Vol 14, No 3 (2014)

Full Issue

AIRCRAFT AND SPACE ROCKET ENGINEERING
Models of reliability and determination of acceptable periodicity of maintenance of ageing aircraft fleet
Pisarenko V.N.
Abstract

Mathematical models of aircraft maintenance are discussed in the paper. The first model is that of aircraft downtime, which is a function of the number of periodically performed technical operations. The second model is that of optimal maintenance periodicity to support airworthiness in conditions of providing a given level of aircraft reliability. The third model is an optimization model of aircraft maintenance costs and providing maximum profit in market economy conditions. Using the theory of differential equations as well as the theories of reliability and renewal formulae of calculating optimal allotted aircraft downtime during periodic technical operations aimed at supporting the airworthiness as well as the formulae of optimal maintenance periodicity, optimal number of maintenance operations and getting maximum profits from flight operations have been found. The proposed models are investigated with a view to specifying acceptable maintenance periodicity with regard for the cost-benefit ratio of aircraft maintenance and the possibility of using them to optimize the maintenance of the ageing fleet of civil aviation. The calculations made show the necessity of decreasing maintenance periodicity in order to optimize the servicing and efficient use of the aircraft ageing fleet.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):7-15
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Stochastic method of investigating perturbed motion of a space vehicle in the atmosphere
Sokolov N.L.
Abstract

When space vehicles (SVs) are moving in the atmosphere detailed accounting of the influence of external perturbation factors is quite difficult: they are either unknown or have a complex nature. This necessitates development of methods to solve the problems of controlling SVs in conditions of uncertainty. A stochastic method of investigating perturbed paths of space vehicles in the atmosphere has been elaborated. The method is based on the mathematical theory of continuous Markovian processes. The principle of reduction from deterministic description of space vehicle motion to the stochastic one is applied. A SV is supposed to be in a limited number of states that are determined by a previously chosen algorithm of phase space discretization. Differential Kolmogorov equations for determining the probabilities of a SV being in each of the states and relationships for the calculation of mathematical expectations of SV space phases are set up. Relationships for calculating the rates of SV transition from one state to another are developed and validated. Ways of reducing the duration of the processes of calculating SV flight paths are proposed. Analytical relationships for determining the values of phase coordinates are formulated. Numerical results of calculating flight paths in a wide range of boundary conditions of SV design characteristics are given. The possibility of applying the proposed method for the analysis of SV motion in the atmosphere in conditions of conditions of flight indeterminacy is shown.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):16-24
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MECHANICAL ENGINEERING AND POWER ENGINEERING
Development of a low-emission bifuel combustion chamber
Bubentsov A.V., Vasiluk D.K., Golubev P.A., Kirichenko R.E., Tashkinov V.A., Shoshin V.B.
Abstract

The paper presents the experience gained by the “Saturn” science-and-production association in producing a bifuel combustion chamber for the E70/8RD engine. The data on the modernization of the combustion chamber based on the RQQL (rich /quick quench/poor combustion) technology that made it possible to reduce significantly the emissions of NOx while working on natural gas and to meet the requirements of the technical project of the engine are presented. The problem of providing the thermal state of the flame tube walls is also discussed.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):25-33
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Application of thermoplastic hardening for restoration of fatigue durability of gas turbine disks
Vishnyakov M.A.
Abstract

The main concern of the paper is the research of expediency of applying the method of thermoplastic hardening to restore the performance of the essential parts of gas turbine engines with expired service life. For this purpose at the first stage the known repair technologies the main objective of which was to increase the operability of parts by restoring the mechanical characteristics of their material are analyzed. It was found that the technologies applied do not make it possible to achieve the goal due to the formation of tensile residual stresses in the surface layer of the part as well as the distortion of the structure of the material the part is made of and, as a consequence, the reduction of its mechanical characteristics. The method of thermoplastic hardening makes it possible to create favorable tensile residual stresses while maintaining the initial structure of the material. The fatigue tests carried out confirmed the efficiency of applying the method of thermoplastic hardening at the final stage of technology of restoring the part’s performance. It is shown that the difference of the endurance limits of new parts and those restored according to the proposed technology of repair using the method of thermoplastic hardening is 5%.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):34-41
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Peculiarities of distribution of dynamic disturbances in composite rods
Karimbayev T.D., Mamayev S.
Abstract

