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FRICTION AND ELECTRIC-CONTACT CHARACTERISTICS OF MATERIALS FOR ELECTRICAL CONNECTIONS AT ELEVATED TEMPERATURES
Authors: A.F. GUSEV, V.V. IZMAILOV,
Abstract: The paper describes the results of an experimental study of friction and electrical contact characteristics of the four most common materials for electrical contacts. The studies were carried out on a friction machine of the HP type (horizontal plane) according to the scheme of the end friction of the same materials with a reciprocal overlapping coefficient tending to zero at temperatures from 20 up to 150 °C. The experimental dependences of the friction coefficient f and the contact electrical resistance R on temperature in static and sliding friction are presented. Experiments have shown that at elevated temperatures surface oxide films have a decisive influence on the operational characteristics of the studied electrical contact materials. It is established that the experimental results are in good agreement with the previously obtained data on the parameters of the specific friction force, thickness and strength of oxide films for the studied materials.
Keywords: friction, coefficient of friction, contact electrical resistance, temperature, oxide films.
ASSESSMENT OF MAGNETOSTRICTIONAL CHANGES IN THE SURFACE OF A TRIBOUNIT FROM MAGNETOPLAST
Authors: O.O. NOVIKOVA, A.N. BOLOTOV, V.V. NOVIKOV,
Abstract: The effect of magnetostrictive change in the surface topography of polymer composite material under the action of a magnetic field has been revealed and studied in this work. It is established that when powder of magnetostrictive material TeFe2 with linear magnetostriction λs = 2 ⋅ 103 is used as a magnetic filler, the change in the arithmetic mean deviation of the profile is 5...20 %. It is shown that the change of the profile smoothing height is equal to 5 ⋅ 10–8 μm. In absolute values the change of surface microgeometry is tens of nanometers. The integral topography change on a large-area magnetoplast surface was evaluated by measuring the gas leakage rate through the magnetoplast-counterbody contact. The magnetostrictive nature of the surface topography change in a magnetic field was confirmed. It is emphasized that the magnitude of the effect increases with increasing field and depends on the magnetic structure of the material, i.e., it is determined by its composition, concentration, size, and orientation of the microdisperse magnetic filler.
Keywords: magnetoplasts, magnetic friction units, magnetostrictive effect, linear magnetostriction, friction control, friction, surface roughness.
STIFFNESS LINEARIZATION AND ERROR ESTIMATION OF A NUMERICAL MODEL OF A CABLE SHOCK DAMPER WITH SPATIAL LOAD PERCEPTION
Authors: S.V. DORONIN, E.M. REIZMUNT
Abstract: The difficulties arising at analytical calculation of shock absorbers with nonlinear characteristics and spatial perception of loads are noted. The difficulties of numerical simulation of the cable for the analysis of mechanical behavior of shock absorbers related to the structural complexity and dimensionality of the problem are considered. A technically sound approach to the construction of a linearized numerical model of a tether shock absorber based on experimental stiffness estimates is developed. This approach allows to reduce the dimensionality and requirements to computational resources due to simplification of the tether structure. It is emphasized that the adequacy and the possibility of using the obtained numerical model of the cable shock absorber for preliminary simplified calculations of shock absorber systems with subsequent experimental testing and refinement of the results are based on the analysis of the numerical model error.
Keywords: cable shock damper, static calculation, finite element model, nameplate load diagrams, experimental stiffness estimates, cable, linearization.
MODELING THE DESTRUCTION OF AN ADHESIVE CONTACT
IN A MAGNETIC FIELD
Authors: A.N. BOLOTOV, G.B. BURDO,
Abstract: The paper presents a new model of adhesive wear of surfaces when a magnetic field is applied. It is proposed to take into account magnetostatic forces acting in the process of separation of wear particles. It is emphasized that at the qualitative level the model agrees well with the experimental results. It is noted that the obtained results can be used to predict the properties of tribojoints operating in magnetic fields.
Keywords: magnetic field, adhesive wear.
SHAFT WITH KEYWAY INSTALLATION
ON THE CENTERS OF THE MACHINE
Authors: A.P. ARKHAROV
Abstract: An analysis of known methods and technological means for shaft installation on the centers of metal-cutting machines is presented. The essence of the developed installation method is outlined, in which the transmission of torque from the spindle to the shaft is ensured without fixation the shaft. The device and operating principle of the designed jaw chuck are disclosed. Comparative analyzes of the designed method and the chucks with similar known solutions were carried out. The development originality and the achieved technical result are reflected.
Keywords: shaft, installation, keyway, method, thrust centers, jaw chuck, surface quality.
METHOD FOR DETERMINING THE LOAD ON DOUBLE WHEEL TRAVEL
OF PEAT TRANSPORT AND TECHNOLOGICAL MACHINES
Authors: А.L. YABLONEV, A.A. ALEKSEEV
Abstract: It is noted that the transition of the absolute majority of peat mining companies to the use of tractors and machines on pneumatic wheels has identified a pronounced problem of passability of equipment on soils with reduced bearing capacity. One of the ways to solve this problem is to double wheels to increase both the perimeter and the area of the wheel contact with the peat deposit. It is emphasized that for a reasonable «retrofitting» of all machines it is necessary to correctly calculate the loads on the twin wheel arrangement. At the moment such methodology is very approximate and conditional, implying equality of loads on both wheels in the block. At the same time the experience of pneumatic wheeled vehicles operation, especially on paved roads, shows that inner wheels wear out much faster than outer wheels, and this indicates greater loading of inner wheels. The methodology for approximate calculation of loads on both wheels in the block confirming this conclusion is presented.
