Problems of Tribology = Проблеми трибології - 2021 рік
Постійне посилання зібрання
Переглянути
Нові надходження
Документ Нeat and mass transfer models at boundary lubrication to determine the transition temperatures(Хмельницький національний університет, 2021) Dykha, O.; Staryi, A.; Диха, О.В.; Старий, А.Л.At present, kinetic and thermodynamic methods for assessing the lubricating effect of oils are being increasingly developed. At the limit friction, the reduction of friction and wear of surfaces is due to the ability of the lubricant to form layers of adsorption or chemical origin on the surface. Analytical models of transition temperatures and wear in the limit lubrication mode must be used to mathematically describe the processes in the subsystems and the transition between them. The Fourier equation of thermal conductivity is accepted as the basic calculated dependence. It is assumed that the process of heat propagation under the conditions of formation of lubricating films is not Markovian, i.e. the magnitude of the heat flux is determined by the entire "history" of heat transfer in a certain elementary volume. The equation of motion of a lubricating film over the surface of a body that is being lubricated is obtained from the equation of motion for a Newtonian continuous medium. As a result, nonlinear heat and mass transfer models are obtained to determine the transition temperatures in the formation of boundary lubricating films in the concept of structural-thermodynamic approaches to describe the processes of boundary lubrication of surfacesДокумент Research of the impact of carbon content in the auger material on its wear during dehydration in the solid waste garbage truck through regression analysis(Хмельницький національний університет, 2021) Bereziuk, O.V.; Savuliak, V.I.; Kharzhevskyi, V.O.; Osadchuk, A.A.; Березюк, О.В..; Савуляк, В.І.; Харжевський, В.О.; Осадчук, А.А.The article is devoted to the study of the influence of carbon content in the auger material on its wear during dehydration of municipal solid waste in the garbage truck. Using the method of regression analysis, the hyperbolic regularities of screw wear depending on the carbon content in its material for different values of the friction path were determined. Graphical dependences of auger wear were constructed, depending on the carbon content in its material for different values of the friction path, which confirms the sufficient convergence of the obtained patterns. Carrying out additional regression analysis allowed to obtain the pattern of wear of the auger, depending on the carbon content in its material and the friction path, which established the following. After two weeks of operation and wear of the auger during the dewatering of solid waste in the garbage truck, increasing the carbon content in the auger material from 0.2% to 2.1% leads to a decrease in the energy intensity of dehydration of solid waste from 19.6% to 4.4 %, which makes the process of dehydration in the garbage truck cheaper. The graphical dependence of the reduction of energy consumption of dehydration of solid household waste due to increased carbon content in the auger material during its two-week wear is presented. The practicality of further research is to determine the rational material of the auger and ways to increase its wear resistance.Документ Hydrogen nitrogening in great discharge with AC power(Хмельницький національний університет, 2021) Stechyshyna, N.M.; Stechyshyn, M.S.; Martynyuk, A.V.; Gladkiy, Ya.M.; Стечишина, Н.М.; Стечишин, М.С.; Мартинюк, А.В.; Гладкий, Я.М.The paper substantiates and experimentally shows the possibility of anhydrous nitriding in a glow discharge (BATR) with AC power supply (AC), as well as the possibility of switching the shape of pulses, changing their polarity, which is solved by introducing a glow discharge nitriding device with a power source alternating current of a given frequency. The analysis of the results of metallographic studies of the modified layer indicated the presence of a more uniform gradient of hardness in depth (gradient decreased by 1.7 - 3.5 times), which increases the wear resistance of parts and quality indicators of strengthening parts while reducing processing costs and installation costs. At BATR in CCR with supply of current of industrial frequency the installation for realization of process becomes cheaper. The latter factor will contribute, among other aspects, to the wider introduction of BATR technologies. The use of alternating current affects the course and results of nitriding, as periodic changes in the polarity of the electrodes of the chamber contributes to the cleaning of the surface from the adsorption layer, which positively affects the nature of nitrogen saturation (gradient of microhardness times), contributes to a significant change in the phase composition of the surface modified layer and allows to expand the technological capabilities of nitriding in the direction of obtaining the required performance characteristics of working surfaces, in particular tribological characteristicsДокумент Influence of lubrication on the friction and wear of car rolling bearings(Khmelnytskyi National University, 2021) Dykha, O.; Makovkin, O.; Posonsky, S.The goal of the work is to develop computational and experimental approaches to determine the wear resistance of friction