The paper deals with longitudinal elastic-plastic impact on a two-layer composite rod with a fixed opposite end. The composite   rod consists of a soft layer (aluminum) and a hard layer (steel), with their position varying. The condition of the continuity of the particle velocity vector and the stress is met on the contact boundary of the rods. To describe the wave processes the grid-characteristic method is used which makes it possible to construct computational algorithms on the borders of the integration area and the interfaces correctly. The interaction of reflected and refracted stress waves at the interface of composite rods is analyzed.. The phenomena on the interface of composite rods are made more complicated by their interaction with the dynamics of changing both the applied external load and the stress waves reflected from the boundary surfaces. As a result of numerical studies we have shown the possibility of damages on the interface for an aluminum-steel composite rod and rapid decay of non-linear effects in the case of steel-aluminum. Positioning rods with specific mechanical characteristics in the order specified by the calculations, we found a possibility to control the level of dynamic loading of each individual element of the composite rod, and hence the operability of the whole composite rod.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):42-52
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Calculating sound insulation of a sandwich structure on the basis of the «inverse matrix» method
Popov P.A., Osipov A.S., Sindyukov A.A.
Abstract

Multilayered structures are widely used in housing construction, shipbuilding, aviation and space-rocket engineering. In designing such structures it is necessary to estimate their sound insulation capacity for the forecasting of levels of noise taking place in this or that premise or compartment. The paper presents a methodology of calculating sound insulation of a multilayered structure  developed on the basis of solving wave equations in each of the layers taking into account the incident angle of sound waves and losses in layers; introduction of boundary conditions establishing equality on the borders of media of normal  oscillatory speeds and acoustic pressure; drawing up a system of  algebraic complex equations and a matrix equation corresponding to them; drawing up  an inverse matrix of factors at functions of acoustic pressure. Examples of calculating factors of sound insulation for multilayered structures with various parameters are presented (superficial weights, thickness of layers, various incident angles). A graphic comparison of the results of calculations using the methods of “inverse matrix” and the impedance method as well as a graphic comparison of results of flight-design measurements (FDM) of the sound insulation of a regular head part, consisting of layers of coal tape, fiber glass fabrics, aluminum honeycombs and a layer of polyurethane foam are given. The results of calculation using the “inverse matrix” method are given and the advantage of the method is emphasized.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):53-60
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Deposition of aluminum coating on items made of high-strength steel by chemical vapor deposition of an organometallic compound with the use of a catalytical additive
Pugin A.V., Gafurov I.I.
Abstract

The paper presents the results of work involving chemical vapor plating of an organometalic compound of aluminum coatings on a high-strength steel backplate using a catalytical additive. The process of coating deposition is carried out in a sealed chamber with subsequent capture of decomposition products in a nitrogen trap, which provides environmental safety of the process. The paper describes the choice of a catalytical additive among the following liquids: titanium sec-butoxide, titanium tetrachloride, three-n-propylamine used to reduce the deposition temperature. It was found that the deposition of pyrolysis-induced aluminum coatings using catalytical additives does not change the mechanical properties of high-strength steel. Corrosion tests have shown that the protective properties of samples with pyrolysis-induced aluminum coatings are superior to those of zinc coatings.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):61-69
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Specific electrical conductivity of chromium plating and nickel plating electrolytes
Salakhova R.K., Semenychev V.V., Tihoobrazov A.B.
Abstract

The paper presents the results of measuring specific electrical conductivity (SEC) of chromium and nickel plating electrolytes with the help of a non-contacting conductivity meter of the CRAB-d 064 type in temperature intervals corresponding to the working ranges of electrochemical deposition processes. A schematic diagram of the apparatus for the measurement of electrolyte SEC is presented. Electrolytes based on chromium compounds of varying degrees of valence (Cr3+ Cr6 +) and a standard nickel electrolyte (Watts electrolyte) were chosen as the objects of study. The dependence of the SEC of electrolytes on their temperature is analyzed, a comparative assessment of the impact of temperature on the electrical conductivity of various chroming electrolytes is given.

