2014. № 78
Mathematics. Physics. Mechanics
V.Z. Vlasov generalized problems on stress state of cylindrical vessel under hydrostatic pressure in the case of physically orthotropic material
In recent times in various areas of engineering, new materials are increasingly being used to construct structures of various purposes with high limiting characteristics. This trend is particularly true in aviation and aerospace industry where more stringent requirement of designing high strength to weight ratio structures are forcing the designers to boldly introduce new advanced materials despite their relatively high cost when compared to the traditional materials. This article is devoted to the actual problem of strength of thin-walled aviation and aerospace constructions as well as to the study the influence of orthotropic material on its stress-strain state. We study the circular cylindrical shells constructed from materials, which have three different elastic properties in their three mutually perpendicularly directions, and also are known as orthotropic shells.
The influence of material characteristics, which are based on orthotropic shell structures with hinged pin on the stress-strain state of the structure will be investigated. The structure is subjected to constant hydrostatic pressure along its length corresponding to the horizontal location of the vessel partially filled with liquid.
In the case of isotropic material, various authors have studied the problem of finding the average stress values in shell structures under hydrostatic pressure. The difference in this study firstly, the shells are not isotropic material; secondly, we use differential equation from the general theory of orthotropic shells constructed from the hypothesis of Christoffel-Love. To obtain the most effective solution when considering such boundary problem, we use method double trigonometric Fourier series.
The numerical results on the stress-strain state of orthotropic shells, constructed from hypothetic materials, are represented in the graphical format. Furthermore, the stress values and their normal displacements of the vessels, made from steels 1X18H10T, aluminum alloys D 16T, boron and fiberglass reinforced plastic composites are compared.
Keywords: orthotropic material, cylindrical shell, hydraulic-statics pressure, vessel, differential equation, Fourier series
Investigation of some Statistical Characteristics of the Cauchy Problem for Burgers-Huxley Equation Solution
Burgers-Huxley equation is applied in various areas of science such as nonlinear acoustics, fluid dynamics, biology, ecology chemistry etc. The Cauchy problem for Burgers-Huxley equation describes the evolution of the initial process with consideration of the effects of nonlinearity and diffusion. There are a lot of noise sources of different physical nature. This explains the importance of stochastic solutions of the Cauchy problem for Burgers-Huxley equation investigation.
The Cauchy problem for Burgers-Huxley equation with stationary normal process as initial condition is considered. Solution of this problem is a stationary stochastic process for any fixed value of time variable. As a rule, the practical interest is not stochastic solution itself but its statistical characteristics such as distribution, correlation function. Burgers-Huxley equation is nonlinear partial differential equation. There is no analytical solution of the equation in general case. So, numerical methods of statistical characteristics of Burgers-Huxley equation solution investigation are very important. For fixed value of time variable the solution correlation function is investigated. For some values of equation parameters and under rather general assumptions stochastic solution of Burgers-Huxley equation for fixed value time variables is ergodic in wide-sense process. Thus, the solution correlation function can be obtained from a single sufficiently long realization. This realization is a solution of the Cauchy problem for Burgers-Huxley equation for given value of time variable. The finite-difference method of second order is used for numerical solution of the Cauchy problem. The quadrature formula of second order is used for approximate calculation of the correlation function. Some numerical results are presented and discussed.
Keywords: Burgers-Huxley equation, the Cauchy problem, stochastic process
Reliable thermal protection of a lander and increasing speeds of atmospheric vehicles lay new higher requirement to the adequacy of elevated heat flow values obtained during the flow simulation of structural elements of aircraft by hypersonic flows.
The paper presents a mathematical model describing the processes of heat and mass exchange, as well as chemical kinetics occurring on the surface of the a blunt cone frontal part of an aircraft during flight in the atmosphere at hypersonic speeds. The model is based on discrete analogues solving of Navier-Stokes equations on an irregular grid, together with convection and diffusion equations for each component of the gas mixture and the equations of turbulence model.
The relevance of this work is stipulated by the necessity of maximum precision of heat and mass exchange parameters prediction on the surface of a hypersonic aircraft. Solution of this problem allows optimization of its trajectory, geometry, weigh and layout parameters at the stage of shape design, and accordingly, determine the requirements for the necessary thermal protection of a lander.
To solve the problem of flow around a blunt body by hypersonic flow we selected a blunt cone with the following parameters: taper — 6°, radius of bluntness — 0.0381 m, incident flow velocity M∞ = 25.0. The static temperature of the gas in the stream: T∞ — 265.86 K, pressure P∞ — 53.85 Pa. Mass concentration of molecules: C (O2) = 0,233, C (N2) = 0,767.
The problem was solved in two-dimensional axisymmetric formulation. Calculation of heat transfer processes on the surface was carried out taking into consideration the catalytic activity of the surface. On solving the problem, we used the discrete analogues of the Navier-Stokes equations for viscous compressible heat-conducting model environment, and the radiative transfer equation.
The results of the simulation of flow around blunt cone are presented and analyzed. The reliability of the results was checked by comparing them with the results of previously published studies.
The proposed mathematical model can be used for solving the gas dynamic and thermal problems for the design of heat-stressed structural elements of hypersonic aircrafts.
This work has been supported by grants № 11-08-00828, № 13-08-01328 a, 14-08-00982 from the Russian Foundation for Basic Research.
Keywords: mathematical modeling, Navier-Stokes equations, hypersonic vehicle, gas dynamic, heat exchanger, multicomponent flow
Examination of processes of a hydroelasticity of a ridge pipe ring a lateral view at action of vibration
One of the topical problems of modern machine industry and missile design is the development of engineering methods of computation of operating performances of the complex mechanical systems to secure their reliability and profitability. Machine elements are often subjected to significant vibrational loadings. For the machine elements being the complex mechanical systems various absorption systems are used. For instance, the magnetohydrodynamic dampers can be efficiently applied for the vibration absorption. The considered systems can be modeled by two cylindrical shells enclosed each other with fluid filling between them. This model is useful for explosion engines, flash float gears of navigation, liquid rocket engines, telescopic landing gears, actuating rams with a hollow plunger, and fuel systems of flight vehicles. It is necessary to score that the fluid between shells in such model is damping the eigenvibrations of shells as well as is cooling the shells. For the weight reduction thin-walled shells are used. The outer shell can be geometrically irregular, and the interior one can be modeled as absolutely rigid cylinder. Use of geometrically irregular outer shells with bulkheads not only allows to reduce the weight but also ensures the stability under various vibrational excitations.
