2011. № 47
Mathematics. Physics. Mechanics | |
For example of fractal radar antenna it was suggested the analytical method for description of physical properties of such objects. Due to this method we can calculate difference kind physical characteristic of metallic fractal. It was shown the dependence physical properties of fractal on his dimension. Keywords: kinetic equation; fractal antenna; radar; fractal differentiation. |
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Aviation technics and technology | |
On the basis of the review of publications in domestic and foreign press the analysis of a current status of a problem of the theoretical description of the aircraft wheel shimmy phenomenon was spent. Various models such as the classical mathematical models, modern approaches to the description of oscillatory instability of rolling bodies on a hard surface by dry friction first of all are considered. On the basis of results of the analysis offers on the further perfection of the shimmy theory with reference to high-frequency vibrations of aircraft uncontrollable landing gear are formulated. Keywords: fluctuations; instability; rolling; dry friction; the chassis of the plane; shimmy шимми |
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This article is dedicated to the peculiarities of the maneuverable aircraft face design process under the cost limitation conditions. An object of analysis is a vector of technical characteristics that can be modified by the airframe cost limits. It examines mathematical models that determine the cost of the aggregate taking into account its’ technical characteristics. Keywords: design; mass; cost; airframe; parameters. |
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The article is dedicated to effect of the airframe structural/technological parameters selection on aircraft cost. Presented formula allows to compare costs of various structural/technological airframe options varied by the following parameters: Weight percentage of various material types in the construction, percentage ratio of parts and componentry manufactured by various production methods Keywords: cost, embodiment, parameters |
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The paper describes main goals and tasks which are solved by unmanned aerial vehicles. Shows the classification of modern UAVs by weight, altitude and flight duration. Analyzes the main advantages and disadvantages of using UAVs over manned aircrafts and spacecrafts. Keywords: unmanned aerial vehicles (UAVs), unmanned aircraft complex (UAC), unmanned aircraft systems (UAS), aims and objectives of the UAV. |
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The paper describes design features of new generation unmanned aerial vehicles (UAVs) as a part of unmanned aircraft systems. Elaborated approach to the development of unmanned aircraft systems (UAS), depending on the tasks assigned to the UAS. Held the analysis of possible solutions in the guise of promising UAVs types, to significantly improve aircrafts characteristics. Keywords: unmanned aerial vehicles (UAVs), unmanned aircraft complex (UAC), unmanned aircraft systems (UAS), unmanned aircraft design. |
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In this paper analyzed the situation on the world market of unmanned aerial vehicles (UAVs). Considered the main trends shaping the characteristics of the UAV based on the conditions of their application. Identified areas in which the use of UAVs is essential for ensuring the defense. Considered the possibilities of future unmanned aircraft systems. Keywords: unmanned aerial vehicles (UAVs), unmanned aircraft complex (UAC), unmanned aircraft systems (UAS), unmanned aircraft capabilities. |
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In article the question of a choice of the optimum layout decision from several offered variants in the absence of the authentic statistical data is considered. It is offered on each parameter influencing a choice of the given layout decision, to spend an expert estimation. The quantity of the parameters influencing a choice of configuration, is defined by a project stage (degree of study of a design). The coordination of opinions of experts is estimated by factor size конкордации. The purpose of increase of objectivity and trust degree to received during poll of value of weight factors the technique of definition of their sizes which considers level of competence of involved experts, on the basis of their self-appraisal and an estimation of degree of their acquaintances to field of knowledge which the estimation, corresponding heads concerns is offered. The resulted results are of great importance at designing of new products in the aviation industry at initial design stages of a product. The developed settlement module is a part of the general program on creation of the optimum layout decision of again created product. Keywords: configuration, an expert estimation, reliability of results, factor konkordacii |
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Improving the quality of products associated with improving the quality of their design, which is achieved by using modern information technologies. Considering the high density layout of a modern transport technology, is an urgent development of mathematical software and automated layout system. The basis for the creation of mathematical development and software development need the steps to geometric modeling as placed objects, and the allocating process. The report examines the issues related to the automation design - location of geometric objects among already deployed areas of prohibition. Such a problem was occured, for example, when allocating or linking the technical compartments of light aircraft. So the ability to use the results of receptor (voxel) geometric models is proposed. Placement algorithm is based on the analysis of shape and dimensions of free areas and allocating objects in suitable shapes and sizes on unplaced areas. Keywords: geometric modeling; receptor models; layout; shape recognition. |
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Space technics and technology | |
Modern applied tasks of Earth observation systems development requires to consider different factors and restrictions, including ballistic structure of system constellation, parameters of on-board special equipment as well as different requests for serving. It is necessary to provide a complex parametrical analysis of the system for choosing its optimal parameters. The special software was developed for providing such analysis. It is considered on the model example of target functioning of Earth observation system. Keywords: earth observation systems, constellations, target functioning, special on-board equipment, average observation durability, optimization, special software, modeling, parametrical analysis, estimation of the system efficiency |
