Технологические процессы и материалы. Рубрика в журнале - Сибирский аэрокосмический журнал
Статья научная
Operational characteristics of contacting elements of cars and mechanisms are by far defined by a layer quality indicators at the surfaces of contact. One of the ways of increasing details durability, including missile and space equipment details, is the superficial plastic deformation (SPD). In the article aspects of dynamic ways of hardening from the position of the wave theory of blow are considered. The construction of a shock stand on the basis of a linear electrodynamic drive with a size of 60 mm, operating in a shock-pulse mode, as well as a well-known mathematical model of the workflow - the movement of the armature with the tool at the moment of striking the surface. This model does not fully describe the operation process since the mass of the striker taken into account equaled 1 kg, which does not characterize the process of the impact tool, the purpose of which is the object deformation (for example, work hardening with the aim of surface material sealing or breakdown of the hole in it, or applying license plates markers). The mathematical model that describes the movement of the armature with the tool, taking into account the elastic deformation of the hardened surface was obtained. In the course of the performed calculation, the magnitude of the elastic deformation of the hardened surface was calculated from the dynamic component of the force impulse applied to it through the indenter (the tip of the impact tool). The layout of the shock stand with the equipment used, are offered. Experiments on the signal recording with various arrangements of piezoelectric transducers on the anvil - the hardened surface (diagrams of the sensors location are given) were carried out.
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Mathematical model of conducting nanopore for molecular dynamics simulations
Статья научная
An electrostatic model of conducting nanopore is presented in the paper. The model does not require solution of the Poisson equation for the potential. This model is intended for use in simulation of transport phenomena of charged par- ticles in conducting nanopores by the method of molecular dynamics. This method is based on Newton’s equations of motion and it allows one to determine the variation of position, velocity and acceleration of particles with time. The electric field from the charge distributed over the nanopore surface is approximated by the field from fictitious point charges on the same surface. To verify the proposed model of fictitious charges system capacitance is calculated. The obtained values of capacitance are compared with classical results for conducting tubule and with the results obtained by the other similar method. The comparison shows that relative discrepancy between results is less than 10 %. There is a need to further develop the proposed model both in case of a large number of fictitious charges and in case when charged particles are in close proximity to the nanopore surface. The proposed method can be easily applied to an ar- bitrary shape nanopore. The model can be used in the development of various nanodevices, among them the devices used in life support systems of manned space vehicles.
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Mathematical modeling of mechanical properties of structural steels
Статья научная
On the basis of available published data and with the aid of a personal computer found equations of the dependence of the yield strength σ 0,2, of reduction of area φ and of impact toughness a 1 of a group of a structural steels on their tensile strength σ u with correlation coefficients.
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Статья научная
In this scientific work, a method of controlling high-frequency products from polymeric composite materials is con- sidered. The authors of the work present the rationale for choosing a method of high-frequency diagnostics as the most suitable for non-destructive testing of products from polymeric materials of machine-building and rocket-space pur- poses. In the presented article, the primary task of creating and studying a mathematical model of the effect of high- frequency radiation on a polymer product, including those with a “metallic inclusion” defect, has been stated and solved. In addition, the work presents the calculations of diagnostic parameters using the mathematical model devel- oped during the study. The calculation of the dynamics of heating the product and the temperature distribution during the control process is presented. The results of the calculation of specific power are described, the dependence of the instantaneous power consumption on the warm-up time is found. In the study based on a mathematical model, the Aleo- Diagnost software package was developed and registered, which is directly intended to ensure the functioning of the diagnostic devices and the investigation of the monitoring process. In addition, the developed complex allows solving a number of such practical problems as the calculation of the operating voltage depending on the geometrical parameters of the product and the determination of the value of energy consumed for monitoring the product for a specified period of time. This stage was necessary, as the consumed energy is the main output parameter of the diagnosis. In addition, the value of energy consumed is taken as the basis for the organization of the process of non-destructive testing in the automated mode. The solution of the tasks in this work has significantly reduced the cost of preparation of diagnostic operations, as well as improve the quality of control of products on an industrial scale at the stages of manufacture, operation and during repair work. The article also presents practical results, conclusions.