units with internal contact of cylinders with slip. The scientific novelty consists in taking into account the slip for calculating the friction path and the wear of the cylinders with internal contact and the proposed method for identifying the parameters of the wear law based on the test results. Practical value is the proposed methods to account load, slip and lubrication conditions on the resource for the design of friction units. The dependences for determining the friction path for internal rolling of cylinders have been considered. The design of an experimental setup for studying friction and wear of cylinders with slip has been proposed. Experimental studies have been carried out: paths of friction; wear of surfaces both with a key and without a key; the effect of lubricants on wear has been studied. The form of the wear model is proposed to determine the effectiveness of methods for increasing wear resistance. The method for determining the parameters of the wear law has been implemented based on the test results. The results show the efficiency of copper powder as an additive to a lubricant. It has been established that the wear of cylinders with a key is greater than the wear of cylinders without a key due to different friction paths. A practical example of determining the wear of a car hub shaft using the wear patterns is presented.Документ Regression analysis of the influence of auger surface hardness on its wear during dehydration of solid waste in a garbage truck(Khmelnytskyi National University, 2021) Bereziuk, O.V.; Savulyak, V.I.; Kharzhevskyi, V.O.The article is dedicated to the study of the influence of the surface hardness of the auger on its wear during dehydration of solid waste in the garbage truck. Using the method of regression analysis, the logarithmic dependencies of auger wear depending on the hardness of its surface for different values of the friction path are determined. Graphical dependences of augur wear depending on the hardness of its surface for different values of the friction path are made up, and it confirms sufficient convergence of the obtained dependencies. Carried out additional regression analysis allowed to obtain the dependence of wear of the auger depending on the hardness of its surface and the friction path, which showed that during two weeks of operation and wear of the auger during dehydration of solid waste in the garbage truck increasing the surface hardness of the auger from 2310 MPa to 10050 MPa reducing the rate of growth of energy consumption of solid waste dehydration from 16.7 % to 1.5 %, and, consequently, to reduce the cost of the process of their dehydration in the garbage truck. The graphical dependence of the reduction of energy consumption of dehydration of solid household waste due to the increase in the hardness of the auger surface during its two-week wear is presented. It was established the expediency of further research to determine the rational material of the auger and ways to increase its wear resistance.Документ Influence of the parameters of hydrogen nitrogen nitrogen in a glow discharge on tribological and physico-chemical properties of steel 40X(Khmelnytskyi National University, 2021) Stechishina, N.M.; Stechishin, M.S.; Martynyuk, A.V.; Lukianyuk, N.V.; Lyukhovets, V.V.; Bilyk, Yu.M.One of the modern and effective methods of hardening metals is nitriding in a glow discharge in ammonia or in an anhydrous medium (nitrogen + argon) - BATR. This paper presents the results of experimental studies comparing the results of tribological and physicochemical properties of hardened surfaces obtained by nitriding with autonomous and interconnected BATR modes. The complex of traditionally fixed values of operating parameters (temperature, composition of the gas mixture, pressure and saturation time) without taking into account energy characteristics (voltage, current density and specific discharge power) significantly reduces the technological capabilities of BATR to achieve the necessary physicochemical properties of metal surfaces specified by conditions exploitation. Taking into account the energy characteristics of BATR, a significant reduction in the energy consumption of the nitriding process is achieved. The energy levels of the main subprocesses are significantly different: the formation of nitrides occurs at low energies, surface sputtering occurs at high voltage values, and nitrogen diffusion occurs at increased current density values. In cases where the energy of the flow is insufficient, either a glow discharge may not occur at all, or with a lack of voltage, the nitride ball on the surface is not sprayed and it acts as a barrier that prevents the diffusion process into the inner layers of the metal, which leads to low physicochemical and, correspondingly, tribological indicators of nitrided balls. The quantitative ratio between them and the required operational properties of the metal, respectively, can be achieved only through an independent combination of the energy and operating characteristics of BATR.Документ The influence of auger wear on the parameters of the dehydration process of solid waste in the garbage truck(Хмельницький національний університет, 2021) Bereziuk, O.V.; Savulyak, V.I.; Kharzhevskyi, V.O.; Березюк, О.В.; Савуляк, В.І.; Харжевський, В.