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FRETTING WEAR: REGIMES AND KEY FACTORS
Authors: V.V. IZMAILOV, M.V. NOVOSELOVA,
Abstract: Using a model of an electrical contact connection, the influence of the key factors on the fretting wear process was experimentally studied. They are as follows: the material of the contacting parts, the normal contact load and the magnitude of tangential microdisplacements. The mechanism of this influence is revealed using the so-called map of fretting wear regimes. An example of such a map for the studied contact pairs is given. On the map of wear regimes, two main areas are distinguished – the area of partial slip and the area of gross slip in contact. All experimentally studied contact pairs fall into the gross slip area, in which the main fretting wear mechanisms are adhesive and abrasive. An indicator of the condition of a worn connection is the value of contact electrical resistance, which is very sensitive to the properties of the surfaces of the contacting parts. The criterion for achieving the limiting state of an electrical contact connection was a sharp increase in contact resistance. It is shown that the optimal choice of material for the contacting parts, normal load and tangential rigidity of the contact connection can significantly increase its service life
Keywords: fretting wear, contact electrical resistance, maps of fretting wear regimes.
PROCESSING OF TECHNICAL CERAMICS
WITH AN ABRASIVE DIAMOND TOOL
Authors: A.N. BOLOTOV, V.V. NOVIKOV, O.O. NOVIKOVA
Abstract: The work investigated the tribological characteristics of a tool made of a composite material, which is a ceramic matrix of aluminum oxide, strengthened with microdispersed diamond grains. Based on the classical approach to the deformation of rough surfaces, a model has been constructed that allows us to evaluate the influence of the structural components of a tool made of diamond mineral-ceramic material on the wear of technical ceramics. Relationships have been obtained for calculating grinding productivity, the diamond content in the worn layer of an abrasive tool, and the specific consumption of diamonds. The experimental studies carried out confirmed the theoretical conclusions. It has been established that the diamond grain size and load-speed conditions have the greatest influence on grinding performance. It is noted that the concentration of diamonds significantly determines the relative wear resistance of abrasive tools. The obtained relationships will be useful in the design of diamond-containing tools for processing technical ceramics.
Keywords: abrasive diamond tools, diamond mineral ceramics, ceramic processing, contact interaction model, grinding performance, wear of diamond tools.
INFLUENCE OF TECHNOLOGICAL PARAMETERS OF LASER CUTTING ON THE SIZE OF THE LASER IMPACT ZONE
Authors: D.A. BARCHUKOV, I.A. SMOLYAKOVA,
L.E. AFANASIEVA
Abstract: It is noted in the article that based on the use of methods of research of thermal processes during welding, the laser impact zone formed during laser cutting of high-speed steel has been analyzed. It was shown that the size of the hardened layer is greatly affected by the laser cutting speed. On the contrary, changing the laser radiation power does not lead to a significant change in the size of the laser impact zone. The results of the work performed can be useful in developing new methods for manufacturing and hardening tools from high-speed steel.
Keywords: high-speed steel, laser cutting, technological parameters, laser impact zone.
SHAPE OF SECTIONS OF SOUD PEAT AND ITS FLEXURAL STRENGTH
Authors: А.L. YABLONEV
Abstract: The article states that the Tver State Technical University has developed, patented and created the design of a mechanical stand equipped with a digital strain gauging system capable of developing and fixing the breaking load for strength testing of samples of molded peat products. It is noted that its systematic use in order to adjust and rationalize the modes of operation of machines for extraction and production of lump peat will promptly achieve a stable quality of peat, but the methodology of application of this stand was formed earlier only for samples of lumps of round and rectangular cross-section. The information, developed materials and methodology allowing to use the created stand for all main forms of lump peat cross-sections obtained both in the field and in factory (stationary) conditions are given.
Keywords: sod peat, bending strength, cross-sectional shape of the piece, bending moment, sectional moment of resistance, moment of inertia, breaking load.