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Methodology of creating management programs for case presses used in the aviation industry
Статья научная
The article is devoted to the optimization of the technological process for the manufacture of aircraft parts by the tightening method on CNC presses (Computer numerical control). The aim of the work is to create a control program that provides the manufacturing of the details-sheaths of the required accuracy and quality according to the control program in an automated mode. The method of creating control programs proposed in the article takes into account the shortcomings of the S3F software, which is the apparatus for forming control programs for the equipment considered. The method is based on the choice of the optimal loading scheme, under which the deformation program is created, the values of the control coordinates of the press are calculated in accordance with the kinematic model of the press and, as a result, a control program is formed. The mathematical module for creating control programs includes several computational units using modern CAD/CAM/CAE programs. Calculations, analysis and visualization of the tightening process were carried out using software-computational complexes MathCAD, ANSYS, T-LEX, NX, etc. As a result, we obtain a control program that provides more accurate production of the part with a minimum amount of finishing work. The presented method of calculation of the tightening process makes it possible, on the basis of the details of the part, to determine the shape of the tightening punch, and also, if necessary, to adjust the existing tightening punch in order to ensure a more precise manufacturing of the part.
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Methods of preparation of the experiment for investigation of universal joints on needle bearings
Статья научная
The main directions of development and improvement of performance data of universal joints needle bearings of transport technological machines are considered. The questions and tasks requiring the solution at the level of forming of new calculation procedures are specified. Modern achievements in researches of endurance failures and low-cyclic fatigue of needle bearings are considered. The main overview of the works performed in this direction is provided. The analysis of modern ideas of fatigue processes of needle bearings is given. The analysis of the current state of question on research of plastic deformation at static contact loading of needle bearings is given. Questions of forecasting of durability of needle bearings of universal joints are considered. The main questions connected with processes of forming of fatigue cracks in materials of needle bearings of universal joints in zones of power contact are considered. On the basis of the analysis of the used sources it was revealed that it is necessary to resolve the issues connected with improvement of performance data of universal joints needle bearings and questions of calculation of bearing capacity of power contact of rolling bearings and technology of receiving qualitative materials. For carrying out tests we used the test facility for universal joints allowing tests without overheat of system of braking due to cooling of working fluid and also improving operating conditions due to ensuring smoothness of regulation of braking torque. For measurement of roughness of surfaces the USB BV-7669M Profilograph profilometer was used. For measurement of hardness of surfaces of thorns of crosspiece of universal joints the HBRV-187,5 hardness gage was used. The technique of carrying out tests includes the following stages: marking of crosspieces of universal joints; measurement of roughness, hardness, geometry of crosspieces of universal joints; stage of tests; repeated measurements of roughness, hardness and geometry of crosspieces of universal joints; cutting of the studied universal joints and production of microsections for metallographic examinatons of active and passive surfaces of thorns of crosspieces of universal joints; processing of results of researches. The given technique of planning of experiments is intended for receiving experimental data of researches of universal joints at different stages of operation that will allow to estimate influences of errors of production on performance data of universal joints and to prove the reasons of formation of face and deep cracks.
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Model-based study of oxidation processes in a jet engine fuel liquid phase
Статья научная
The process of oxidation in hexadecane liquid phase as a conventional model of oil hydrocarbons is investigated. The oxidation product structure is defined by means of Chromatography/Mass Spectrometry.
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Статья научная
Method of improvement of operational properties of surfaces is considered. Under study is the applicability of high- frequency electromagnetic field for metal heating and melting with a view to its subsequent modification. 2D numerical modeling of the processes during the modification of the substrate surface metal layer is carried out. The substrate surface is covered with a layer of specially prepared nano-size particles of refractory compounds, which are active crystallization centers after the penetration into the melt. The distribution of the electromagnetic energy in the metal is described by empirical formulas. The proposed mathematical model is used to consider the processes including heat- ing, phase transition and heat transfer in the molten metal, the nucleation and growth of the solid phase in the presence of a modifier material in the melt. Melting of the metal is considered at the Stephan’s approximation, and during solidi- fication all nano-size particles are assumed to be centers of volume-consecutive crystallization. The flow in the liquid is described by the Navier-Stokes equations in the Boussinesq approximation. The movement of the markers models the distribution of nano-size particles in the melt. According to the results of numerical experiments, the flow structure in the melt was evaluated versus the characteristics of induction heating and the amount of surface-active impurities in the metal. The modes of the induction-pulse action are detected: they promote creating the flows for the homogeneous dis- tribution of modifying particles in the melt. Found that the application of high frequency electromagnetic field for heat- ing and melting of metals allows to modify the metal deeper in comparison with the use of a laser.
