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HARRINGTON DESIRABILITY FUNCTION APPLICATION TO THE SELECTION OF MATERIALS FOR SLIDING ELECTRICAL CONTACT
Authors: V.V. IZMAILOV, Dr. Sc., A.F. GUSEV, Cand. Sc.,
M.V. NOVOSELOVA, Cand. Sc.
Abstract: The results of a study of the frictional and electrical characteristics of the brush-collector unit of electric motors at temperatures up to 200 C are presented. The possibility of using the generalized Harrington desirability function as an integral indicator of the quality of electrical brush composite materials is shown. The generalized desirability function for copper-based electrical brush materials is calculated, taking into account the main operational characteristics of the contact: the friction coefficient, the linear wear rate of the brush and collector paired with a brush made of a given material, and the transient voltage drop. The desirability function is a universal dimensionless criterion that does not depend on the dimensions of the quantities included in it. According to the highest value of the desirability function, a sample with an optimal set of operational properties was selected. The best combination of operational characteristics is possessed by a material with a composition of 40 % – copper; 20 % – graphite; 40 % – molybdenum disulfide.
Keywords: collector, friction, wear, electrical resistance, high temperatures, materials, desirability function.
CALCULATION OF OPTIMAL DIMENSIONS
OF CONTACTLESS MAGNETIC MECHANISM
OF TRANSLATIONAL MOVEMENT
Authors: A.N. BOLOTOV, Dr Sc.,
V.V. NOVIKOV, Cand. Sc.,
O.O. NOVIKOVA, Cand. Sc.
Abstract: The article develops the design of the mechanism taking into account the requirements for operation in conditions of extreme pressures, temperatures, lack of energy consumption and maintenance. The magnetic system is a composition of permanent magnets with alternating polarity made of rare earth metal alloys with cobalt SmCo5. Based on the fact that the magnetization of magnets made of rare earth metal alloys can be assumed to be homogeneous, anisotropic and independent of the magnitude of the demagnetizing field, the Ampere hypothesis was adopted to calculate the magnetostatic forces of the mechanism. The theoretical calculation of the tangential force of the interaction of magnets made it possible to calculate the optimal dimensions of the magnetic system and obtain the greatest pulling force with the minimum overall dimensions of the mechanism. Experimental analysis of the simulation results of tangential magnetostatic forces of the mechanism with magnets made of SmCo5 alloy showed that the discrepancy between the calculated and experimental values of the force did not exceed 12 %.
Keywords: contactless magnetic mechanism, magnetostatic interaction, magnetic force characteristics, permanent magnets, magnetic system
NORMAL AND TANGENTIAL STIFFNESS OF A FLAT JOINT OF FRACTAL SURFACES
Authors: M.A. IZMEROV, Cand. Sc.,
V.P. TIKHOMIROV, Dr Sc.
Abstract: In paper a fractal roughness description model and a contact interaction model for engineering surfaces are proposed. The results describing the normal and tangential stiffness of a flat joint are obtained. A comparison with the literature experimental data of other studies is made.
Keywords: roughness, roughness parameters, stiffness, geometric modeling, mathematical models.
MAGNETIC NANODISPERSIVE LUBRICANT OILS STABILIZED WITH POLYMERS
Authors: A.N. BOLOTOV, Dr. Sc.,
G.B. BURDO, Dr. Sc.
Abstract: The technology of synthesis of magnetic lubricating oils based on carboxylic acid diesters is considered. A distinctive feature of the synthesis process is the creation of protective polymer shells on dispersed particles by means of monomer polycondensation to increase the colloidal stability of nano oils under boundary friction conditions. The experimental data presented convincingly show that the lubricating properties of magnetic oils can be significantly improved by introducing additives and fillers into their composition. In some friction modes, magnetic oils show even higher tribo-properties than traditional non-magnetic oils. The created magnetic nano oil with high anti-friction and anti-wear properties can be used to lubricate magnetic bearings, magnetic-liquid mechanical seals, gears with a magnetic lubrication system, etc.
