No abstract

The definition of the quality factor of the tribosystem has been further developed, which, unlike the known one, takes into account not only the geometric dimensions of the tribosystem, thermal diffusivity of triboelement materials, lubricating medium and deformation propagation rate in the surface layers of the material, but also the function of changing the rheological properties of the surface layers of materials during running-in and their increase during running-in. Theoretical studies have established that three parameters have the maximum effect on the quality factor: sliding speed, roughness of friction surfaces and lubricating medium. Experimental studies have established the relationship between the value of the quality factor, wear rate and coefficient of friction during steady-state operation of tribosystems. It has been shown that an increase in the figure of quality factor reduces the above parameters, and the criterion itself Qmax is a measure of the potential of the tribosystem adapt to the operating conditions.

In the work, a methodological approach to obtaining mathematical models was further developed, which describe the functioning of tribosystems in stationary and transient modes under boundary lubrication conditions.The structural identification of the tribosystem as an object of modeling the functioning of tribosystems in the conditions of boundary lubrication is performed. It is established that the operation of tribosystems is described by a third-order differential equation and, in contrast to the known ones, takes into account the function of changing the quality factor of the tribosystem during running-in. It is shown that the nature of the functioning of tribosystems under conditions of ultimate lubrication depends on the gain and time constants included in the differential equation. It is shown that the coefficient К1 takes into account the degree of influence of the input signal (load, sliding speed, tribological characteristics of the lubricating medium), on the value of the output signal (quality factor of the tribosystem). Coefficient К2 takes into account the magnitude of the change of the output parameters (volumetric wear rate and friction coefficient) when changing the values of the input parameters (load, sliding speed, quality factor of the tribosystem. Coefficient К3 takes into account the degree of influence of the input signal on the restructuring of the material structure in the surface layers of the triboelements.The time constants of the tribosystem characterize the inertia of the processes occurring in the tribosystem, during running-in, or during changes in operating modes. Increasing the time constants makes the process less susceptible to changes in the input signal, the running-in process increases over time, and the tribosystem becomes insensitive to small changes in load and slip speed. Conversely, the reduction of time constants makes the tribosystem sensitive to any external changes.

The purpose of this work was to develop a criterion for estimating the quality factor of the tribosystem and to assess its effect on wear rate, friction coefficient and run-in time. The basis of the methodological approach when developing a criterion for the quality of the tribosystem is the parameters that take into account the construction of the tribosystem, the thermal diffusivity of materials and the loading conditions of the tribosystems.The definition of the quality of the tribosystem has been further developed, which, unlike the known one, takes into account the geometric dimensions and kinematic scheme of the tribosystem, the thermal diffusivity of materials and the rate of propagation of deformation in the surface layers of the triboelement materials during their contact interaction. Theoretical and experimental studies established the relationship between the quality value, wear rate and the friction coefficient in the process of running-in. It is shown that the increase in quality helps to reduce the above-mentioned parameters.The relationship between the running-in time and the quality value is established. It is shown that the process of running-in can be controlled. To reduce the running-in time, it is necessary to reduce the sliding speed during the transient process and to increase the tribological properties of the lubricating medium. The presented theoretical and experimental studies allow us to state that the quality of tribosystems Q can be a measure of the potential ability of the tribosystem to adapt (adapt) to operating conditions, providing the maximum resource.

The method of diagnosing various constructions of tribosystems by acoustic emission method is developed in the work. The development of the methodology is based on the following assumptions. The activity of acoustic emission during the operation of the tribosystem will depend on the rate of deformation of materials on the spots of actual contact. The total acoustic signal from the friction zone is formed as a result of the interference of the primary acoustic signals from the spots of actual contact with the friction surface, which correspond to the coherence condition. Based on these assumptions, the expression for calculating the informative frequencies that will be generated by the tribosystem in the process. The method of diagnosis contains the following steps: determination of informative frequencies on which it is necessary to register amplitudes; determining the magnitude of the amplitudes that carry the maximum information; distribution of the general acoustic signal on clusters and establishment of functional communication of values of a peak factor of clusters with values of coefficient of friction, speed of wear and time of running-in of tribosystems in an online mode. The use of the developed technique will increase the robustness of the method of diagnosing tribosystems and identify surface processes during wear.