2011. № 44
Methods and tutorials | |
In aerospace industry one of the main issues is the problem of the qualified specialists education. During the learning process positive incentives improve the effectiveness of the education . One of such incentives is the rating system. In this work the construction and evaluation of the specialized rating system is regarded with examples on the distance learning system that is used for learning mathematical courses by students of aerospace disciplines. Keywords: aerospace education, distance learning systems, Rasch model, maximum likelihood method, recurrent algorithm, Newton’s method |
|
Mathematics. Physics. Mechanics | |
A technique for numerical simulation of viscous cavitating flow is presented. Modified PISO algorithm is implemented for the Navier-Stokes equations solution. Fluid flow through a two-dimensional variable cross-section nozzle was simulated to verify the algorithm. Keywords: саvitation, two-phase flow, PISO, Navier–Stokes equations, numerical simulation. |
|
In at work is carried out research of a laminar mode of current of nonlinear-viscous liquid the infinite slot-hole channel in view of action dissipation and chemical sources of a thermal emission at boundary conditions of the first and third sort. Bifurcation analysis of the equation of energy is made by means of a method based on decomposition of required functions in Taylor's series. Keywords: heat exchange; analytical solution; hydrodynamic equations and heat exchange; complicated rheological fluid; thermal explosion; characteristic equation; bifurcation. |
|
It is stated mathematical and numerical models of processes of carry of an electric charge near to a cylindrical probe in a cross-section stream of dense plasma at availability of an axial magnetic field. Nonlinearity in behavior of average density of an electronic current depending on parameter of the Hall is detected. In the limited interval of variation of number of Reynolds curves pass through a maximum, which which is kept at variation of dimensionless radius of a probe, its potential from the attitude of temperatures of ions and electrons. The physical explanation is given to the detected nonlinear effect. Keywords: : Processes of carry, Euler’s equation, Poisson equation, method of large paticles, magnetic field, the dense slightly ionized plasma, parameter of the Hall |
|
Aviation technics and technology | |
To improve and streamline the testing of hydraulic systems onboard aircraft analysis and evaluation of modern methods of testing as it is presented the development of modules for packaging and assembly stand steering test integrated electro-hydraulic (EGRP) complex vehicles and their systems of governance (for example control system aircraft). Keywords: Test, experimental testing, computer modeling, scaled-down modeling, hydraulic drive. |
|
This paper describes the design of a nonlinear robust-adaptive controller for an airbreathing high-speed vehicle. The control strategy, rely on Lyapunov theory, aims at stabilizing longitudinal motion. Keywords: high-speed vehicle; ramjet; longitudinal motion; flight control system; controller; Lyapunov theory; robustness; adaptivity. |
|
In the article the identification aerodynamic characteristics of the angular motion is described in the time domain from parameter’s recording of longitudinal maneuvers. The algorithm of adaptive identification is used, witch permits estimate elements of the pitching moment coefficient. As element’s initial approximation the aerodynamic database values are chosen which obtained from the results of wind tunnel tests. Keywords: Identification of aerodynamic characteristics; estimate of parameter; adaptive identification |
|
The article presents the main features of the new generation mobile tethered aerostatic complex, describes their structure and considers the design generalized algorithm. Keywords: tethered aerostat, mobile tethered aerostatic complex, design procedure, mooring system, cable rope, power supply system, automobile means, payload |
|
The present work deals with the method of the optimal choice of fuselage structure, which gives the minimum weight of the shell. The useful volume of a fuselage compartment is calculated depending on a pay load. Variants of cross-section fuselage structure are considered depending on the perception of external loading. The stress-deformed state of composite design is analyzed to estimate the maximum stress zone. The shell thickness is estimated by using conditions uniform strength. Keywords: fuselage cross-section; fuselage compartment; weight efficiency; structure thickness; structure calculation; design density |
|
The paper describes the trends of moment inertia form changing of future aircraft types on the structural diagram formation stages. Analyzed axial moments inertia values changes, depending on the production of fuel (Jx) and on the mass of payload (Jz). Done a comprehensive analysis of the moment-inertia layout parameters influence on the aircraft form. Keywords: moment of inertia; layout, structural diagram, payload, fuel. |
|
The paper describes the process of developing the algorithm, as well as the algorithm itself of aircrafts moment-inertia shape formation process automation in the early stages of design using specialized software. Developed: the moment-inertia models, algorithm, software package to determine the moment-inertia characteristics of the aircraft with sufficient accuracy, intuitive 3D interface for viewing and easy processing of computations. This work was supported by the Federal Program "Research and scientific-pedagogical personnel of innovation of Russia for 2009-2013 activity 1.2.2 on". The work has research teams under the guidance of candidates in the following areas: - design of aircraft - Microelectronics - instrumentation based on new physical principles - laser, plasma and beam technologies for nuclear technology, "state contract № 14.740.11.0340 on September 17, 2010. Keywords: moment of inertia; layout; moments of inertia, layout, software system, moment-inertia model, algorithm, automation process. |
|
The methodic of relative coordinates measuring radio system trials for estimating its accuracy characteristics and aircraft maneuverability constraints during formation flight is presented in this article. The results of these trials will be the foundation of formation flight mode development Keywords: Relative coordinates measurements; radio-technical system; formation flight mode, formation flight, flight tests, ground tests, methodology. |
|
Space technics and technology | |
The mathematical and numerical model of probe problems in the indignant zone of the companion is developed. Initial and boundary conditions for probe problems are received from predesigns of parametres of the indignant zone of the companion which is flowed round by a stream arefied plasma. Influence of the form of functions of distribution and other features of area of an arrangement of a probe on results of processing of probe experiments is investigated. It is established that the error connected with neglect by these features, can lead to processing errors зондовых experiments of 50 % and more. Keywords: The rarefied plasma, probe measurements, a cylindrical probe, the stationary plasma engine, background plasma, the Langmuir theory, Maxwell function |
|
Aerospace propulsion engineering | |