Keywords: magnetic nano oil, friction, wear, magnetic colloid, polymer shells, viscosity, lubrication.
ON WEAR CHARACTERISTICS OF STEEL SURFACES HARDENED BY LASER RADIATION
Authors: V.V. IZMAILOV, Dr. Sc.,
L.E. AFANASIEVA, Cand. Sc.,
M.V. NOVOSELOVA, Cand. Sc.
Abstract: The results of studies of the characteristics of abrasive wear resistance of steel specimens hardened by laser hardening in the course of continuous radiation from a multichannel CO2 laser are presented. It is shown that the gradient of mechanical properties in depth, which is the result of laser action on the material, can lead to an increase in the wear rate during friction. This circumstance has to be taken into account in the experimental determination of the wear resistance characteristics of materials in rubbing pairs. It is shown that the well-known Holm – Archard wear equation is also applicable in the case of wear of parts with a hardness gradient in depth. A formula is obtained for calculating the wear coefficient in such conditions. Based on the obtained theoretical dependences, the wear resistance characteristics of specimens made of two grades of steel (R6M5 and 30KhGSA) after laser surface hardening were experimentally determined: the wear coefficient and the specific energy of destruction of the material during wear. It is shown that laser action reduces the coefficient of friction and increases the wear resistance of specimen surfaces made of high-speed steel by 20…30 %.
Keywords: laser hardening; constructional steel; high speed steel, abrasive wear resistance, wear coefficient
DETERMINATION OF RATIONAL PARAMETERS OF GUTTER-SHAPED SORTING CONSISTING OF SHAFTS WITH MOVABLE APRONS
Authors: A.V. KONDRATYEV, Dr. Sc.,
S.M. KOCHKANYAN, Cand. Sc.,
T.I. LYSENKO, senior lecturer
Abstract: The results of studies of the influence of structural, kinematic and technological parameters on the efficiency and time of the gravel screening process on the gutter-shaped sorting consisting of shafts with movable aprons are presented. The dependences of the efficiency and time of the gravel sifting process on the angles of inclination of the gutter-shaped surface of the sieve, the rotation frequency of shafts with disks, the speed of movement of aprons and the step of their placement are obtained. Multifactorial planning of the experiment was carried out and rational parameters of the gutter-shaped sorting consisting of shafts were determined, ensuring high efficiency of the screening process of stone materials.
Keywords: gutter-shaped sorting consisting of shafts, factors, movable aprons, longitudinal and transverse angles of inclination of the sieve, frequency of rotation of shafts with disks, apron movement speed, filing of the material, screening efficiency and time, gravel
SUBSTANTIATION OF THE LINING PLATES MATERIAL FOR BELT CONVEYORS DRIVE DRUMS
Authors: E.Yu. ZIBOROVА1, engineer,
V.U. MNATSAKANYAN2, Dr. Sc.,
A.A. KOMISSAROV2, Cand. Sc.,
S.V. SEVAGIN2, postgraduate, D.O. SOLODOV2, student
Abstract: The article is devoted to the issues of increasing the durability of the rubber ceramic lining of the drive drums of heavily loaded conveyor belts based on the rational choice of material for ceramic inserts of the lining cloth. The analysis of the nature of the interaction of ceramic plates with the conveyor belt, as well as the study of stresses caused in the plate under the action of operational loads, allowed us to identify a set of requirements for the mechanical properties of aluminum-oxide ceramics that ensure reliable operation of the drive and efficient operation of the conveyor. The article proposes grades of alumina ceramics, presents the main technological stages and conditions for the manufacture of plates that contribute to obtaining the required mechanical characteristics and porosity of ceramics, and also presents the results of bending and crack resistance tests of samples from the proposed grades of materials.