The mechanical model of the system with the ribbed pipe of ring cross-section formed by two surfaces of the coaxial cylindrical shells interacting with a viscous incompressible fluid is considered. The exterior shell is geometrically irregular, and the interior one is the absolutely rigid cylinder (see Fig.1).
Fig. 1. Model of a mechanical system.
The mathematical model of this system consisting of partial differential equations of dynamics of the viscous incompressible fluids and the elastic ribbed shell with their boundary conditions is constructed.
The mathematical model is represented by the coupled equations: the non-linear Navier-Stokes partial differential equations, the continuity equation, the partial differential equations of dynamics of both the interior and exterior elastic cylindrical shells of Kirchhoff-Love type, and their boundary conditions. To derive the dynamical equations for the geometrically irregular shell the Hamilton’s variation principle was used. The irregular surfaces of the shell are described by means of generalized Heaviside functions.
The investigation techniques of hydroelasticity problem for ribbed pipes with ring cross-section under vibration loadings are analyzed. The coupled problem of hydroelasticity is solved by means of a perturbation technique and in the guess of the harmonic law of vibration; the dimensionless variables are used. The solution of the equations of hydromechanics is formulated as the monomial small-parameter decomposition where the parameter describes the relative width of the supporting stratum of the fluid, and the monomial small-parameter decomposition with the parameter describing the relative deflection for each shell.
To solve the dynamic equations for the outer shell the Bubnov-Galerkin method was used. The expressions for components of velocity of a fluid, hydrodynamic pressure, and displacements of the exterior elastic geometrically irregular cylindrical shell are obtained.
The proposed mathematical model and research techniques allow to explore the hydroelasticity of a ribbed pipe of a ring cross-section with elastic geometrically irregular outer shell and absolutely rigid interior one with the viscous incompressible fluid between them at presence of the vibration. The solutions of these problems allow one to find the causes of the cavity corrosion of machine elements and increase the strength and a reliability of mechanical systems.
Keywords: hydroelasticity, tube with ring cross section, geometrically irregular shell, viscous incompressible liquid, vibration
Isolation of type Timoshenko equations from spatial theory elasticity plate equations on the base contraction mapping principle
A dynamic spatial theory elasticity equation for the plate is taken as initial ones. The equations are reduced to the dimensionless form and a small parameter equal to the ratio of the plate height to its character length is isolated from themes. The integration of the system of the 12 equations with the 12 unknowns is done with the help of the simple-iteration method permitting to establish the asymptotic small parameter development form for every unknown. The transversal displacement and shear stresses are chosen as the started functions permitting to select the prescribed stress-strain state and by means of them to determine the rest unknowns in the null approximation in turn, and at last the same ones. If the start approximation functions are chosen depending on middle plane coordinates only the problem solution is written by the quadrature. The same values being calculated in the first approximation give the correction of the null approximation values. The isolated plan equations have the hyperbolic type whereas bending equation are of hyperbolic type with respect to shear stresses and of parabolic type with respect to transversal displacement. In strength of this the obtained equations might be useful for the chock type solution taking into account the wave processes. If a load vary slowly along coordinates the problem solution is reduced to the slowly vary unknowns function of stresses and displacements. In this case the problem is reduced to the problems sequences in such a way that the output data of the one problem are the input data for the next one.
Keywords: contraction mapping principle, Timoshenko theory, oscillations, plate theory, small parameter
The problem of viscous incompressible liquid layer movement in a flat channel with the walls formed by a vibrating stamp and an elastic plate is set up and analytically solved in a two-dimensional problem’s statement. The liquid’s movement is excited by the known pressure difference at the butt ends. The law of the stamp movement as an absolutely rigid body is also considered as a known function. The problem statement results a coupled system of the Navier-Stocks equations, the continuity equation for viscous liquid layer, the plate-stripe dynamics equation, and the boundary conditions. The boundary conditions of liquid adhesion to the channel walls, of free liquid leakage at the butt ends and the ones of simply support of the plate at the butt ends make up the boundary vaue problem’s statement. The complex of dimensionless variables of the problem is formed; the relative liquid layer thickness and the stamp oscillations amplitude are taken as small parameters. The linearization of the problem by means of perturbation method is made. The solution of the linearized problem for established harmonic oscillations regime is carried out. The form of the plate deflection is approximated by the trigonometric series of longitudinal coordinate. The laws of elastic channel wall deflection and liquid pressure in the channel are found.
The solution is carried out by the means of the perturbation method for the established harmonic oscillations. The pressure distribution in the liquid and the deflections of the channel wall are found. The frequency dependent deflection amplitude and the dynamic pressure along the channel are obtained, and the investigation of the hydroelastic oscillations of channel walls is provided. On the basis of the performed calculations it is shown that the keeping of two or three members of the series in the solution is quite enough for practical purposes. Considering each consecutive series’ member leads to the emergence of additional resonance frequency of the plate oscillation.
Keywords: hydroelasticity, viscous liquid, oscillations, beam, oscillating stamp, perturbation method
We carried out commutation of gaps of arbitrary shape experiments in electric breakdown in atmosphere mode. The length of the gaps formed by exploding wires was up to 1.9 m with energy stored 200–4100 J and charging voltage less than 11 kV. With this, two modes are possible: exploding wire mode without electric breakdown, and electric breakdown mode (EB restrike) in the channel formed by exploding wire with current pause less than 250 ms. The paper presents voltage and current oscilloscope traces at discharge gap, as well as luminescence for both modes. The values of channel resistance are given for breakdown mode. Based on experimental results we discuss the breakdown mechanism and streamer initiation within the discharge gap of 5.3—17kV/m. Geometry evaluations of individual overheated copper drops plasma formations are carried out. We also discuss wire explosion products formation — large aerosols with participation of copper oxide particles (CuO, Cu2O), as well as current flow character during the breakdown. The paper presents estimation of channel temperature and average speed of its expansion. It is shown that with specific energy of 600 J/m inserted into the channel the electric breakdown simulates real processes in the trigger type lightning, that is artificial lightning used for thin wire channel formation in the direction of a thunderstorm cloud during small rockets launching.