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Статья научная
The development of oil deposits in the Evenki Autonomous Area is connected with study of the properties and quality index of extracted crude oil and oil fuels. The ecological requirements to oil products become more stringent today. Measures for lower oil extraction costs, oil processing and equipment exploitation are also to be met. Therefore, the study of crude oil and oil fuel properties is very important.
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Product characteristics forecasting model with support vector machines
Статья научная
Numerical models with support vector machines are used for forecasting material's properties depending on their production parameters. The paper includes practical forecasting results.
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Production of finly despersed powder from graphite by electrolysis
Статья научная
Multifunctional coating is a multi-layer structure applied to the surface of an aircraft to protect it from external influences. The main tasks of the multifunctional coating are: restoration of properties, overall dimensions, mass of the surface of the product, which were violated under operating conditions; changing the initial physical, mechanical and chemical properties of the product surface to ensure the specified operating conditions. Today multifunctional coatings based on micro glass spheres with applied tungsten are widely used in aerospace engineering. However, this coating has a number of disadvantages: the coating layers heterogeneity; the composition contains a harmful and dangerous component - a fluorone dye. In this article it is suggested to replace the main component of a multifunctional coating with finely dispersed graphite powder obtained by electrolysis. For this purpose, the equipment based on the principle of a diaphragm electrolyzer was constructed. The main elements of the device are a stainless steel cathode and a graphite anode immersed in an aqueous solution. As a result of anodic processes, a finely dispersed graphite powder was obtained. The average particle size of the resulting graphite particles is 4 microns. This finely dispersed graphite powder can be used as the main component of a multifunctional coating in aircraft, since it has an even homogeneous structure, as well as higher values of the main mechanical properties of a multifunctional coating.
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Properties of quasicrystalline Al-Cu-Fe coatings prepared by plasma spraying
Статья научная
The physical, mechanical, and tribological properties of quasicrystalline coatings based on the Al 65Cu 23Fe 12 alloy prepared by plasma spraying have been investigated. The specific features of the phase formation due to the competitive interactions of the icosahedral ψ and cubic β phases have been elucidated. Сorrelation between the microhardness and the content of the icosahedral phase in the coating has been determined. The decisive role of the quasicrystalline phase in the formation of high tribological characteristics of the coatings has been revealed and tested.
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Research of radiation and radar characteristics of a growing ice cover
Статья научная
Remote methods of monitoring terrestrial and water objects in the microwave range, both active and passive, are widely used at present. One of such objects is the ice cover, which is associated with the development of the Arctic and the Subarctic, as well as in connection with the climate change on the planet. For this reason, knowledge of the radia- tion and scattering characteristics of the ice cover in the microwave range is an urgent task. In this paper, we describe a technique for the simultaneous measurement of the radiothermal radiation and the backscattering coefficient of the growing ice cover. The technique is that measurements are made alternately of the power of the radiothermal radiation and the power of backscattering from the medium under study, and the radiation is received on the same horn antenna. Receiving of electromagnetic radiation was carried out using a microwave radiometer on two linear polarizations: horizontal and vertical. The switching time between the active and passive measurements was 10 minutes. Measure- ments of the radar and radiative characteristics of the growing fresh ice cover at a wavelength of 2.3 cm have been performed. It is shown that the active and passive radiolocation of the investigated object carries a complementary information. Radiometric measurements show interference, which is associated with a change in the thickness of the ice cover. Active radar methods record inhomogeneities comparable to the wavelength, which was confirmed in this paper, using the example of ice cover. This method of research (simultaneous measurements of the radiation and scattering properties of the medium in the microwave range) can be used at various objects where quasistatic processes are observed, for example, when measuring vegetation, drying, freezing or moistening of the soil cover, etc.
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Research the influence finishing canal shape to flow media for abrasive flow machining process
Статья научная
Visual research flow media nature as with abrasive tool put in to practice. To establish facts the influence degree finishing canal shape and form losses for flow character. The guidelines for processing environment leveling developed.
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Статья научная
This article presents an evaluation of the size, form and quantity of the particles of titanium aluminide TiAI3 in rod inoculating alloying composition, used in semi-continuous casting of ingots of aluminum and aluminum-based alloys.
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Steam turbines with a low-boiling working agent
Статья научная
The subject of the article is the assembly of a steam-generator plant with a natural working agent. A method of calculation for steam turbines with a low-boiling working agent is offered, which accounts for the correlation between the adiabatic curve indication, pressure and temperature in the overheated vapor area.