WAYS TO IMPROVE THE TECHNICAL AND ECONOMIC CHARACTERISTICS OF PRODUCTION OF LUMP PEAT
Authors: O.V. PUKHOVA, K.L. SHAKHMATOV, K.Yu. ZHENIKHOV
Abstract: The article considers the issues of reducing energy capital costs in the field production of lump peat. It is noted that the layer-by-layer slit method based on the method of mechanized extrusion molded cylindrical lumps directly at the technological sites of extraction with subsequent drying and harvesting operations. In the process of lumps production by milling-forming method it was found that the extraction is a very energy-consuming technology, so the question of reducing the costs of its production appeared. It is indicated that during milling molding, substantial loads act on the knives of the working body of the milling unit during extrusion and cause their deformation and then destruction, as a result of which the power consumption for molding increases, and thus the productivity and reliability of the unit are reduced. Specific work and required power for milling and molding are calculated, as well as the minimum tractor power required to perform the operation of milling and molding is determined. It is stated that in order to improve the technical and economic characteristics of the lump peat peat extraction site, the complex evaluation indicator was used, which allowed to select low-power equipment, thereby reducing operating and capital costs and increasing the profitability and reliability of production.
Keywords: lumpy peat, peat deposit, extraction, energy consumption, milling, profitability.
PROSPECTIVE DEVELOPMENTS FOR ROAD CONSTRUCTION
Authors: Yu.N. PAVLOV,, A.V. KONDRATYEV, S.M. KOCHKANYAN, D.G. MASLENNIKOV
Abstract: The paper presents an overview of research and development work carried out at the Department of Construction, Road Machinery and Equipment of Tver State Technical University for the mechanization of road construction. The developments that remain promising and for which research is still in progress are selected. It is noted that for the majority of them the work from problem statement to creation and testing of experimental sample has been carried out, and in the course of this work new ideas for improvement of technologies and constructions have appeared. Descriptions and some results of studies or tests of equipment for road marking, cutting bushes and small trees in the highway right-of-way, patching, preparation of dry asphalt concrete mixes and vibratory compaction of soils are given.
Keywords: road markings, right-of-way of highways, cutting of bushes and small trees, dry asphalt concrete mix, pit (pothole) repair, vibration exciter, soil compacting machine.
IMPROVING THE CORROSION RESISTANCE
OF MINING MACHINES METAL STRUCTURES
Authors: V. U. MNATSAKANYAN, X.H. NGUYEN, V.N. NGO
Abstract: The results of experimental studies of the corrosion resistance of steel samples coated with anticorrosive compounds in a 3.4 % sodium chloride solution are presented. It has been found that metal-ceramic coatings based on Zn + Al2O3 and Al + Zn + Al2O3 composites formed by cold gas-dynamic spraying significantly increase the corrosion resistance in seawater of welded steel joints, as well as monolithic steel samples.
Keywords: electrochemical corrosion, welded joints, corrosion rate, seawater, cold gas dynamic spraying, protective coatings, anodic protection coefficient.
INFLUENCE OF THE TYPE OF MILLING UNIT
ON THE QUALITY INDICATORS OF PEAT FOR SOIL PRODUCTION
Authors: K.L. SHAKHMATOV, O.V. PUKHOVA, K.Yu. ZHENIKHOV
Abstract: The article discusses the selection of a milling unit for peat extraction in order to produce soils with the lowest cost and improved quality indicators. It is noted that in order to meet the technological conditions when performing milling, there are many designs of milling devices. It is indicated that in studies directly on the fields of production with subsequent drying and harvesting operations, the MTF-14 milling cutter, PT-09 flat cutter and FPT-09 passive milling cutter were used; the milling depth was 0.02 m. It was found that after milling on the surface of the deposit, particles of different sizes fit fairly evenly into a layer, the thickness of which was predetermined by the loosening coefficient (for the PT-09 planar cutter it was 1.7 compared with 1.4 for the MTF-14 milling cutter and the FPT-09 passive milling cutter). It was found that the fractional composition of the crumbly peat depended on the natural properties of the peat deposit, as well as on the design of the milling cutter and the milling mode. At the same time, it is heterogeneous with a large number of particles with a size of more than 5 mm, which increased the quality indicators (high water retention capacity and at the same time breathability). Based on the research, it was revealed that the drying time of peat chips depended on the percentage of fractions, which was influenced by natural and technological factors (type and type of peat, degree of decomposition, moisture content of the upper layer of the deposit, type of milling unit, operating speed). It is concluded that the use of the PT-09 planar cutter for milling deposits allows to reduce production costs and obtain peat with improved quality indicators, thereby improving the economic performance of the site.