Keywords: Convective heat transfer; supersonic turbulent flows; liquid rocket jets; heat transfer coefficient; thermal protection |
|
Possibility of use of results tensometry pipeline of the plane for designing and completions of a construction of aircraft taking into account it vibrostressing is considered. Keywords: hydrosystem; tensometry; Fourier analysis |
|
Theoretical engineering. Mechanical engineering | |
The author considers an accuracy improvement method of lathing with CNC-machine, which is based on the use of the anticipatory signals obtained by means of automatic control system modeling. An anticipatory signal allows to keep constant current in the motor armature circuit at the gear load changing, which is achieved by the cutting depth regulation in the process of lathing. As a result of it elastic deflection stabilizes and lathing accuracy improves. Keywords: accuracy; anticipation; model; lathing; elasticity; depth; feed; correction; speed; force; current; armature; motor |
|
The article deals with a developed mathematical model of automatic control system in metal-cutting machine cross-feed providing higher accuracy of workpiece machining. The result is achieved by the introduction of an additional correcting signal into the gear control system, representing an error caused by the spindle eccentricity. The eccentricity error is functionally connected with cutting force and upon its change with the model help a correcting signal is formed supporting a controlled value after the transient process completion. Keywords: machine; spindle; eccentricity; machining; workpiece; model; balancing |
|
Control systems | |
The system projection methodology of pitch channel of robot pilot of flying machine with electromechanical servodrive as subsystem is considered. Projection problem is formulated as an optimization problem with the quality criteria defined in terms of the control system. The solution of the problem is based on the principles of system approach and the methods of hierarchical optimization, which make it possible to fulfill the control system decomposition and determine the appearance characteristics of there subsystems in a structure -parametric form. Keywords: system approach; decomposition; control system; subsystems; hierarchical optimization; appearance characteristics; robot pilot; electromechanical servo drive. |
|
We consider the problem of learning simple and complex skills in the formation of a training plan taking into account the individual characteristics of trainees. The possibility of automation of learning in a computer class. Keywords: Computer systems; mathematical models; individual training; parameter optimization. |
|
Instrument making | |
The solution of the problem calibrating airborne gravimeter in the process of shooting. Propose an algorithm to calibrate the gravimeter using methods of multiresolution analysis (MRA) based on wavelet-transform. Numerical results are given. Keywords: gravimetry; gravity anomaly; multiresolutional analysis; wavelet transform |
|
Radio engineering. Electronics. Telecommunication systems | |
Results of the analysis of expediency and possibilities of harmonisation of the purposes of im-provement of onboard radio telemetering systems and program and technical means of telemetering complexes of the cosmodromes in the course of their development, development of the enterprise of space-rocket branch and standardization process development of the domestic telemetry concerning the space-rocket and rocket industry are presented. The considerable attention is given scientifically-methodical aspects of standardization. Keywords: efficiency, standardization, the space-rocket and rocket industry, telemetry, onboard radio tele-metering system, program and technical means, telemetering complex of the cosmodrome. |
|
Material authority | |
Article is devoted to development of geometrical model within the framework of one of the major methods of reception of products from composite materials - windings by continuous fibres in a direction of action of force and related to it of process of the automated calculation. In article the uniform way of the task of surfaces of dependent sections with curvilinear forming and a way of solid-state modeling of the environment received by methods of winding or the calculation is developed. Keywords: spline; normalized spline; geometrical modeling, approximation, solid-state modeling. |
|
Economics and management | |
One of the main reasons of delayed "transition period" in reforming the Russian economy (and aviation branch in particular) is weakness of management, absence of uniformity in approaches to management and the organization of a manufacturing which are characteristic for the western style of a management. It is necessary to generate national style of management on an operational experience in market conditions of the successful enterprises and to fix it in the legal acts and the Russian management ethic code . Keywords: aviation management, crisis, potential, specialist, technical, manufacturing, private-state partnership. |
|
In that article stand questions about the problems of the estimation economic benefit from commercial services space activity realization. The available mechanism and the scientifically-methodical device of economic calculations in the field of space activity aren’t to the full adequate to complexity and perfection of created space systems. Creation of essentially new space system demands the account synergetic effect. It is considered as effect of interaction of elements of uniform space system which is characteristic for programs as they assume close interaction much fragments. The synergetic effect of space system is a part of the general social and economic effect of system. It is very important just time. Keywords: Commercial space activity; economic benefit; synergetic effect; commercial potential. |
|
The article presents a methodical approach to formation mechanism of financing production and commercial activities of companies, developers and manufacturers of aircraft and major components in today's financial environment Keywords: aviation industry; innovation and investment processes; sources of financing methods. |
|
One of the consequences of transferring the aviation industry and civil aviation to free market is a significant reduction in capacity utilization with the background of actual decentralization of management and the absence of an active and comprehensive support to the industry by the state. This leads to the inevitable loss of technology, personnel and innovative capacity. The difficult situation has arisen in a number of related industries, such as the production of special construction materials. Restoring competitiveness of the industry in a global economy needs the active innovative transformation and optimizing the parameters of the innovation cycle in the enterprise. Solution to this problem requires an analysis of general patterns of innovation and deep knowledge the features of the industry. The article discusses the innovation cycle and the static ratio of innovation process at different levels, which can help to solve different issues of effective management of the industry. Keywords: base and improving innovation, intensity and effectiveness of innovation development, innovation cycle, the static ratio, the level of innovation, degree of innovation orientation of the economy, the balance of innovation at different levels. |