Keywords: conducting channel formation in the atmosphere, exploding wire, current pause, electrical breakdown, streamer, aerosol
Nonlinear waves in viscoelastic cylindrical shell with a viscous incompressible fluid and surrounded by an elastic medium
The equations describing strain waves dynamics for coupled hydroelasticity problems, including the dynamic equation for geometrically nonlinear viscoelastic shells surrounded by elastic media and accounting the dynamic equations for viscous incompressible liquids inside shells, are derived by means of asymptotic methods with appropriate boundary conditions. The obtained equation generalizes the well-known equation of Gardner. Accounting the small radius of the shell midsurface as compared with the strain wavelength, the dynamic equations for viscous incompressible fluids are asymtotically transformed to the classical equation of hydrodynamic lubrication theory.
In this paper, the Cauchy problem for the derived equation is solved numerically taking into account the effect of the fluid and of the surrounding elastic medium. The finite difference schema is based on the construction of an overdetermined differential equations’ system. These ones are approximating the integral conservation laws and the integral relations between the unknown functions and their derivatives. As a result, the finite difference scheme is defined as a compatibility condition for this system and automatically provides the integral conservation laws for the areas composed by the basic finite volumes.
The fluid filling the shell that is immersed in an elastic medium result the increasing or decreasing of the strain wave amplitude, depending on the Poisson ratio of the viscoelastic medium. On the other hand, the elastic medium surrounding the shell increases the velocity of the nonlinear wave deformation.
Use of the proposed model significantly enhances the possibility of the experimental data analysis for the significantly nonlinear dynamical systems such as fuel and cooling systems for aerospace engineering, etc..
Keywords: non-linear waves, viscous incompressible liquid, viscoelastic cylindrical shell, surrounded by an elastic medium
Axisymmetric forced vibrations of elastic circular three-layer plate have been studied.
The plate is fixed on elastic base. Because of the symmetry of the problem the tangential displacements in the layers are absent. On the contour of the plate assumes a rigid diaphragm that prevents relative shift layers. The padding between the carrier layer is considered easy, that allows us to neglect his work in the tangential direction. Elastic base describes the Winkler model. To describe the kinematics asymmetrical thickness package adopted broken normal hypothesis.
Solution of the problem is contained in a cylindrical coordinate system. External vertical load acting on the plate is not dependent on the angular coordinate. Applied to the plate following types of loads: locally parabolic distributed on a circle with a given radius of the concave parabolic uniformly distributed local rectangular.
Forced transverse vibrations of circular three-layer plate associated with the elastic foundation, described by a system of differential equations derived from the variational principle of Hamilton. External load and the desired solution are presented in the form of expansions in series.
Numerical results are obtained for the contour clamped circular three-layer plate, unbound and bound with a base of medium hardness. The resultant force and the parabolic rectangular loads assumed to be equal.
The dependence of the change in the deflection of circular three-layer plate associated with the elastic base of medium hardness, the radius of the spot the local distribution of the dynamic load have been found. In the absence of an elastic foundation deflections vary little. A plate associated with a deformable base deflections when distributing loads on the entire surface increases approximately twofold.
Deflection reaches maximum values during operation load on the entire outer surface of the plate. Maximum deflection of the convex parabolic load time exceeds the amount of deflection of a rectangular load of 1.35 times. Consequently, for the same magnitude of the resultant convex parabolic load more dangerous than rectangular, as in the plate causing Larger deflections. This effect is observed for the plate associated with an elastic base, both with and without it. In the absence of an elastic foundation deflections vary little. A plate connected with a deformable base deflections when distributing loads on the entire surface increases approximately twofold.
Numerical results are compared with the case of the local surface load of rectangular shape.
Keywords: three-layer circular plate, elastic base, oscillations, parabolic loading
The stress-strain state of a spherical shell of Timoshenko type and elastic isotropic half-space in process of their impact on an arbitrary time interval of interaction is investigated. In this case the contact area changes dynamically. The movable spherical coordinate system is used for the shell and for the half-space the non movable cylindrical coordinate system is used. Contact occurs in frictionless circumstances.
Statement of the problem involves the equations of motion of the shell and the half-space, the physical and geometrical relations, the coupling equations for displacement and elastic potentials, he coupling equations for stresses and elastic potentials, equation of motion of the shell as a rigid body, boundary and initial conditions.
To solve the problem the influence functions for the half-space and spherical shell is used. First of them received explicitly earlier. Second of them is a normal displacements of the shell as a solution of the initial-boundary value problem on the impact of the normal pressure on the surface of the elastic shell, given as the product of the Dirac delta function depending on the angular coordinate and time. To construct the influence functions the expansions in series of Legendre polynomials and their derivatives are used.
The initial system of dynamics equations of the shell is reduced to the infinite system for the unknown coefficients of expansions, which are depend on time and angular coordinates. With the help of the Laplace transform in time and further treatment the solution of this is system is constructed.
A system of governing equations, the basic equation of which follows from the boundary conditions and integral representations of normal displacements of the shell and the half-space, based on the principle of superposition is developed. The kinematic relation between the radius of the contact area and the depth of penetration of the shell, the equation of motion of the shell as a rigid body written in integral form, and the initial conditions are completing the system.
A numerical-analytical algorithm for solving a system based on the method of quadratures using the formulas of Gauss and Simpson is developed and implemented. In the case of singular integrals the method of weighting coefficients and canonical regularization is used.
As the results of the calculations the graphs of the distribution of the contact pressure and normal displacements are shown. Dependences of contact pressure and normal displacements on time in a front point of the shell are also presented. The analysis of the received results is carried out.
The obtained results can be used in the aerospace industry in the cases of predicting the results of hard landing of the space landers on the ground.
Keywords: non-stationary contact problems, spherical shell of Timoshenko type, elastic half-space, influence functions, integral equations, quadrature formulas, canonical regularization
Aviation technics and technology
Purpose — Many authors considered direct problem of obtaining wing-lift coefficient dependence on incidence angle, using a well-known airfoil dependence based on modified theory of lifting line. The first purpose of the study was to clarify the limits of applicability of this mathematical model in case of nonlinear lift dependencies. The second purpose was to develop methods for solving inverse problem of determining the aerodynamic characteristics of the airfoils based on the results of wing model tests in wind tunnels, taking into account the nonlinear dependence of the lift on the angle of attack.