Keywords: milling, peat, peat deposit, milling unit, milling depth, peat crumbs.
ON RECURRENT AND GENERALIZED-RECURRENT SOLUTIONS OF NON-AUTONOMOUS DIFFERENTIAL EQUATIONS
Authors: S.М. DZYUBA, I.I. EMELYANOVA
Abstract: The article presents a definition of a recurrent solution to a differential equation with a periodic t right-hand side X ⃗(x,t), defined on the direct product of V×R a differentiable (of class C^2) compact manifold V located in an affine space E over the field of real numbers R, and a set R. A theorem on the existence of such solutions is also presented. As it turns out, this theorem has a number of rather important applications. Namely, for non-periodic functions t→X ⃗(x,t), a definition of a generalized recurrent solution is introduced and, based on the theorem on the existence of recurrent solutions, the existence of generalized recurrent solutions is established. It is noted that the existence theorem of generalized recurrence solutions is a direct and natural development of the well-known theorems on the existence of asymptotic almost periodic and other Poisson stable solutions of differential equations with the corresponding right-hand side X ⃗(x,t).
Keywords: smooth compact manifold, differential equations, recurrent and generalized recurrent solutions.
IMPROVING THE EFFICIENCY OF LEAN MANUFACTURING AND QUALITY MANAGEMENT TOOLS
Authors: G.B. BURDO, A.N. BOLOTOV
Abstract: The essence of the conceptual concepts of lean manufacturing and quality management is considered. The main errors in their understanding and application are analyzed. It has been established that it is advisable to implement these systems based on the study of the organization's business processes. The hierarchy of organizational and technological systems is investigated, the main tasks solved within the framework of lean production and quality management systems are shown. The tools of lean manufacturing and quality management are proposed, which are advisable to use in ensuring highly efficient machine-building production. Proposals for restructuring the structure of engineering departments of machine-building enterprises are given.
Keywords: machine-building production, quality management, lean manufacturing, business processes, system approach, hierarchy of production machine-building systems.
GENERAL RELATIONS AS A SUPPORTING STRUCTURE
OF AN AUTOMATED INFORMATION SYSTEM
OF MECHANICAL ENGINEERING
Authors: E.V. POLETAEVA, I.V. GORLOV
Abstract: The article is devoted to the issues related to the development of models of objects and processes, which are part of technological preparation of production, in the field of computer-aided design of technological processes of parts manufacturing. Conceptual objects and structural relations between these objects are considered. Special attention is paid to the terms “material object” and “generic relations”. It is shown what role they play in the knowledge system of the subject area of mechanical engineering. An example of coding of elements of machine-building production system and relations by means of structural modeling is given. The questions related to the creation of algorithms processing the coded information for solving the problems of selecting the elements of the production system at different levels of abstraction are studied. An example of engineering problem solving on the basis of the structure of terminological system of mechanical engineering ontology is given.
Keywords: mechanical engineering, design automation, technological preparation of production, ontology, structural modeling, terminological system, CALS-technologies, knowledge bases.
IMPLEMENTATION OF MODULAR PRINCIPLE
BASED ON ONTOLOGY OF SUBJECT AREA
OF MECHANICAL ENGINEERING
Authors: E.V. POLETAEVA, I.V. GORLOV
Abstract: The article notes that the introduction of the modular principle in mechanical engineering is one of the main conditions for the automation of production systems and processes. The modular representation of the processing object on the basis of the structural design of the part and technological process is considered. Within the framework of the ontology of the subject area of mechanical engineering the modules of the part are presented as conceptual objects of the terminological system. The main structural elements of the part and the relations between them, which constitute the model of the machining object, are investigated. An example of realization of the modular principle in the construction of the part of the body of rotation type is given.
Keywords: mechanical engineering, design automation, technological preparation of production, ontology, structural modeling, modular principle, knowledge bases.