Keywords: belt conveyor, drive drum, rubber ceramic lining, aluminum oxide ceramics, production technology, structure, properties, porosity
ANALYTICAL MODELING OF THE INTERACTION OF PERMANENT MAGNETS MADE OF SUPERCRITICAL MATERIALS
Authors: A.N. BOLOTOV, Dr. Sc.,
G.B. BURDO, Dr. Sc.
Abstract: The purposeful design of systems with magnetic-passive bearings is complicated by the lack of theoretical methods for calculating optimal magnetic systems that take into account the physical characteristics of the properties of high-coercive magnets. The paper solves the problem of calculating the force of magnetostatic interaction between two permanent cylindrical and annular magnets. The materials of magnets of the P-Co type, Fe-B, which have a demagnetization curve close to a rectangular one and sufficiently high values of coercive force, are considered. The Ampere hypothesis is used, according to which permanent magnets are represented in the form of solenoids equivalent to them. Ring magnets are equivalent to a system of two coaxial solenoids having the opposite direction of current in the windings. Analytical expressions for calculating the normal and tangential interaction forces of permanent magnets are obtained. The model can be used to determine the similarity criteria of magnetic bearing systems, calculate the optimal dimensions of permanent magnets, load capacity and stiffness of magnetic bearings.
Keywords: magnetic field, design, magnetic-passive bearings, magnetostatic interaction
OPTIMIZATION OF THE PRODUCTION SYSTEM STRUCTURE IN A MULTI-NOMENCLATURE MACHINE-BUILDING PRODUCTION
Authors: E.V. POLETAEVA, Cand. Sc.,
I.V. GORLOV, Dr. Sc.
Abstract: In the conditions of small-scale machine-building production, the frequent change in the nomenclature of manufactured products dictates the need to accelerate technological design and improve its quality by optimizing engineering solutions using computer-aided design tools. The article deals with one of the important tasks of optimizing the structure of a production system, the basis of which is a machine tool system. Models describing the production system at different stages of design are presented. An optimization algorithm allowing to combine several models into one system which can be used for modern progressive technologies is developed. An example of model building when optimizing the structure of production machine tool system for machining of case parts at the group organization of machine building production is given.
Keywords: design automation, technological preparation of production, multi-nomenclature production, modeling, optimization, structure of production system
INTELLIGENT DECISION SUPPORT IN THE DIAGNOSIS OF ENT DISEASES
Authors: G.B. BURDO1, Dr. Sc.,
E.G. PORTENKO2, Dr. Sc.,
N.A. VASHNEVSKAYA2, Cand. Sc.
Abstract: The article discusses one of the approaches to the creation of intelligent expert decision support systems for the diagnosis of chronic pharyngeal diseases. design systems by technological processes of mechanical processing. The approach is based on generalizing the experience of diagnosing diseases. Groups of parameters taken into account in the diagnosis of ENT diseases of this type were identified. Each group of parameters, as well as each of them, were assigned weights by experts, allowing them to assess the expectation of confirmation of the expected forecast. Based on these data, by developing production models of knowledge and implementing the fuzzy sets methodology, algorithms were developed to assess the degree of confidence in the correctness of the diagnosis.
Keywords: decision support, fuzzy sets, artificial intelligence, production models, diagnostics, ENT diseases
DESIGN OF PEAT MACHINES (TO THE 100 ANNIVERSARIES OF TSTU AND THE DEPARTMENT OF TECHNOLOGICAL MACHINES AND EQUIPMENT)
Authors: L.V. KOPENKINA, Cand. Sc.
Abstract: The article discusses the design process of peat machines, which is necessary for the modernization or creation of new equipment at the present stage and in the future of its development, which is the main and defining direction in the training and research of the Department of Technological Machines and Equipment (TMO) of the Tver State Technical University, celebrating 100 years since their foundation. The use of applied computer programs with the generalization and use of accumulated experimental data in the design of peat machines in the educational process for the formation of a competitive specialist is described. The advantages of using applied computer programs for solving problems of calculating and designing peat machines, in particular for surface profiling.
Keywords: peat, peat deposit, machine, design, profiling, correlation function, applied computer program