Khmelnytskyi, Ukraine
Khmelnytskyi, Ukraine

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Dykha A.V.,Khmelnytskyi National University | Kuz'menko A.G.,Khmelnytskyi National University
Journal of Friction and Wear | Year: 2016

This article describes the calculation-experimental approach to determining friction stresses based on an experimental dependence of friction force on the displacement of compressed surfaces. As an example of the approach application, analysis of Bowden’s mechanical model of friction is presented. In the approach implementation, we use the results of Courtney-Pratt experiment. Solutions are given in the power form. © Allerton Press, Inc., 2016.


Goroshko A.V.,Khmelnytskyi National University | Royzman V.P.,Khmelnytskyi National University
Journal of Machinery Manufacture and Reliability | Year: 2016

The difficulties of design determination of the quantitative characteristics of weight, elasticity, 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 uncomplicated 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 example of five-mass rotor model. © 2016, Allerton Press, Inc.


Dykha A.V.,Khmelnytskyi National University | Kuzmenko A.G.,Khmelnytskyi National University
Journal of Friction and Wear | Year: 2015

In this work, the theory of ball wear for a four-ball wear-testing scheme is presented. The direct problem of determining the dimensions of the worn place depending on the sliding distance and the inverse problem of determining the parameters of the wear model based on the data of wear tests have been solved. Solutions have been obtained for the initial zero and nonzero contact patch and are based on the assumption of a uniform distribution of the pressures over the contact area. The examples of numerical solutions to the problem of contact wears under consideration have been provided. © 2015, Allerton Press, Inc.


Goroshko A.,Khmelnytskyi National University | Royzman V.,Khmelnytskyi National University | Pietraszek J.,Cracow University of Technology
Mechanika | Year: 2014

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.


A discrete noiseless duel is defined on the unit square; each player in the duel has a finite number of pure strategies uniformly distributed on the unit segment. The theorem on the existence of individual solutions of the discrete noiseless duel in pure strategies is proved. The construction of a program procedure for solving the discrete noiseless duel is presented. © 2011 Springer Science+Business Media, Inc.


Rebesh A.P.,NASU Bogolyubov Institute for Theoretical Physics | Kachurik I.I.,NASU Bogolyubov Institute for Theoretical Physics | Kachurik I.I.,Khmelnytskyi National University | Gavrilik A.M.,NASU Bogolyubov Institute for Theoretical Physics
Ukrainian Journal of Physics | Year: 2013

We review on and give some further details about the thermodynamical properties of the μ- Bose gas model (arXiv:1309.1363) introduced by us recently. This model was elaborated in connection with μ-deformed oscillators. Here, we present the necessary concepts and tools from the so-called μ-calculus. For the high temperatures, we obtain the virial expansion of the equation of state, as well as five virial coefficients. In the regime of low temperatures, the critical temperature of condensation is inferred. We also obtain the specific heat, internal energy, and entropy for a μ-Bose gas for both low and high temperatures. All thermodynamical functions depend on the deformation parameter μ. The dependences of the entropy and the specific heat on the deformation parameter are visualized. © A.P. REBESH, I.I. KACHURIK, A.M. GAVRILIK, 2013.


The author considers an antagonistic model of fitting cross-sectional areas of the supports of construction platform, where the total load on the platform is normalized to unity. The generalized model under study is generated by interval uncertainties as the evaluations of the normalized squares of support cross-sections. The author proves the assertions on the designer's optimal decisions in such model by overestimation of uncertainties, where the conditions of the last assertion are obtained by inducing the conditions of the two first assertions. © 2014 Springer Science+Business Media New York.


Yaretskaya N.A.,Khmelnytskyi National University
International Applied Mechanics | Year: 2014

An axisymmetric mixed problem for an elastic cylindrical punch pressed into a layer with initial (residual) stresses is solved using the linearized theory of elasticity. The analysis is performed in general form for the theory of large (finite) deformations and various theories of small initial deformations for an arbitrary elastic potential. © 2014, Springer Science+Business Media New York.


The author considers an antagonistic model of fitting cross-sectional areas of the supports of construction platform, where the total load on the platform is normalized to unity. The generalized model under study is generated by interval uncertainties as the evaluations of the normalized squares of support cross-sections. The author proves the assertions on the designer’s optimal decisions in such model by overestimation of uncertainties, where the conditions of the last assertion are obtained by inducing the conditions of the two first assertions. © 2014, Springer Science+Business Media New York.


Goroshko A.V.,Khmelnytskyi National University | Royzman V.P.,Khmelnytskyi National University
Journal of Machinery Manufacture and Reliability | Year: 2015

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 conditionality 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 stability 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 statistical algorithm for achieving a given accuracy of the solution of poorly specified systems of linear algebraic equations are developed. The results of using the offered methods for the identification of eccentricities and elastic inertial parameters in the problem of decreasing the vibroactivity of the rotor of turbine pump are given. © 2015, Allerton Press, Inc.

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