The influence of addition of nanoparticles of aluminum oxide and silicon carbide with the dispersion of 40-100 nm and a specific surface area of 23-32 m2 / g on the amount of electrical conductivity of an oxalate-sulfate electrolyte for chromium plating at a specified temperature is investigated. The study of nanosuspensions showed that the addition of nanoparticles of different nature with the concentration of 5-10 g / l to an electrolyte has no significant effect on the value of SEC.

To evaluate the relationship between the electrolyte conductivity and process parameters of electrodeposition of chromium and nickel coatings a qualitative assessment of chromium and nickel current output was performed and bar graphs showing the ratio of the values of the electrolyte electrical conductivity and the metal current output are presented. It has been established that the electrical conductivity of electrolytes and the metal current output are parameters that do not depend on each other.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):70-78
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The nature of «black spots» formation on the surface of large parts made of aluminum alloys in the process of anodic oxidising
Semenychev V.V., Salakhova R.K.
Abstract

The causes of black spot defects detected on the surface of large parts made of aluminum alloys (D16chT, 1973T2, V95pchT2, V95pchT3) following anodic oxidation   are investigated in the paper. A hypothesis of such defects appearing during the dissolution of intermetallics on the surface of a part in the process of etching during anodizing was put forward and tested. A technique was developed for this purpose the essence of which was that an intermetallic was detected on a polished sample and using a microhardness tester the area including the intermetallic was marked to facilitate its subsequent detection at the end of the specimen etching. After the etching of the specimen during periods of different duration in an alkaline bath of the anodizing line the area containing an intermetallic previously labeled using the microhardness tester was detected by microscopic observations and photographed. The duration of the etching process was 120 seconds and consisted of 8 cycles. Metallographic tests of the specimens. revealed the fact that in the process of etching of an aluminum alloy dissolution (etching) of intermetallic particles opening out on the surface of the part takes place. Subsequent anodic oxidation leads to the visualization of defects which have the form of black spots.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):79-84
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Research of a heat-resistant intermetallic underlayer for the heat-shielding coating of gas turbine engine turbine blades
Tarasenko Y.P., Tsareva I.N., Berdnik O.B., Fel Y.A., Krivina L.A.
Abstract

The paper presents the results of research of the structure as well as physical and mechanical properties of a heat-resistant intermetallic coating of a “Ni-Co-Cr-Al-Y” system produced by the method of high-energy plasma powder spraying and used as a substrate in forming a heat-shielding zirconium dioxide coating. A coating is produced with an intermetallic phase composition (b-NiAl+ g’-Ni3Al) and spheroidal grain microstructure. The density of the coating is r=8200 kg/m 3, the microhardness is Нm=7,85 GPa and the roughness is 5mkm. According to the results of testing the heat shielding of the wall of a turbine blade made of the ЖС6Ф alloy with the help of a heat-shielding ZrO2 coating with a “Ni-Co-CR-Al-Y” substrate the metal temperature reduction amounted to 398 K. The coating is intended for the protection of the working surface of various-application gas turbine engine turbine blades against high-temperature gas corrosion in the form of a substrate for the heat-shielding zirconium dioxide coating, and also as an independent heat-shielding coating. The plasma heat-shielding coating for the “Ni-Co-CR-Al-Y” system has been tested as a substrate for a heat-shielding coating of zirconium dioxide with a view to extending the service life of turbine blades (made of a heat-resistant ЖС6Ф alloy) of the NK series gas turbine engine turbines.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):85-94
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Universal approach to the description of working medium chambers for simulating hydraulic and pneumatic systems
Timofeyev Y.M., Khalatov E.M.
Abstract

The article is concerned with the consideration of methods of mathematical formulation of processes in interthrottle chambers and working medium reservoirs used to simulate the operation of hydraulic and pneumatic systems.

Consideration has been given to a general approach to the development of mathematical models of hydraulic and pneumatic systems; the stages of constructing models are also presented.

A generalized mathematical model of a heat-insulated chamber with variable volume is presented. The derivation of standard mathematical modules of the above chamber on the basis of the generalized model is given. The assumptions taken into consideration with the existing methods of describing the processes taking place in chambers and reservoirs of hydraulic and pneumatic systems are analyzed. The shortcomings of the existing methods are shown.