Design / methodology / approach — Based on the modified theory of lifting line we developed a two-step iterative algorithm for solving direct problem for rectangular wing of finite span. To verify it an alternative optimization method was developed based on the genetic algorithm, which allows determining the global optimum. Extensive computational studies led to the conclusion of the modified theory of the lifting line approximate nature, in contrast to the classical Prandtl theory.
Findings — Introduced is the concept of acceptance criterion, which allows satisfying the hypothesis of flat sections with a reasonable accuracy and finding the approximate solution of the direct problem. The limits of applicability of the modified theory are discussed. On the basis of an algorithm for solving the direct problem, an optimization algorithm for solving inverse problem was developed in trust region of wing angles of attack.
Practical applications — The results of this study will be used in recalculations of wings test data.
Originality / value — This study establishes that for mathematical model based on modified lifting line theory, the trust region of wing attack angles is limited by a near vicinity of critical angle of attack.
The paper describes a straightforward procedure to recalculate wing aerodynamic characteristics to get airfoil characteristics for later use in the calculation of the main/tail rotor.
Keywords: airfoil, wing box, lifting line
This paper presents a study on two methods of constructing spatial aircraft trajectories: simple method of trajectory planning and Taranenko’s direct method. Both methods are based on the inverse dynamic concept.
We need to find trajectory and control variables for an aircraft from initial point
to terminal point for a specified time interval with initial control vector and final control vector . In this study, three-dimensional point-mass model of an aircraft with zero sideslip angle was used.
With simple method of trajectory planning, solving boundary value problem of flight dynamic accomplished without control and state variables constraints. This method assumes that three coordinates of the aircraft represented analytically as functions of argument τ
Here — initial and final time. specified time interval.
Aircraft’s coordinates approximated by
Here ki, hi, wi — coefficients, а — basis functions.
The coefficients ki, hi, wi were determined by satisfying the boundary conditions and system dynamic equations.
With Taranenko’s direct method, the problem was solved with both control and state variables constraints. The trajectory optimization problem was transformed into a nonlinear programming problem and then solved numerically using an appropriate algorithm.
In example cases, two methods were applied with the same boundary values. The comparison of two methods is given. Analysis of the results leads to a concousion that the simple method of trajectory planning can easily produce unrealizable trajectories and thus it cannot be used for onboard computations.
Keywords: boundary value problem, inverse dynamic, trajectory planning, direct method
Dynamic deformation of structural elements of flying vehicles at their emergency impacts with barriers
An emergency disconnection of a flying vehicle from a carrier vehicle is often caused by destruction of connection points or by an abnormal function of launching device. The emergency disconnection at stages of landing or starting runs results the impact of the flying vehicle to a runaway surface. To predict the impact’s effect and the explosion or ignition danger, the dynamics, the deforming state, and destruction of the vehicle have to be estimated.
The technique and the results of the numerical simulation of the dynamic deformed state of the flying vehicle structure are performed for the medium velocity impact with the rigid flat barrier after the emergency separation from the carrier at starting and landing run stages. The problem of transient dynamics is solved by the finite elements method using the LS-DYNA system and the explicit integration approach. The finite elements of shell type with one point of integration are used; the deformation curve is by the bilinear function approximated. An initial velocity and an incidence angle are used as input data for the dynamics problem for the structure with known geometrical, mass, and stiffness properties.
The eigenfrequencies and eigenmodes of the existing vehicle as well as the accelerations for some structural elements in the transient process resulted by the impact are computed and compared with the semi-nature tests data. The numerical simulation has shown that the structure destruction occurs on compartments’ joints so that corresponds to the experimentally observed destruction. The obtained correlation between the computational and experimental values of eigenfrequencies and impact accelerations confirms the usability of the developed numerical technique for the simulation of impact interaction of flying vehicles structures and barriers.
The developed numerical simulation technique allows one to estimate the dynamic stress state parameters for various flying vehicles at emergency impacts.
Keywords: airplane, aircraft, accident, finite element method, dynamic response, acceleration, impact, barrier, bilinear material model
Accounting requirements for aeroservoelastic stability of maneuverable unmanned aircraft during the stage of electromechanical rudder drive design
The purpose of this study is to propose an electromechanical rudder drive design method. Main objective of this method is to determine critical values of rudder drive design parameters on stage of conceptual design and reduce time expenses required for experimental obtaining of the aeroservoelastic (ASE) stability margins.
A mathematical modeling approach has been chosen to solve the rudder drive design problem. The rudder drive model has been developed in MATLAB/Simulink environment corresponding to block diagram of real electromechanical drive. The frequency response function (FRF) has been measured from real electromechanical rudder drive and then compared with calculated FRF obtained from Simulink to validate the developed rudder drive model.
During the validation process it is found that the mathematical model of a rudder drive reliably reproduces the characteristics of the real drive and thus can be used to preliminary estimate the ASE stability margins.
The developed model has the potential for further improvement, for example to include new tasks such as rudder drive stability regions formation for several design parameters. Further development of the model should be directed towards the detailed backlash simulation in reduction drive. To solve this task reducer should be represented as two (or more) gear wheels which are moving separately from each other in backlash.
The design method described in this study can help to replace a part of the experimental studies with mathematical modeling. Also with the help of this approach it is possible to reduce the risk of ASE instability in the final stages of design, thereby avoiding costly changes to the automatic control system and rudder drives to eliminate shortcomings.
Keywords: aeroservoelastic stability, unmanned aircraft, electromechanical rudder drive, conceptual design
The purpose of this paper is to find the relationship of risk, threat and vulnerability protection of an object.
For the degree of the threat to civil aviation estimation it is necessary to solve two fundamental problems: to estimate the threat and deal with the risk.
It is obvious that the establishment of measures necessary to deter high-risk associates with high costs. Consequently, these measures should be realized in the case of maximum necessity. This is the basis of the risk management concept.
Let us specify the concepts necessary to this concept implementation: threat, danger, risk, aviation security risk factor.
It should be understood that the management of threats and risks is a difficult task, which involve not only aviation security special services, but also government agencies.
It is necessary also to understand the factors affecting on the probability of selecting a particular object by an offender.
From the results it obtained in this work a conclusion can be made that the main activity of the aviation security to protect the object against acts of unlawful interference is to reduce its vulnerability due to the adoption of measures increasing the probability of parrying of some kind of unlawful interference committing.
