Кафедра фізики і електротехніки

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https://elar.khmnu.edu.ua/handle/123456789/577

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Зараз показуємо 1 - 13 з 13

Analysis of Unbalanced Induction Motor Rotor Forces in Bearings with Clearances
(Israeli independent academy of development of science, Holon, Israel, 2024-11) Goroshko, Andrii; Zembytska, Maryna
The paper analyzes the influence of unbalanced rotor forces of induction motor on the operation of bearings with clearances. A mathematical model considering mechanical unbalance and static magnetic unbalance is developed in the paper. The results of modeling showed that the joint action of these factors leads to unstable operation mode of bearings and accelerated wear. The unbalance factor depends on the static eccentricity angle and the instantaneous value of the trunnion rotation angle. The obtained results can be used to optimize the design of induction motors and to develop methods of diagnostics of their condition.
Balancing of turbomachine rotors by increasing the eccentricity identification accuracy
(Mechanika, Kaunas, 2016) Goroshko, Andrii; Royzman, Vilen; Ostaševičius, V
The article presents the results of research aimed at improving the identification of eccentricities by ensuring the stability of solutions of linear discrete inverse problems. The results of the application of scaling factors of systems with a view to reducing their dependence are suggested. Identi-fied eccentricities imbalances and angles of their location allowed to balance the rotor turbopump unit TNA-150 and reduce the maximum deflection of the rotor shaft in the range of 2000-18000 rpm 6 times, the amplitude of vibra-tion supports - 4 times, the static tension in the material of the shaft - 3.5 times, and dynamic tension- 3 times. The use of linear filtering LSEs based on the PCA method, has sig-nificantly reduced the LSE scattering and accurately iden-tify the eccentricities of the compressor rotor of aircraft en-gine AI-20.
Construction and practical application of hybrid statisticallydetermined models of multistage mechanical systems
(Kaunas University of Technology, 2014) Goroshko, Andrii; Royzman, Vilen
The paper proposes a method of creating a hybrid statistically-determined models for structurally complex of mechanical systems. The method uses an active planned experiment , but it can significantly reduce the amount of experimental research. Hybrid statistically-determined model of aircraft defendant signal power was created. Priority factors of mechanical nature destabilizing the output power level were identified. The study solved multiple inverse problem of determining the permissible values of these factors, in which the signal power is within specifications.
Design Principles of Horizontal Drum Machines with Low Vibration
(Advances in Science and Technology Research Journal, 2021-05) Drach, Ilona; Goroshko, Andrii; Dwornicka, Renata
Using the example of washing machines using the linear theory of vibrations, the dynamics of horizontal rotary drum machines is investigated and the basic requirements for their layout are formulated to reduce vibration activity. The mathematical equations of vibrations of the multiply connected system tub-drum on elastic suspensions are compiled for main types of washing machines and centrifuges with horizontal axis of rotation. The problem is solved in a linear setting based on the Lagrange equation of the second kind. The accuracy and adequacy of the mathematical model was tested directly on a full-scale object by measuring noise, vibrations, support forces and stress distribution in individual elements and units of the washing machine in the entire range of drum rotation frequencies. Investigations of the nature of system vibrations depending on changes in the position and attachment points of elastic and damping elements were carried out using simulation in the Simulink environment. As a result of the research, the basic requirements for the layout of horizontal rotary drum machines were experimentally confirmed. Experimental verification was carried out to confirm the results obtained. It has been experimentally proven that the improvement of the experimental setup to reduce its vibration activity increases the efficiency of using direct-acting liquid autobalancers.
Experience Formulating and Solving Inverse Problems for Strength Design of Electronic Equipment
(2014-08-20) Goroshko, Andrii
The paper shows the results of formulation and solution of inverse problems for strength compounded elements electronics. Considered and studied real construction - micro-module. A parameter identification of a mathematical model, as close to the real conditions of the structure is offered. Decomposition of a mixture of probability distributions experimentally obtained values of destructive forces in the tests carried out. The tolerances of valid values of the mathematical model by solving the optimization problem are calculated. For the case where the physical and mechanical characteristics of the elements do not correspond to those found with the limits of tolerances and do not provide the structural strength, proposed some solutions to this problem. In this way, there is a selective assembly.
Increase in Solution Stability of Ill Conditioned Dynamics Problems
(Allerton Press, Inc., 2016-06) Goroshko, Andrii; Royzman, Vilen
The difficulties of design determination of the quantitative characteristics of weight, elas ticity, damping, critical frequencies of fast revolving rotors are demonstrated. It is suggested to use two approaches in order to obtain accurate and stable solutions of ill conditioned reverse problems of rotor dynamics. The first one concerns the reduction of design model size. It is shown that relatively uncom plicated design rotor models are used as they were considered the most effective and stable, and match the selected design scheme and parameter values (hardness, weights, deflections, etc.) obtained as a result of experiments or calculations. The second approach deals with statistical method of the increase of solution stability. Its efficiency was shown while identifying rotor eccentricity by the exam ple of five mass rotor model.
Metaphysical Modeling of Rotor dynamics Motor Spindle with magnetic Eccentricity
(Israeli independent Academy of development of Science, 2026-03) Goroshko, Andrii; Zembytska, Maryna