An approach to forming a mathematical formulation is proposed, which is universal in its nature and reflects the processes under consideration in full measure. The proposed description method is based on the laws of conservation of thermodynamics of a variable-mass body. A special record of thermal and caloric equations of the state model makes it universal and independent of the working medium type. When compiling the digital models of chambers, both equations of working medium state and tabulated reference data can be used.

 Design diagrams and mathematical models of heat-insulated chambers with variable and constant volumes are presented as an example. A digital model is presented and the results of modeling the operation of hydraulic and pneumatic actuators performed with the use of the proposed method are given. The digital model is implemented in the training version of the Russian software package “Simulation in technical devices”.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):95-108
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Research of the dynamics of condensed product deposition
Tsaplin S.V., Bolychev S.A.
Abstract

The paper is devoted to the research of structural nonmetallic materials used in the construction of spacecraft for mass loss and gas release in a vacuum-thermal environment, as well as the research of the dynamics of deposition of gas release condensed products on the optical surfaces of optical equipment. A test bench has been developed for carrying out research of the dynamics of deposition of condensed products based on quartz crystal microbalance. In accordance with the State Standards GOST R 50109-92 mass loss and gas release tests of structural non-metallic materials (fiberglass, fiberglass honeycomb panel, polyurethane foam, tapes, textiles, adhesives, etc.) used in spacecraft construction have been carried out. The effect of the deposition of condensed products of gas release from these materials on the transmission coefficient of the optical element is determined. A conclusion about the possibility of using these materials in constructing spacecraft is made.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):109-121
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ELECTRONICS, MEASURING EQUIPMENT, RADIO ENGINEERING AND COMMUNICATION
Nonparaxial iterative calculation of diffractive optical elements focusing in a subwave light spot
Bogdanova E.Y., Khonina S.N.
Abstract

The main efforts in overcoming the diffraction limit have been recently concentrated on the use of damped waves. The implementation, however, is connected with a serious drawback: superresolution is attained only in the immediate vicinity of the device, namely, at a distance of less than the wavelength. It is, therefore, impossible to use the available results, in particular, to reduce information on optical media. The aim of the paper is calculation of optical elements for subwave focusing of a monochromatic wave at a distance of several dozens of wave lengths. The problem of overcoming the diffraction limit expressed in accordance with the Abby theory and the Raleigh criterion dealt with in multiple fundamental and applied investigations is discussed in the paper. The analysis of subwavelength localization of radiation based on the interference effect that makes it possible to reduce the sizes of a light spot due to redistribution of energy in the peripheral area holds a prominent place in the paper. Calculations are performed using the iterative algorithm based on the method of plane wave expansion and the method of main directions. The problem is considered for the cylindrical and radial cases. Special attention is given to the search of solutions that would be more convenient for practical implementation. Prospective viability of developing the solution of the problem for data storage, contactless probing and nanolithography is demonstrated.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):122-129
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Crystal lattice identification on the basis of assessing unit cell parameters
Kirsh D.V.
Abstract

The paper is devoted to the problem of crystal lattice identification in three- dimensional space. Two identification methods based on assessing the parameters of unit cells have been developed to solve this problem. The first method is based on the calculation and comparison of the six basic cell parameters: the three lengths of the cell sides and the three magnitudes of angles between the sides. The second method is based on the calculation and comparison of Wigner-Seitz cell volumes using the Monte-Carlo method. Both methods include normalized similarity measures for the parameters calculated: the edge similarity and the angle similarity measure for Bravais unit cells and the volume similarity measure for Wigner-Seitz cells. A number of computational experiments for crystal lattice identification were carried out using these methods. In the course of the experiments, first, the dependence of the accuracy of defining the volume of a Wigner-Seitz cell on the number of the points included and, second, the probability of accurate Bravais lattice identification when comparing different sets of the parameters assessed have been specified. As a result of the experiments carried out, the accuracy of identification for four systems of Bravais lattices exceeded 95 per cent.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):130-137
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Simulation of ultrashort pulse transmission in a chain of fused silica microspheres
Kozlova E.S.
Abstract

