Видання зареєстровані авторами шляхом самоархівування
Permanent URI for this communityhttps://devessuir.sumdu.edu.ua/handle/123456789/1
Browse
9 results
Search Results
Item Phenomenological Theory for the Melting of a Thin Lubricant Film between Two Atomically Smooth Solid Surfaces(Pleiades publishing, 2010) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ляшенко, Яків Олександрович; Ляшенко, Яков Александрович; Liashenko, Yakiv Oleksandrovych; Metlov, L.S.A thermodynamic model is developed for the melting of an ultrathin lubricant film squeezed between two atomically smooth solid surfaces. To describe the state of lubricant, an excess volume parameter is introduced; it appears due to the chaos in the structure of a solid body induced by melting. This parameter increases with the total internal energy upon melting. Thermodynamic melting and shear melting are described. The dependences of the friction force on the lubricant temperature and the shear rate of friction surfaces are analyzed. The calculated results are compared to the experimental data. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/18092Item Periodic intermittent regime of boundary friction(Pleiades publishing, 2010) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ляшенко, Яків Олександрович; Ляшенко, Яков Александрович; Liashenko, Yakiv OleksandrovychMelting of an ultrathin lubricant film during friction between two atomically smooth surfaces is investigated using the Lorentz model for approximating the viscoelastic medium. Second-order differential equations describing damped harmonic oscillations are derived for three boundary relations between the shear stresses, strain, and temperature relaxation times. In all cases, phase portraits and time dependences of stresses are constructed. It is found that under the action of a random force (additive uncorrelated noise), an undamped oscillation mode corresponding to a periodic intermittent regime sets in, which conforms to a periodic stick—slip regime of friction that is mainly responsible for fracture of rubbing parts. The conditions in which the periodic intermittent regime is manifested most clearly are determined, as well as parameters for which this regime does not set in the entire range of the friction surface temperature. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/18091Item Феноменологiчна теорiя переривчастого режиму межового тертя(Інститут теоретичної фізики ім. М.М.Боголюбова, 2011) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ляшенко, Яків Олександрович; Ляшенко, Яков Александрович; Liashenko, Yakiv Oleksandrovych; Метлов, Леонід СеменовичПобудовано детерміністичну теорію плавлення ультратонкої плівки мастила, яку затиснуто між двома атомарно-гладкими твердими поверхнями. Для опису стану мастила введено параметр надлишкового об'єму, що виникає за рахунок хаотизації структури твердого тіла в процесі плавлення. Узгодженим чином описано термодинамічне і зсувне плавлення. Проаналізовано залежності стаціонарної сили тертя від температури мастила і швидкості зсуву поверхонь, що труться, при їх рівномірному зсуві із постійною швидкістю. В рамках простої трибологічної моделі описано переривчастий режим тертя, при якому мастило періодично плавиться і твердне. Проаналізовано вплив швидкості, температури і навантаження на переривчасте тертя. Проведено якісне порівняння отриманих результатів із експериментальними даними При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/18090Item Thermodynamics and kinetics of boundary friction(Elsevier Science Publishing Company, 2011) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ляшенко, Яків Олександрович; Ляшенко, Яков Александрович; Liashenko, Yakiv Oleksandrovych; Metlov, L.S.A deterministic theory describing the behavior of an ultrathin lubricant film between two atomically-smooth solid surfaces is proposed. For the description of lubricant state the parameter of excess volume arising due to chaotization of solid medium structure in the course of melting is introduced. Thermodynamic and shear melting are described. Dependences of friction force on temperature of lubricant, shear velocity of rubbing surfaces, and pressure upon surfaces are analyzed. Within the framework of a simple tribological model the stick-slip mode of friction, when the lubricant periodically melts and solidifies, is described. The obtained results are qualitatively compared with the experimental data. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/18088Item Self-similar phase dynamics of boundary friction(Ukrainian Journal of Physics, 2009) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ляшенко, Яків Олександрович; Ляшенко, Яков Александрович; Liashenko, Yakiv Oleksandrovych; Борисюк, Вадим Миколайович; Борисюк, Вадим Николаевич; Borysiuk, Vadym MykolaiovychThe melting of an ultrathin lubricant film confined between two atomically flat solid surfaces has been studied. The phase diagram with the domains of sliding, dry, and intermittent (stick-slip) frictions has been constructed, by taking the additive noises of stress, strain, and temperature into account. The time series of stresses have been constructed for the parameters of all the modes within the Stratonovich calculus. In the case where the temperature noise intensity exceeds much more the intensities of stress and strain noises, the self-similar mode is established during the melting of a lubricant. The multifractality of the stress time series is shown to be provided by the power-law shape of the distribution function and by the presence of correlations in the system. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/16488Item Hysteresis phenomena during melting of an ultrathin lubricant film(Pleiades publishing, Ltd, 2007) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ляшенко, Яків Олександрович; Ляшенко, Яков Александрович; Liashenko, Yakiv OleksandrovychThe influence of a deformational defect of the shear modulus on the melting of an ultrathin lubricant film was investigated in the framework of the Lorenz model used for describing a viscoelastic medium. It was established that the film can undergo both stepwise and continuous melting. Analysis of the lubricant behavior revealed that there are three modes corresponding to a zero shear stress, a Hookean portion in the loading diagram, and a plastic-flow portion. The hysteresis in the dependences of the stationary shear stress on the strain and the friction surface temperature is examined. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/16213Item Effect of correlated temperature fluctuations on the phase dynamics in an ultrathin lubricant film(Pleiades publishing, Ltd, 2007) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii VitaliiovychThe melting of an ultrathin lubricant film at friction between atomically smooth surfaces is studied with allowance for fluctuations of its temperature, which are described by the Ornstein-Uhlenbeck process. The behavior of the most probable types of shear stresses arising in the lubricant is considered, and phase diagrams for second- and first-order phase transformations (the melting of an amorphous lubricant and that of a crystalline lubricant, respectively) are constructed. It is shown that, in the former case, lubricant temperature fluctuations lead to the formation of a stick-slip friction domain separating the domains of dry and sliding friction, which is typical of first-order transitions. In the latter case, three domains of stick-slip friction arise, which mark the transitions between dry friction and metastable and stable sliding friction. As the time of correlation of lubricant temperature fluctuations gets longer, the temperature of rubbing surfaces rises to the point where sliding friction sets in. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/16210Item Melting of ultrathin lubricant film due to dissipative heating of friction surfaces(Pleiades publishing, Ltd, 2007) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ляшенко, Яків Олександрович; Ляшенко, Яков Александрович; Liashenko, Yakiv OleksandrovychMelting of an ultrathin lubricant film during friction between atomically smooth surfaces is studied. Additive noise of shear stress and strain as well as of film temperature is introduced and the phase diagram is constructed. On the diagram, the noise intensity for this temperature and the temperature of friction surfaces determine the regions of sliding, dry, and stick-slip friction. As a result of numerical analysis of the Langevin equation for various regions of the diagram, time series of stresses are constructed, which make it possible to explain the experiment on friction, in which intermittent motion is observed. Lubricant melting due to dissipa-tive heating of friction surface is considered and the experimental time dependences of friction force are interpreted. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/16209Item Phase dynamics and kinetics of thin lubricant film driven by correlated temperature fluctuations(World scientific publishing company, 2007) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ляшенко, Яків Олександрович; Ляшенко, Яков Александрович; Liashenko, Yakiv OleksandrovychThe melting of an ultrathin lubricant film is studied at friction between atomically flat surfaces. We take into account fluctuations of lubricant temperature, which are defined by the Ornstein-Uhlenbeck process. Phase diagrams and portraits are calculated for second- and first-order transitions (the melting of an amorphous and that of a crystalline lubricants, respectively). It is shown that, in the former case, a stick-slip friction domain, separating the regions of dry and sliding friction, appears. In the latter case, three domains of stick-slip friction arise, which are characterized by the transitions between dry, metastable and stable sliding friction. The increase in the correlation time of lubricant temperature fluctuations leads to increasing in the rubbing-surface temperature needed for realization of sliding friction. The stationary states, corresponding to dry, stable and metastable sliding friction, are reached as a result of damped oscillations. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/16208