematical model of the process of handling analytical information of a pipe enterprise using graph theory for the needs of cost management at each production stage. Methodology. Technological flow charts of the production job, where the list of mandatory activities and routing of the operating process are indicated, were used to organize cost accounting by operational centres of their localization with the help of computer modelling elements, namely the graph theory. The work used a complex of research methods, including analysis and scientific synthesis of scientific and technical information; theoretical studies; methods of mathematical and computer modelling, engineering developments. Findings. The cost accounting process is represented by a directed hypergraph. Each production operation is associated with a graph vertex. Each vertex is assigned to a series of interrelated marks: type of technological operation; weight factor; the value of direct costs for the operation; the value of indirect costs for the operation; the expense factor. The initial state of the hypergraph is specified by means of its initial marking, which corresponds to the set cipher of the batch of pipes and its weight. Further execution of the marked hypergraph is performed by running the allowed vertices. Marking of the graph ends if all the information from the technological flow charts of pipe products has been used. Originality. A model of cost management by operational centres is proposed which will allow dividing the prime cost of pipes which differ according to the production technology. It is recommended to rank pipe products within each technologically similar group for an economically feasible allocation of costs between batches of pipes. The proposed process model of processing analytical information of the pipe enterprise using graph theory will allow providing data governance as for the prime cost of each individual batch of pipe products, will contribute to the improvement in the order generation procedure taking into account the acquired information, and will allow making the appropriate adjustments when making management decisions. Practical value. Calculation of expenses for production operations allows one to identify the most cost-intensive of them. Relying on the results of the calculation, the enterprise management has the opportunity to manage costs at any stage of the production process. Moreover, the model allows determining the amount of consumed metal for each production operation, which is relevant for pipe enterprises. It is appropriate to focus further scientific developments in this direction on the possibility of managing non-manufacturing cost with the help of mathematical models in economics to optimize the supply and sales activities of the enterprise.