The paper is devoted to the simulation of ultrashort pulse propagation in waveguides of two types. The first type (type 1) represents an ordinary waveguide made of cylindrically shaped fused silica without coating. The second type (type 2) consists of microspheres made of the same fused silica following one another. A three-parameter Sellmeyer model is used to take into account the dependence of electrical permittivity on the frequency of radiation. The coefficients of pulse broadening and amplification as well as the coefficient of the pulse spectrum narrowing have been calculated. The numerical simulation using the FDTD method which takes into account the frequency dependence of the permittivity and implemented in the FullWAVE software package  showed that there is no temporal broadening in the case of  propagation of linearly polarized ultrashort pulse  3.55 fs long with a central wavelength of 532 nm in a waveguide consisting of a sequence of fused silica microspheres with the radius of 1 mkm, while there is a two-fold temporal broadening of the  pulse  in the case of transmission of this pulse in a conventional silica cylindrical waveguide.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):138-143
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CONTROL, COMPUTER SCIENCE AND INFORMATION SCIENCE
Ontology description languages for high-tech fields of applied engineering
Burakova E.E., Borgest N.M., Korovin M.D.
Abstract

The main task of ontology description languages is to describe semantics of domain data. Nowadays, ontology is the most common form of representation of semantically-interconnected data. Ontology consists of a set of concepts in a domain and relations between them. In this paper we consider the problems of existing toolkits for creating semantically-interconnected data storages for engineering domains and propose a solution in the form of an ontology. A modern approach to the classification of assets for ontology engineering is presented. The strengths and weaknesses of the approaches described are highlighted. The paper describes problems of structuring data in the engineering domain and the ways they can be solved using ontologies. A brief review of the common ontology description languages is given. Examples of the applied ontological approach in the database creation in the airspace engineering domain are presented. XML and HTML are highlighted as the most widespread languages in the description of subject areas in modern information systems. The OWL ontology description language is described in detail as the most promising ontology description language recommended by the W3C. Varieties of the OWL language are described in terms of their applicability to solving various problems of describing engineering domains taking into account the limitations of descriptive ability and complexity of the syntax of each version. Examples of the use of the OWL language in engineering domains are given.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):144-158
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Method of compression of digital halftone images on the basis of markov chains with several states
Petrov E.P., Harina N.L., Rzhanikova E.D.
Abstract

The paper presents a mathematical model (MM) of a digital halftone image (DHI) on the basis of a two-dimensional Markov chain with several states; its adequacy to real images is analyzed. On the basis of MM a method of DHI compression is developed. The method provides separation of DHI into binary images with subsequent combining of two digits in a plane. Each plane is considered as a two-dimensional random Markov process with several (N=4) states. On the basis of the theory of random Markov processes prediction of the plane elements is carried out. All incorrectly predicted elements are located in a bit stream and serve as a reference for the recovery of the image. Separation of areas containing background noise with a structure similar to the white gaussian noise (WGN) is carried out beforehand for the planes containing low- order bits, these areas are not stored, they are filled with WGN samples in case of restoration. The efficiencyof the method is no inferior to that of known methods of compression based on DCT or DWT, it does not involve computing operations and makes it possible to work with multidigital images (8 and more digits) without increase in the time of compression due to parallel processing of the planes.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):159-167
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ECONOMICS AND HUMANITIES
Semantic status of the concepts «innovation», «innovation process», «innovative product» (methodological aspect)
Sosnina T.N.
Abstract

The paper deals with the semantic roots of such concepts as «innovation», «innovation process», «innovative product»; reasons are given for the necessity of looking for criteria of distinguishing innovations from pseudoinnovations. The author’s version of defining the above-mentioned concepts from the perspective of the theory of the subject of labour is presented. The «innovation» concept can be used in cases when consumer-cost and cost process chains are designed with regard for technical and technological, economic, social and ecological components both at the level of tactical aims (obtaining a product with a parameter required by the society) and at the level of strategic aims (obtaining a product the production of which causes minimum damage to the biosphere). The «innovation process» concept can be used referring to life cycles in which, starting from the product of nature (the object of research), through intermediate stages at which the technological waste is utilized to the product of nature when the final industrial and household products out of use are added to the biogeochemical Earth cycles. The «innovative product» concept can be used to denote the final products of material production that find practical application in the achievement of the required technical and technological, economic, social and ecological effects and taking measures to utilize the by-products during the life cycle and at the final stage through the connection of the ballast substrate to the biogeochemical Earth cycles.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2015;14(3):168-180
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