The factors having impact on the degree of protection of the object, include: the effectiveness of special technical means used to ensure aviation safety, efficiency technologies used, the quality of facility personnel. These factors are necessary to enhance the security of the object. The main characteristics of the process of aviation security organization are stability, efficiency, continuity and secrecy.
Without sufficient capacity to prevent threats it is possible, however, to reduce the risk to an acceptable level by creating adequate protection measures and thus providing risk management on the basis of systematically organized protective procedures. The important
Important components of the risk assessment process are control checks to verify aviation safety provision activities compliance to international standards, as well as control of completeness and quality of aviation security measures, taking into account the current level of threat.
Risk management in the socio-economic system, which is characterized by the presence of constraints in terms of available economic resources, is the process of optimal allocation of eligible costs of risk reduction, providing the level of security attainable in economic and social conditions of the existing society, adopted as an acceptable level.
Keywords: aviation security, risk, risk management, vulnerability, risk factor
The paper analyses current situation with global sea surface monitoring system development implementing high-altitude reconnaissance UAVs. We present approaches to rational design algorithm for aerial reconnaissance over the sea UAV image building with allowance for weight and tactical criterions. Complexity and relevance of iterations in UAV design algorithm are noted. We believe that it is expedient to select takeoff mass as a criterion of optimality, since it can be considered as a universal criterion of optimality. We also disclose UAV complex performance evaluation approach within the framework of surveillance operation as an aggregate of operation fragments assessments interchanging each other. The paper gives image design definition and discloses its main content. It also touches upon the importance of resolution index of target equipment for imagery intelligence. The paper gives recommendations on content of the target equipment providing required resolution afield, and presents the estimation of efficiency results of typical target equipment based on the criterion of object of intelligence t recognition probability.
One of the main tasks of image shaping is analysis of reconnaissance objects, their air defense, electronic warfare means, and indicators of visibility. It is important to analyze the weather conditions and sea surface state dependence of aerial reconnaissance efficiency. It is necessary to develop a mathematical model of complex operating effect to substantiate requirements to UAV trajectory, to the structure and parameters of the target equipment. It is essential to create UAV aerodynamic model, UAVs weight model, geometric layout, UAV effective area of scattering calculation model, layout and alignment models, as well as other models within the framework of the selected reference image. The paper describes an approach to aerial sea reconnaissance UAV image forming algorithm with allowance for target reconnaissance equipment. It presents estimation methodology for target equipment optical channel and on-board water-borne targets radar installation effectiveness. Simulation results show that sea reconnaissance tasks solving is possible one include both optical and radar channels into target equipment. Optical channel must have the following parameters: matrix dimensions — 30 mm × 30 mm; number of pixels in matrix row — 3000; focal distance — 200 mm. Radio channel antennae gain should be in the range from 3000 to 4000, and transmitter power — from 2 to 4 kW.
Keywords: sea monitoring, unmanned aerial vehicle, monitoring equipment, designing, design parameters
Space technics and technology
Present-day space projects of large-scale power plants are based on large-scale structures of the frame and frameless implementation. These are solar battery (SB) frames, centrifugal thin film SB, solar sails and reflectors, frame multistage refrigerators and drip emitters, cable antennas. Side-by-side with solar cells characteristics improvement is
Improvement of SB load-bearing panels (frames and substrates) using new composite materials and mechanisms to control their deployment goes side-by-side with solar cells characteristics improvement. American and Japanese solar power stations (SSPS) carcass constructions reach sizes of up to five kilometers.
Rigid frame trusses imbedded in these projects, as well as towing vehicle with a rigid frame size of 400 ´ 400 m solar cell and a capacity of 15 MW meant for an expedition to Mars design study carried out by Keldysh Center together with RSC «Energia» are not based on any experience of creating such large structures in space. The structures of similar scale (stadiums, or supermarkets) have not been created even on Earth surface. The inability of full-scale ground development test and accounting for weightlessness factors as well as deep vacuum impact on structure deployment process are principal rigid frame trusses drawbacks. There are numerous examples of the inadequacy between ground testing without regard to weightlessness and space experiment.
Creating a large space structure with life time of about 15 years with high precision surface and its orientation as well as the existence of such structure in a flow of space debris and meteorites presents rather difficult problem. Centrifugal solar cells have a number of significant advantages over their carcass analogs. They are not sensitive to meteorite hazard in particular, and may find efficient application for space vehicles in wide power range: from satellites with higher energy consumption of 30 ... 50 kW to SSPS with power from 1 to 10 GW. Centrifugal solar cells can be used also for Mars expedition power system, since their feasibility and specific characteristics (kW/kg) 3 to 5 times outperform nuclear power installation. They have no high-temperature loops of fissile uranium; do not require radiation protection; do not lead to disastrous effects in the case of failures; do not require special utilization, as well on-stream serviceable and repairable.
Long-term program of space experiments on the ISS includes the preparation and conduct of the orbital experiment «Banner SB» with centrifugal membrane structure SB 6-kW, hydrogen-oxygen electrochemical storage of electric power and oxygen-hydrogen low-thrust rocket engine. Innovative oxygen-hydrogen concept is widely developed all over the world. It lies in the development of oxygen and hydrogen production system by means of electrolysis of water on orbits, storage systems of these gases, as well as missiles fueling systems developing. Centrifugal SB can serve as an effective basis for future propellants production factories in space, as well as for a wide range of promising applications.
Keywords: space solar power station, centrifugal fiber lasers, solar pumping, microwave radiation
Aerospace propulsion engineering
The development of the basic module schemes for the dimension-type series of power plants based on the air-aluminum chemical current sources
Currently, there are a lot of works developing the power plants (PP) based on the aluminium-air (AA) mechanically rechargeable chemical current sources (CCS), which have high specific energy and profitable economical and operational characteristics. For this kind of PP it is reasonable to create a functional dimension-type series of the AA PP. This paper examines the basic module diagrams for the modular dimension-type series and evaluates the energy and mass exchange characteristics as well as the energy loss characteristics for power plants of various schemes.
During the development of the basic diagrams of the PP and its service systems, the unique specifics of the AA CCS and the special properties of the reaction products were considered in addition to the usual approaches. Since the consumed materials in the AA CCS are the aluminium, water, and oxygen, they should be constantly fed into the reaction zone and the reaction products should be removed in case of a long constant work. Accordingly, the block diagram of the PP based on the AA CCS with a circulating electrolyte should have a range of subsystems which will provide the energy and mass exchange.