The paper presents a metaphysical model of the rotor dynamics of an asynchronous motor spindle that accounts for the effect of magnetic eccentricity. The study proposes a new approach to modeling unbalanced magnetic pull (UMP) based on a variable mutual inductance of the magnetizing circuit instead of the classical Maxwell stress tensor method. Analytical dependences between the air-gap eccentricity, magnetizing inductance, and UMP components are derived, and a modified Simscape/Simulink model of the asynchronous machine is implemented to simulate these relationships. The simulation results demonstrate the influence of magnetic eccentricity on the electromagnetic torque, stator current spectrum, and rotor speed. The proposed model provides a practical tool for diagnosing eccentricity-related faults and predicting vibration behavior in motor spindles
Modeling of Eccentric Rotor Dynamics in an Unbalanced Magnetic Field
(Khmelnytskyi National University, 2024-06) Goroshko, Andrii; Zembytska, Maryna
The paper studies the dynamics of a three-phase induction motor with squirrel cage rotor, which has eccentricity of different kinds. For this purpose, a mathematical model of oscillations of a rigid rotor with mass eccentricity, which oscillates on two elastic supports, is established. The model is further extended to take into account the forces of unbalanced magnetic pull, which arise under static and dynamic magnetic eccentricity. A simulation model in Simulink/Simscape Multibody environment is created to solve the obtained nonlinear model. The simulation of induction motor dynamics is carried out and the vibration signals are analyzed in time and frequency domain. Vib ations caused by static magnetic eccentricity occur at twice the electrical frequency. Vibrations caused by dynamic eccentricity take the form of a rotor frequency signal modulated by a low frequency depending on the rotor precession. The model can be used for vibration diagnostics of motor rotor eccentricity.
Quality and Reliability of Technical Systems: Theory and Practice
(JVE International Ltd, 2018-08) Goroshko, Andrii; Royzman, Vilen; Zembytska, Maryna
The monograph provides original approaches to the quality and reliability improvement in mechanical engineering, taking into account the functionally oriented management. The outlined studies validate the methods facilitating the increased reliability and durability of rotor systems and vibration processes. Methods for increasing the reliability and wear resistance of machine parts and units under dynamic and shock loads are considered and proposed. The issues of creation of new materials in mechanical engineering, in particular, nanostructures are studied and investigated. New quality and reliability improving methods for electronic equipment and energy systems are offered. The research also considers the issues of reliability and durability of construction materials. The monograph is intended for scientists, graduate students and professionals in the field. It may also be useful to students of technology.
Simulation of induction motor vibrations under the Influence mechanical and magnetic eccentricit
(2023-12) Goroshko, Andrii; Zembytska, Maryna
The paper analyzes the influence of unbalanced rotor forces of induction motor on the operation of bearings with clearances. A mathematical model considering mechanical unbalance and static magnetic unbalance is developed in the paper. The results of modeling showed that the joint action of these factors leads to unstable operation mode of bearings and accelerated wear. The unbalance factor depends on the static eccentricity angle and the instantaneous value of the trunnion rotation angle. The obtained results can be used to optimize the design of induction motors and to develop methods of diagnostics of their condition.
Statistical Methods for Providing the Stability of the Solutions of Inverse Problems and Their Application to Decrease Rotor Vibroactivity
(Allerton Press, Inc., 2015) Goroshko, Andrii; Royzman, Vilen
Many machine design problems relate to the class of inverse problems, whose solution is reduced to the solution of systems of linear algebraic equations. The relation between the matrix con ditionality number of such systems and solution errors is shown in this article. The application of the least square method to improve the accuracy of solutions is justified. A method for providing the sta bility of solutions of systems of linear algebraic equations based on the use of additional information by increasing the number of measurements of initial parameters is proposed. The approach and statis tical algorithm for achieving a given accuracy of the solution of poorly specified systems of linear alge braic equations are developed. The results of using the offered methods for the identification of eccen tricities and elastic inertial parameters in the problem of decreasing the vibroactivity of the rotor of tur bine pump are given.
The Heuristic Approach to the Selection of Experimental Design, Model and Valid Pre-Processing Transformation of DoE Outcome
(Trans Tech Publications, 2014) Pietraszek, Jacek; Goroshko, Andrii
The typical problem in the design of experiments methodology is to avoid the risk of obtaining predictions outside of ranges with a technological or physical sense. Such a situation occurs very often if a simple linear regression or another unbounded one is involved as a predictive model. The possible solution is to provide mappings of the outcome from the range of interest into the full range from negative to plus infinity before the linear regression is applied. The intermediate values obtained from the unbounded predictive model are re-transformed into the physical domain by the inverse transformation. The key issue is to decide if the mapping is required and –subsequently – what mapping is necessary. The author proposed a simple heuristic solution supporting this decision and tested such a solution in some examples described in this paper.
The Principal Component Analysis of Tribological Tests of Surface Layers Modified with IF-WS2 Nanoparticles
(Trans Tech Publications, Switzerland, 2015) Pietraszek, Jacek; Korzekwa, Joanna; Goroshko, Andrii
The investigation described in this paper resulted in some complicated statistical analysis. The first level was an experimental design with technological parameters as factorials input and geometrical surface layer properties as quantitative outputs. The second level was an analysis generally leading to an optimization inverse problem: what parameters result in desired surface layer properties. The principal component analysis was made to identify possibility of a dimensionality reduction and simplify the optimization. Obtained results showed that the experimental dataset is practically two-dimensional but PCA projection involves all factors into the skewed hyper-plane. This paper contains a description of the problem, obtained results, analysis and conclusions.

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