О.The article is dedicated to the study of the influence of auger wear on the parameters of the dehydration process of municipal solid waste in the garbage truck. An improved mathematical model of the drive operation of dehydration of solid waste in the garbage truck is proposed, which takes into account the wear of the auger and allowed to numerically determine the dynamics of the drive during start-up. It was also established that increasing wear of the auger, the pressure of the working fluid at the inlet of the hydraulic motor rises, and the angular velocity and speed of the auger is significantly reduced. The research of this mathematical model was carried out using the numerical Runge-Kutta-Felberg method of the 4th order with a variable integration step. By means of the method of regression analysis, the power dependencies of the change of nominal values of pressures at the inlet of the hydraulic motor, angular velocity and speed of rotation of the auger from the value of its wear are determined. The last-mentioned dependence defines the detuning from the optimal speed of the auger during its wear and is used to determine the energy consumption of dehydration of solid waste, taking into account the wear of the auger. It is established that the wear of the auger by 1000 m leads to an increase in the energy consumption of dehydration of solid waste by 11.6%, and, therefore, also leads to an increase of the cost of the process of their dehydration in the garbage truck. It was also established the expediency of further research to determine the appropriate material of the auger and the ways to increase its wear resistance.Документ Durability of working bodies of soil-cultivating machines strengthened by composite electrolytic coatings (CEC)(Хмельницький національний університет, 2021) Stechyshyn, M.S.; Kornienko, A.O.; Stechyshyna, N.M.; Martynyuk, A.V.; Tsepeniuk, M.I.; Herasymenko, V.O.; Стечишин, М.С.; Корнієнко, А.О.; Стечишина, Н.М.; Мартинюк, А.В.; Цепенюк, М.І.; Герасименко, В.О.The task of this work is to find the optimal ratio between the size of the particles of silicon carbide and their volumetric content in the nickel matrix to provide maximum characteristics of strength and wear resistance of the working bodies of soil-processing machines. The article investigates the processes of forming complex electrolytic coatings (CEC) on a nickel basis with particles of the filler of various sizes of silicon carbide (SIC). It has been established that the formation of a sicle size sicle and SiC5 is carried out on a vertical, and all other particles in a horizontal cathode. The volumetric content of SICnano and SiC5 particles in nickel reaches a maximum of about 10%, and SiC100 – 46 %. Cap with particle size 28/20 and 50/40 μm allow you to get the most wear-resistant coatings. In this case, the coating with particles 28/20 μm have higher wear resistance, but coating with particles 50/40 μm are more technological when they are formed. The size of the filler particles has a significant effect on the tribological characteristics of the CEP, namely wear resistance and friction coefficient. It has been established that the highest wear resistance and the smallest friction coefficients are characterized by coatings having as a filler of fractions 28/20 and 50/40 μm. Tribological studies show the promise and efficiency of the CEP to increase the wear resistance of the working bodies of soil-cultivating machines.Документ Regularities of the influence of submicron ceramic powders TiO2, AlN, Cr2O3 on the tribological properties of a friction material(Хмельницький національний університет, 2021) Leshok, A.B.; Dykha, A.V.; Лешок, А.В.; Дыха, А.В.Friction units for automotive and special vehicles are designed to operate under boundary friction conditions. Modern vehicles contain friction assemblies that use friction materials. Currently, friction materials are actively used: based on thermosetting resins; pulp and paper-based materials; sintered powder materials; materials of carbon or carbon composition; materials with a ceramic matrix. The development of a unified understanding of the effect of the size and chemical nature of ceramic additives on the processes occurring in a friction material during friction is very important and can be obtained both on the basis of experimental and theoretical studies. The paper presents the results of a study of the effect of submicron TiO2, Cr2O3, AlN powders with a size of 0.2-0.5 microns on the tribotechnical properties of a frictional material based on copper intended for operation under boundary friction conditions. It was found that when using the addition of Cr2O3 powder, the greatest increase in the value of the friction coefficient is noted - from 0.042 to 0.082, a slightly smaller increase in the friction coefficient is shown by the use of AlN and TiO2 defects - 0.042-0.074 and 0.042-0.060, respectively. The least wear of the friction material was obtained when using 3.0 vol. % aluminum nitride additive - 2.1 microns / km. Increasing the addition of any of the submicron powders by more than 7 vol. % leads to a significant decrease in wear resistance. This is due to the formation on the surface of the friction material of a modified layer containing ceramic particles and the metallic phase of the friction material. For the friction material, an unstable value of the friction coefficient and increased wear were recorded.