The fundamental property of the AA system is a high buffer capacity of the alkaline electrolyte, i.e. a significant part of the water can be consumed from the electrolyte without further water supply, given that the electrical characteristics of the current source change insignificantly. Considering the high electrolyte buffer capacity, in several cases the water storage and supply system can be excluded from the PP. Therefore, another scheme with a circulating alkaline electrolyte system is proposed. An integrated block diagram without circulation (the so called filled scheme) is also examined.
A light scheme of the PP based on the AA CCS with the neutral, saline, electrolytes is examined. Since there is no corrosion at the no-current mode in the AA CCS with the neutral electrolytes, it is not necessary to pour out the electrolyte in the intervals between the PP operations.
For the proper choice of the basic module diagrams of the dimension-type series, the energy and mass exchanges in the AA CCS have been evaluated and the energy loss has been compared in different basic diagrams. This paper also describes the main characteristics of the basic modules of the AA PP.
It is shown that the main factor limiting the power rate of the basic modules is a maximum reachable power rate of the single battery which is determined by the technological limits of production of the large area gas-diffusion cathodes and the possibility of providing the proper conditions for the energy and mass exchange.
As a conclusion it can be said that based on the main determinative characteristics it is possible to create 23 modular dimension-type series, which include 35 basic modules in each series. Besides, the basic module can include 16 or 18 batteries depending on its power rate. Also, the optimal schemes of the PP basic modules are chosen in this work.
Keywords: electrochemical cell, dimension-type series, electric power plant, basic module
Development of a generalized mathematical model of calculation and designing of combustion chambers of vertical counter flow type.
Power and heat-power facilities state-of-the-art requires environmental, energy and economic efficiency enhancement of the work process. In its turn, these requirements are associated with
The most promising solution to the problems mentioned above is the application of combustion chambers of vertical counter flow type.
Our research pursues an objective of developing science-based methodology integral characteristics calculation to design various modifications of suggested combustion chamber for practical application.
For our research we choose the device in the form of a two-stage two-zone chamber as a model for theoretical study of the fuel combustion process.
The feature of this kind of the combustion chamber lieы in the fact that it combines the main features of working process and construction elements of the single-stage, two-stage and two-zone combustion chambers. After the investigation of the combustion chamber of the complex type, it is easy to transfer the obtained results to one-stage, two-stage and two-zone combustion chambers.
In the work we obtained parametrical equation linking thermo-dynamical and gas-dynamical parameters of the main elements of combustion chambers. This equation allows obtaining the integral characteristics of the two-stage two-zone combustion chamber and estimating the influence of each main element, that combustion chamber consists of, upon its output parameters and construction. This equation includes coefficients of the air surplus and the combustion completeness in each of main elements. As a result, the work gives the linkage between the integral parameters of the combustion chamber. We found out that the product of all the integral parameters of the process is equal to unity. This equation provides the implementation of the ten variants of the constructive scheme of the combustion chamber for the relevant working modes, i.e. we can choose different modification of the combustion chamber.
Keywords: engineering, air-jet engines
The paper presents physical and mathematical model, algorithm and description of the program complex meant for calculating thermal state of a cooled micro rocket engines block, used to operate space objects. The micro engines block looks like a plain profile box of the engines (every one has length no more 15mm) with two cross cooling channels that are situated next to combustion chambers and nozzles, where liquid or gaseous refrigerant can be used.
The thermal energy source is introduced by high-temperature gas-dynamic flow with stagnation temperature of about 2000 degrees Kelvin. Under these conditions, metal structure of micro engines block has a temperature limitation. As a result, heat energy discharge using a refrigerant is necessary. With this, the larger the velocity of a refrigerant the larger is the discharge.
In order to define thermal state of the micro engines block it is necessary to solve heat transfer problems between hydro-dynamic and gas-dynamic flows as well as between multiply connected bodies bounded with uneven boundaries: — non-viscous flow in the combustion chamber and nozzle of the micro engine;
The paper presents a new method for numeric solving of combined heat transfer problems and problems of three dimensional non-steady heat transfer. We used a method of reflection of multiply connected area with any boundary into classical form area (rectangle, parallelepiped...), where it is possible to make up a through orthogonal grid. At that, coordinate lines can enter and leave the calculated area any arbitrary number of times.
The program complex for calculating thermal state of the block of cooled micro rocket engines was designed using the presented above algorithm. Namely, to determine heat-exchange parameters of gas-dynamic flows in gas-dynamic and cooled channels, as well 3D non-stationary thermal conductivity in multiply connected regions with arbitrary boundaries. We obtained and analyzed multiple numerical solution results.
Keywords: micro rocket engines, cooling canals, heat, heat gas-dynamic flow, conjugate heat transfer, conjugate heat transfer, break down of the numerical method, immersion method, gas-dynamic parameters, 3D non-stationary temperature field, special software
Control and navigation systems
Analysis of accuracy estimation of own coordinates in the radio navigation systems with small bases between transmitters
One of the possible solutions of the determination position of aircrafts by using local ground-based high-precision radio navigation systems is considered in the article. This system consists of 4 evenly distributed on a circle of 50 meter radius ground-based transmitters, a control-correction station and an on-board receiver. The synchronization of signals is produced by operation of the control-correction station. Estimation of coordinates is performed on-board the aircraft.
Analysis of accuracy coordinates estimation when aircraft is far from the transmitters is shown in the paper. Characteristics of accuracy estimation of local coordinates are investigated for a few types of algorithms. The use of non-filtering Least-Squares Method (LSM), Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) is considered in the article.
The influence of divergence of the receiver’s clock has been examined on accuracy estimation for two types of measurements, i.e. range and difference pseudo ranges. In the first case, divergence of the receiver’s clock is included in state vector, while, in the second case, divergence is made up for forming of the difference pseudo ranges.
Results of simulation show the equal accuracy of LSM algorithms with pseudo ranges and different pseudo ranges. EKF and UKF with pseudo ranges measurements give more than twice better estimate in comparison with EKF and UKF with difference pseudo ranges measurements. This effect achieves because the influence of clock divergence in pseudo range methods include in the state vector. Results of simulation also show equal accuracy of EKF and UKF algorithms with the same measurements.