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Study of carbide formation in the plasma of a low-pressure pulsed arc discharge
Статья научная
We examine the influence of pressure and gas mixture composition on the preparation of nanomaterials via vacuum arc sputtering of titanium cathodes in carbon-containing media. The formation of carbide phases in various gaseous atmospheres is accompanied by the formation of the low-temperature phase α-Ti (hcp lattice), characteristic of pure titanium. Carbide formation in the plasma synthesis of TiC nanoparticles is determined by the C/H ratio in the molecules of the hydrocarbons used. To raise the yield of carbon-rich carbide phases and reduce the percentage of the residual metal in the resulting nanopowders, it is necessary to use hydrocarbons with a large C/H ratio, for example, benzene and acetylene.
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Study of consolidation features for fragmentally nanostructured hard metal composites
Статья научная
The results of experimental studies combined with modeling and prediction methods for the properties of hard metal composites show that modification with additives of ceramic nanoparticles and composite powders (WC-Co) allows to control microstructure parameters and provides the increase in binding durability and the level of physicomechanical properties of a hard alloy in general. Simultaneous complex application of submicrocrystalline WC carbides coated with Co layer and alloying additives of Al2O3 nanoparticles - grain growth inhibitors of the main phase, can be consid- ered as the most perspective direction of nanostructured hard metal with increased hardness, strength and crack resis- tance production. The coating of carbide particles with a binder layer is an effective starting method that allows to ob- tain a volumetric billet with maintaining the unique properties of the initial nanopowders and ensures a uniform distri- bution of the phases (WC, Co, Al2O3). Such a multiphase fragmented nanostructured composite is characterized by additional heterogeneity, determined by differences in size and elastic phases properties. By combining the sizes and properties of the phase components in such a heterogeneous composite, it is possible to provide an increase in the frac- ture energy, i. e., Palmkvist crack resistance up to 16-18 MPa m1/2 (due to inhibition on nanoparticles inclusions, stress reliefs and changes in intercrystalline crack trajectory, its length decrease). Based on the proposed stereological mod- els and the experimentally established relationships between composition and microstructure parameters, the required volume concentrations of nanoparticles additives and composite powders (WC-Co) were determined.
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Study of structural properties of bismuth pyrostannate by Raman and IR spectroscopy
Статья научная
Chromium-substituted bismuth pyrostannates with a pyrochlore structure were synthesized by the solid-phase reaction method. The X-ray structural analysis performed at room temperature showed that the samples Bi2(Sn1-xCrx)2O7, x = 0; 0.05, 0.1 are single-phase and belong to the Pc monoclinic structure. Polymorphic transformations of the synthesized samples were studied by Raman and IR spectroscopy. IR spectra were obtained at the temperature range 110-525 K and frequencies 350-1100 cm-1. Raman spectra were measured at room temperature at frequencies of 100-3000 cm-1. Heterovalent substitution of Sn4+ for Cr3+ modifies the spectra of pure Bi2Sn2O7. The crystal structure of Bi2Sn2O7 consists of two oxygen sublattices: SnO6 and Bi2O'. Chromium ions substituted tin ions in the SnO6 oxygen octahedra, distorting the local structure in the vicinity of bismuth ions. Phonon modes are softening in the vicinity of phase transitions. А shift of the phase boundaries of polymorphic transitions is observed for Bi2(Sn1-хCrх)2O7, x = 0.05, 0.1. The frequencies of stretching vibration modes were determined from IR and Raman spectra. The substitution of chromium for tin ions resulted in the appearance of two new modes at frequencies of 581 and 822 cm-1 in the Raman spectra. The absence of an inversion center in the crystal structure of Bi2(Sn1-xCrx)2O7 is confirmed by Raman spectroscopy. IR spectra of chromium-substituted samples consist of complex lines, which decompose into 2 and 3 Lorentzian lines. The softening and broadening of optical absorption modes are associated with the electronic contribution. Impurity states of electrons form polarons.
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Study of tribological properties of plasma-modified UHMWPE
Статья научная
The results of studying of nanocomposite materials based on ultra-high-molecular-weight polyethylene filled with copper oxide nanopowder produced in plasma of low-pressure arc discharge are presented. The process of the vacuum-plasma synthesis of powdered composite mixtures, which involves the treatment of powders of the polymer matrix material in a device for synthesizing nanopowders at low temperatures, is described. The results of the experimental study of the specimens are presented.
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