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We consider the problem of transition artificial Earth satellite with an initial circular orbit to geosynchronous orbit with minimum fuel consumption. Solution in the classical setting (in the class of continuous systems) leads to an infinite sequence of impulse inclusions (at extremely the little time) of the engine with a maximum thrust of around pericenters on osculating orbits. The total fuel consumption becomes less at this mode, but the overall stabilization time increases unlimitedly. Therefore, we have considered the problem in view of inefficient fuel consumption (in the class of logic-dynamical systems). Approximate solution is based on necessary optimality conditions of logical-dynamic systems. A comparison of the conditions necessary to apply the maximum principle. The results of calculations in a classical setting, and for logic-dynamical systems, as well as their practic applicability, are discussed. Keywords: geostationary orbit, logical-dynamical systems, the necessary conditionsfor optimality. |
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In article it is stated statements of problems and results of numerical modeling of processes in Piston Gasdynamic Unit intended for reception of a supersonic stream of gas for development of products of the space-rocket mechanics. The technique of the decision of three interconnected physical problems of calculation of dynamics of movement of the piston has been developed. The algorithm of parallel calculations with use of Message Passing Interface (MPI) technology MPI for problem calculation on multiprocessing computing systems is realized. The received results of computational fluid dynamics have been comparison with results of experiment. Keywords: heat transfer, gasdynamic facility, computational fluid dynamics, Navier-Stokes equations, turbulence models, parallel calculation |
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Control systems | |
When using technical systems which can more or less threatening human life and health, especially acute question of timely maintenance of systems designed to prevent or minimize the risk of sudden failure of systems. Keywords: testing and diagnostics, aerospace systems, identification |
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Navigation systems | |
The paper discusses the on-board navigation system, which is the part of an Advanced Surface Movement Guidance and Control System (A-SMGCS), intended for use on-board of airport vehicles. The structure of the complex is offered, its basic characteristics are considered. The technique of simulation and hardware-in-the-loop modeling is given, in accordance with which the numerical investigation of system’s properties using the developed software is performed. Several scenarios of modeling are considered. One of the scenarios includes initial operation of satellite navigation system (SNS) operating in differential mode and the gap of SNS when the system continues to work in autonomous mode - by complex processing of information from the strapdown inertial navigation system (SINS) based on micro-mechanical gyroscopes and accelerometers, on-board odometer and a magnetic compass. The accuracy of navigational maintenance needed to meet the requirements of Doc 9830 AN/452 ICAO is estimated. The results are given in the form of estimation error of basic parameters and their standard deviation. Keywords: airport vehicle; Advanced Surface Movement Guidance and Control System (A-SMGCS); integrated navigation system; differential mode; on-board odometer; nonholonomy |
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Technical cybernetics. Information technology. Computer facilities | |
The article describes possible applications of effective distortion method at industry. This method increases encoding performance and protects product 3D models data. Keywords: 3D model, distributed enterprise, effective distortion method, adaptability condition, industry |
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In this paper, a mathematical algorithm for calculating the single criterion of the geometry of the Electronic Model Products (EMP). Results of the analysis methods to create a solid model in the form of local criteria affecting the complexity of the geometry of the product. The mathematical apparatus designed to automatically calculate the single criterion of the geometry of parts and assemblies. This criterion will accelerate business processes Design and technological preparation of production (ETC) machine-building enterprises of the aviation industry, due to the automatic decision-making depending on the complexity of the geometry of the EMP Keywords: the complexity of EMR; automation ETC; PLM; PDM; STEP; CALS; distribution of work; complexity of solid models; design of aerospace products |
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Material authority | |
For nitrated details of aviation technics, such as sheet details of a covering and an internal power set, details of fixture, etc. the new method low temperature nitriding – in conditions of thermo-gas cycles consisting in periodic alternation of cycles of saturation and resorption the nitrated layer is developed at the greatest possible decrease in sating ability of atmosphere. The offered new method of thermo-gas cycles nitriding is effective, new technology of hardening of modern details of the space technics allowing to 10 times to reduce the expense of sating gas and emissions in atmosphere, in 4-6,5 times - process time, and also to increase a thickness of a diffusive layer in 2-6 times without decrease in its physicomechanical characteristics. The new technological parameter – duration of the half-cycles is offered, allowing simply from the point of view of realization and effectively to regulate phase structure and a structure of a layer for the purpose of reception of demanded physicomechanical characteristics of strengthened details. Keywords: nitriding; thermo-gas cycles; duration of half-cycles; saturation; resorption (denitriding) Keywords: nitriding; thermo-gas cycles; duration of the half-cycles; saturation; denitriding; |
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Economics | |
In article some problem aspects of a current state of the enterprises of the aviation industry has been analysed, prospects of their development are defined. Ways of perfection of a technique of the scenary analysis of innovative projects of the aviation branch are considered, allowing to spend an exact estimation of level of investment risk. Classification of design risks of the innovative enterprises by level of financial losses is resulted. Keywords: innovative project, investment risk, the analysis of scenarios, net current value, business-model |
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The aviation industry is a subsystem of the Russian social production which is influenced by national and global economic systems, in relation to them it is completely open. It is characterized by long-stored state of instability and recession. Ensuring the competitiveness of the industry requires innovative transformation of production, changes in the organization and selection of system features. This should take into account the peculiarities of building knowledge-based economy and modern trends in the global market. Keywords: specific market of high-tech manufacturing, modern trends in the organization of production, innovation transformation, the global information economy, a systematic approach. |