Перегляд за Автор "Pihnastyi, Oleh"
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Документ Development of a Method for Generating Material Input Flow for Transport Conveyor Using Experimental Data(CEUR Workshop Proceedings, 2023) Pihnastyi, Oleh; Sobol, Maksym; Burduk, AnnaThis work is devoted to the development of a method for generating values of the input material flow of a transport conveyor based on experimental data. The experimental data are represented by a single realization of the material flow for a sufficiently large observation time interval. The statistical characteristics of the implementation of the input material flow are studied. To determine the values of the correlation function, the numerical integration method was used. To analyze statistical characteristics, dimensionless parameters are introduced that can be used to construct similarity criteria for input material flows. When constructing the generator of the input material flow, the canonical expansion of the random process in orthogonal functions is used. This decomposition allows transformations to be carried out over a stochastic input flow of material. It is assumed that the implementation of the input material flow is formed for the steady state of material extraction. As a zero approximation when constructing generators of the input material flow values, it is stipulated that random measurements in the canonical expansion have a normal distribution law. Orthogonal functions are represented by a normalized Fourier series. It is shown that centered random variables of the canonical expansion have dispersion values that are defined as expansion coefficients of the correlation function in a Fourier series. Analysis of the generated material flow realization shows that its values have a distribution close to the normal distribution. An example of realization using a random value generator for the input material flow is presented. The accuracy of the realization is determined by the number of terms in the Fourier series expansion and the accuracy of the numerical integration method.Документ Method for Determining Statistical Characteristics of Input Material Flows of Transport Conveyor(2023) Pihnastyi, Oleh; Sobol, MaksymThis paper is devoted to the study of the statistical characteristics of the experimental values of the material flow entering the input of a conveyor-type transport system. The paper considers the statistical analysis of the input non-stationary stochastic material flow, represented as a superposition of non-stationary deterministic and stationary stochastic material flow with ergodic properties. The problems of typification of the empirical input material flow for modern mining enterprises are considered, taking into account the technical and technological factors that characterize the method of extracting the material. The results of the work are of theoretical and practical interest for building transport conveyor models, considering the stochastic nature of the input material flow, and can be used to improve the efficiency of algorithms for optimal control of the transport conveyor material flow.Документ Modelling the dynamics of production line control systems in the context of technological safety(Akademia Pomorska, 2019-06-14) Pihnastyi, Oleh; Khodusov, ValeryThe report analyzed the multi-section conveyor systems and made a forecast of technological accidents of transport systems. The causes of technological accidents are shown.Документ Using the asymptotic approximation of the maxwell element model for the analysis of stress in a conveyor belt(ЧП "Технолог. центр", 2021) Pihnastyi, Oleh; Cherniavska, SvіtlanaThe features of the propagation of dynamic stresses in a conveyor belt, the material properties of which correspond to the Maxwell element model, are considered. Analytical expressions are presented for calculating the dynamic elastic modulus, the loss modulus, and the angle of technical loss depending on the frequency of longitudinal oscillations in the belt of an extended transport conveyor. To analyze the dynamic stress propagation process, dimensionless parameters are introduced that characterize the specific features of the viscoelastic process in a conveyor belt, the material properties of which correspond to the Maxwell element model. The transition to the dimensionless Maxwell element model is made and the analysis of the relationship between stress and deformation of a conveyor belt element for extremely large and small values of dimensionless parameters is made. The substantiation of the scope of the Maxwell element model is given. It is shown that at sufficiently high frequencies of longitudinal stress oscillations in a conveyor belt, at which the oscillation period is much less than the characteristic oscillation decay time, the relationship between stress and deformation of the conveyor belt element corresponds to Hooke’s law. A qualitative analysis of the relaxation time was carried out for a conveyor belt material, the properties of which correspond to the Maxwell element model. The analysis of the propagation of dynamic stresses in the conveyor belt for the characteristic operating modes of the transport conveyor is carried out. The conveyor operating mode with a constant deformation rate of the belt element; the mode in which a constant load is suddenly applied to the belt element; the conveyor operating mode with an instantly applied load to the belt element was investigated. It was determined that in cases where the characteristic process time significantly exceeds the stress relaxation time in the conveyor belt or the longitudinal oscillation period is much less than the stress relaxation time in the conveyor belt, the Maxwell element model can be replaced with a sufficient degree of accuracy by the Hooke element model