Keywords: peat deposit, pneumatic wheel travel, double wheel, bending moment, loads, diagram, transport vehicle.
THE CHOICE OF RATIONAL STRUCTURE, GEOMETRIC
AND OPERATING PARAMETERS OF A CLEANING COMBINE
FOR DREDGING THIN COAL SEAMS
Authors: O.E. SHABAEV, E.Yu. STEPANENKO, P.P. ZINCHENKO
Abstract: The physics of the process of loading of rock mass separated by auger actuators of small diameter is disclosed. Regression dependences of exponential type of power, specific energy consumption of loading as a function of auger working width and speed of machine movement are established. On the basis of the performed experimental and theoretical studies the methodology and mathematical model of optimization of the structure and parameters of shearers under the given mining-geological and mining-technical conditions of operation are developed. It is noted that rational values of geometrical and mode parameters and structure of the shearer will provide growth of technical productivity in 1,1...2,1 times and reduction of power and specific energy consumption of destruction and loading in 1,3...1,5 and 1,3...2,3 times respectively.
Keywords: coal combine, thin coal seams, small diameter shearer, web width of the shearer, loading capacity, coal circulation, optimization, work efficiency.
ANALYSIS OF THE PERFORMANCE OF OPERATION
OF A ROLLER CHUTE WITH A SCREW INTENSIFIER
Authors: S.M. KOCHKANYAN, A.V. KONDRATYEV
Abstract: Using a three-factor experimental design on a test bench of a roller screen with a screw intensifier, regression equations were obtained that describe the influence of the kinematic parameters of the device and the supply of gravel to the chute on the efficiency of material separation and the specific productivity of sifting the fine fraction. The graphical dependences of screening efficiency and specific productivity on a roller chute on changes in the rotation speed of shafts with disks and on the screw rotation speed are presented. The influence of changes in the amount of material supply on the specific productivity of a roller screen is considered for the entire range of varying the rotation speed of shafts with disks and the speed of rotation of the screw. For maximum gravel supply, rational operating parameters of the chute shafts and auger intensifier were determined, ensuring high separation rates of the stone material.
Keywords: roller chute, auger intensifier, shaft and auger rotation speed, screening efficiency, gravel supply, specific productivity, sifting, stone material, rational device.
INVESTIGATION OF CHANGES IN THE MECHANICAL PROPERTIES
OF SURFACES OF RESTORED PARTS OF PEAT MACHINES
Authors: I.V. GORLOV
Abstract: The results of investigation of changes in mechanical properties of surfaces restored by plastic deformation using adjacent surface are presented. It is noted that this method of restoration has a number of advantages over traditional methods of restoration of worn surfaces and can be used in the repair of scarce parts of peat machines. To estimate the change of mechanical properties of the surfaces restored by plastic deformation, their microhardness has been investigated. For the investigated materials it is established that there are no significant changes in mechanical properties of the restored surfaces.
Keywords: peat machines, repair, restoration, plastic deformation, mechanical properties.
CREATION OF AUDIO ALARM MODULES
FOR CONVEYOR STATE MONITORING SUBSYSTEMS
IN THE PEAT-BASED MIXTURE PRODUCTION
Authors: O.L. AKHREMCHIK, I.I. BASULEV
Abstract: The results obtained in the course of development of sound signaling modules of control systems for production of peat-based mixtures are presented. The tasks solved in the course of monitoring, signaling and control of technological conveyors are highlighted. An example of the functional scheme of automation of the conveyor drive for peat feeding is given and its states are defined. A mathematical description of sound tones for the operator with the introduction of classes of states, signals and reactions to the signal is proposed. It is noted that the algorithm of signal formation includes the choice of signal type and parameters by production rules. The priority of the sound signal is considered as one of the parameters. It is emphasized that the correction of parameters is based on the estimation of the operator's reaction to the signal; the addition of variation to the basic frequency of sound leads to a change in the signal spectrum when estimating the reaction time and operator's errors.
Keywords: module, parameter, class, conveyor, beep, alarm, system, reaction, frequency.
CONSTRUCTION OF AN ALGORITHM FOR CONTROLLING
THE FINAL STATE OF A FUZZY DYNAMICAL SYSTEM
Authors: V.V. BOROVIK, I.A. EGEREVA, P.M. SMIRNOVA
Abstract: Algorithms for finite state control of a fuzzy dynamic system are developed. For this purpose, a control system in which the state space of the system is a compact metric space is considered. The control space of the considered system is also a compact metric space. To construct these algorithms, the evolution of the system has been described as a fuzzy relation represented in the product of the control and state spaces of the system. This relation is given by a fuzzy set with its corresponding membership function. In accordance with the Bellman optimality principle, a search for the elements of the control sequence that allow to obtain the maximum realization of the fuzzy objective has been performed.
Keywords: fuzzy process, decision making, algorithm, Bellman equation.
FORECASTING ALGORITHM
OPTIMAL INVENTORY MANAGEMENT
IN THE ENTERPRISE
Authors: V.V. BOROVIK, D.A. KOKOVKIN, P.M. SMIRNOVA
Abstract: The paper considers the improvement of the process of purchasing goods, which leads to a decrease in production costs, as well as to an increase in profits of an industrial enterprise. During the data analysis, an algorithm was created that determines the ideal quantity of goods. It is emphasized that this algorithm will significantly improve the quality of supplies and production, reduce the cost of warehousing and product wear. It is noted that it is based on the principle of continuation of trajectories, which reduces the forecasting task to an appropriate sequence of linear programming tasks.
Keywords: the task of forecasting, the principle of constructing trajectories, the algorithm.