Keywords: nonlinear filtration, coordinate estimation, local radio navigation systems, UKF, unscented kalman filter, EKF, extended Kalman filter
Determination of the relative significance of efficiency and safety of air traffic with the aid of the inverse problem of the linear programming
This work is devoted to the solution of the inverse problem of linear programming to establish weight coefficients of the importance, effectiveness and safety of aircraft movement in echelon of landing approach. The air traffic controller knows how he should act in a concrete case, but he does not know the mathematical model of the criterion. In one case he makes alternative decisions on reduction, or increase of a distance between planes due to lateral maneuver or increase in draft. In other cases at increase of risk of air traffic, the air traffic controller prohibits entry of one of the planes into an echelon and gives command to leave to a repeated circle. Therefore expediency arises to reconstruct the criterion by separate examples of optimum behavior and then implement them in general cases. This criterion, as well as restrictions, can be presented in the form of linear convolution of parameters. The variables by nature are not negative, and selected decisions are alternative. Thus the process of selection of the most rational decision can be treated as finding of one of the vortexes of convex polyhedron. It can be done by means of a known direct problem of linear programming. The inverse problem sets the group of linear inequalities in the form of restrictions on a set of variables. The polyhedron vortex taken for the best decision with coordinates is also known. It is required to identify criterion coefficients whenever possible more precisely. The paper offers the reverse simplex method of identification of unknown criterion function of criterion in the form of linear convolution if the result of the decision at known restrictions on variables in the form of linear inequalities was set. The reconstruction of criterion function by means of the received interval estimates allows using the solution of a direct problem with new conditions — or in automatic mode, or as a prompter, reducing thereby influence of a human factor. Accuracy of the solution of the inverse problem depends on what vortexes of a polyhedron, and how many of them become known as a result of rational alternative actions of the person taking the decision that can be used for identification. The example confirming operability of the offered algorithm is presented.
Keywords: flight safety, linear programming, inverse problem of parametrical optimization
Development of the control system of new generation leak detecting equipment for testing elements of rocket and space technique
One of the major tasks of rocket-and-space equipment production is ensuring structural continuity. Thus, all systems and elements of the rocket-and-space equipment undergo tests for tightness so that to detect and eliminate all leakages appeared in the course of production. For leakage detecting one can use highly sensitive leakage detectors of various types from either domestic or foreign producers.
Moreover, performance capabilities of all leakage detectors listed in this paper do not satisfy the requirements placed on industrial leakage detecting equipment having a number of special properties. Design of such equipment is the subject of the present work.
The paper presents the main features of industrial leakage detector in addition to its high sensitivity and permissible measurement error that are of great importance while hermetic tightness control of different reservoirs.
The developed prototype of the industrial leakage detector allows operation within the range from 3.3211∙10-27 to 4.9816∙10-25 Pa (from 2 to 300 Da), it is equipped with oil-free forepump system with productivity of 15 m3/hour and operates under control of a hardware-software complex on the basis of the industrial tablet computer and the controller. The total error of working gas consumption detection makes less than 40%. This error can reputed rather small, considering that calibration leakage error, as a rule, is more than 20%.
Extorr Inc company Extorr XT-300 analyzer as a a part of a hardware-software control complex of a leak detector takes measurements of pressure of helium mixture in the chamber and presents the results in the form of partial pressures (Torr) by atomic unit within the range from 0.5 to 300 Da. To determine helium partial pressure we select measurements corresponding to the mass of helium with due account for peak degradation. Namely, partial pressures are measured within the vicinity of weight 4 (helium) by which integrated value is calculated. Background and noise components are filtered by averaging
Helium stream (m3Pa/s) is defined by means of the developed experimental calibration function f(x) in the form of (1)
According to the results of the measurements taken at tests there we calculated coefficients of function f(x). Their values are: a1 = 0.0058, а2 = 1,5979∙10—11, a3 = —4∙10—6.
The developed leakage detector prototype has passed preliminary tests and showed satisfactory performances. The subsequent installation refinement under conditions close to production will allow making necessary improvements to its hardware and software parts, and producing pilot batch for pilot industrial application.
Keywords: leakage detector, mass spectrometry, vacuum pumping
Technical cybernetics. Information technology. Computer facilities
Application of non-adaptive neural networks for solving of the piecewise constant independent component analysis problem
In this paper we consider the possibility of applying non-adaptive artificial neural networks (ANN) to solve non-stationary problems like piecewise constant independent component analysis (ICA). Usually adaptive ANNs are applied to such problems but this leads to large computational costs in comparison with non-adaptive models because of requirement to calculate higher-order statistics. The idea of the proposed method is based on the fact that while solving the piecewise constant problem by non-adaptive ANN, we can try to detect changes in problem conditions with consequent retraining of the network for compliance to the new conditions. If it is possible then we can significantly reduce computing costs on time intervals when conditions are constant.
The proposed method implies that we need to automate the retraining process. To achieve it we have to introduce some metric which describes the presence of changes in problem conditions. We should also adjust the learning rules of the ANN model. We show in this paper that piecewise constant ICA problem with Poisson-like independent components can be solved using non-adaptive model  with metric based on average neurons activity and original learning rules with only learning rates affected. The model obtained as a result was tested on the piecewise constant version of the «Foldiak bars» problem and has proved its efficiency.Thus the proposed method can be applied in some cases to produce adaptive ANNs from non-adaptive models. However generalization of the obtained results to identify applicability conditions of the method as well as a general algorithm for ANN conversion requires further research. Furthermore convergence problem for generated models seems to be complicated enough due to the large number of influencing factors.
Keywords: artificial neural network, adaptive models, independent component analysis
Electronics, Radio and Communications
The article introduce the conception of the automation of the system engineering of the informing radio systems (IRS), which have been constructed according to the modular approach. The purpose of the work is the terms’ reduction and efficiency upgrading of the designe choice by using adopted modules of high productive preparation as element of IRS’s structure.
Methodology of the proposed engineering conception is based on the integration of the various dedicated CAD in the unified design cycle, which includes system model’s forming, system engineering on the signal level, covering the structural elements IRS with the modules of high productive preparation, input rating and ranking of structural vary according to the input parameter. As a mathematic base of tasks solving should be used strict hierarchical Petri-net,which allow to provide adequate introduction IRS on the different levels of functional hierarchion. Data-driven design of the design cycle is completed by the system of informational support (SIS). By information content SIS is above the standard PDM-systems, as SIS integrate the information of diverse task-orientated CAD ( schematic, constructive).
The principle result of the work is the route of the system designing automation, which is based on the integration of the task-oriented CAD, which allows the usage of the modules of high productive preparation in the project.
Consequentle introduced conception of the automation of the system engineering IRS, which based on the integration of the diverse task-oriented CAD in the unified design cycle IRS, provides efficiency upgrading of the IRS engineering due to the consumption of modules of high productive preparation.
Keywords: automation of the system engineering, informing radio systems, approach modular accord, Petri nets, high productive preparation modules
Air intake devices are one of the main elements of jet engines and aircraft as a whole. In forming the design of the aircraft for intake to meet the following requirements: minimum external resistance , minimal pressure loss during braking flow in the channel , the uniformity of the velocity field and the pressure at the inlet of the engine , the stability of the process air flow , simple structure, low weight , cost and dimensions, low radar cross section (RCS).
The presence of input devices and air ducts in air-breathing jet engines causes a large number of possible layout schemes, the design and layout appearance of the aircraft.
In forming the shape of the aircraft can be solved following problems associated with air intake devices: the definition of rational shape, number, layout, ways to reduce RCS and optimum design parameters.
These problems can be solved by simultaneously solving problems at three levels:
In this paper we formulate the problem of structural and parametric synthesis of design solutions to reduce RCS of the air sampling devices based on complex technical and economic criteria and its particular forms. Proposed a matrix of alternative technical solutions for stealth air intake devices and their design parameters. The structural logic of structural and parametric synthesis image of the aircraft developed. Presented block diagram analysis of the preferred embodiments of masking devices, taking into account their impact on aerodynamic, energy, ballistic characteristics of the aircraft, on the weight, cost, performance visibility and efficiency of the aircraft. Introduced the technique of assessing RCS of air-intake devices. Conducted research on the impact of technical solutions for masking air-intake devices and their design parameters on the RCS.
Keywords: aircraft design, turbojet engine, air intake, stealth, radar cross section
Dependence of information content of aerial objects impulse characteristics upon the location of pulse response
Pulse-by-pulse rearrangement of carrier frequency wave is considered to be one of the perspective aspects of radiolocation development. Employment of frequency hopping techniques improves the range resolution characteristics and allows frequency-hopping signals usage for the purposes of identifying aerial objects through pulse response modeling. Impulse characteristics of aerial objects are of discrete structure which has a significant influence on the signal information content that may decrease the quality of identifying aerial objects. The aim of the article is to study the peculiarities of aerial objects impulse characteristics formation depending on the relative position of scattering centers in radial direction and frequency hopping parameters.
It was investigated that appearance of scattering centers response between the samples leads to the distortion of impulse characteristics. This is reflected in the lowering of pulse response amplitude, in distributing the amplitude between two adjacent samples of impulse characteristic, and in acquiring idle footstalls by the responses, distributed according to the width of impulse characteristic display.
Relative position of scattering centers influences the amplitude of their responses in impulse characteristic. The degree of such impact decreases correspondingly to the growth of distance between the scattering centers. To employ impulse characteristic in purposes of identifying aerial objects during the training of neural network identifiers, one should take into consideration possible distortions of impulse characteristic caused by disagreement of scattering centers responses and samples of impulse characteristic. The investigation revealed that the most effective way to remove the distortions is to increase the range of frequency hopping as well as scale-up of impulses in a pulse packet.
Keywords: frequency characteristic, impulse characteristic, frequency hopping signals, pulse response
Development of onboard avionics systems on the way of integration in a single complex requires the creation of more advanced methods of their diagnostics. Among existing methods, the half split, or dichotomy method, is the most widely used nowadays. The analysis identified the main disadvantage of this method is to ignore the probability of failure existing in any part of the system.
Algorithm of troubleshooting of the ladder-type system can be improved by using of known computing mathematics methods of functions optimization, where the search strategy is to find applicable point that is optimal in case of using of the Fibonacci series to build a sequence of iterations.
Application of the optimal Fibonacci method for optimization of troubleshooting in ladder-type system is in division of the system to such parts that ratio of quantity of elements included in each to be the same as adjacent numerals in Fibonacci series.
The imperfection of the above-mentioned method is that proportion of system division depends on the troubleshooting step number and therefore has to be recalculated again at each step. In this case, instead of the optimal Fibonacci method, the method using golden section is offered. Based on analysis, it is concluded that quantity of measurements by using golden section method is 4 percent less than in the case of using dichotomy method.
The proposed troubleshooting method is very perspective for using in automatic diagnostic of avionics systems to optimize the time for troubleshooting if the quantity of elements of the system is large. The troubleshooting algorithm built on proposed method will reduce the average quantity of measurements during avionics system troubleshooting. It is also possible to combine proposed method with others to improve overall efficiency.
Keywords: diagnostic system, multilink system, Fibonacci sequence, dichotomy method, optimization, algorithm
Economics and management
The insurance of the design risks of enterprises - developers of the ground-based automatically controlled complexes of administration of the automatic spacecraft
Of article Yegor Glebovich’s Zakharenko on the theme «The insurance of the design risks of enterprises — the developers of the ground-based automatically controlled complexes of control of automatic spacecraft», examined to the object of publication in the electronic scientific journal «transactions of the MAI»
In the article are examined questions of estimation and basic methods of control of design risks during the organization of development and experimental production of the ground-based automatically controlled complexes of control of the automatic spacecraft (NAKU KA) in the enterprises of rocket-space industry (RKP).
The methodology of performing work is based on analysis, estimation and subsequent development of detailed control algorithm by the design risks of enterprises — the developers of NAKU KA depending on the scenarios of risky events and taking into account the division of damage into several indices, connected with the degree of the concrete scenario of design risk.
The results of work are:
The results of the article in question can be used for the development of technical-normative documentation for the creation of competitive NAKU KA within the framework of design activity at enterprises in RKP, and also in the design activity of enterprises in the adjacent fields of defense- industrial complex (OPK), and furthermore, in training process the MAI and other VUZ (Institute of Higher Education).
Keywords: ground automated control of spacecraft, project risks, insurance
Development of the network architecture of management of the innovation system in the early stages of the cycle of aeronautical products creation
One of the main elements of the management in the development and implementation of aviation technology are different interaction network measures aimed at the acquisition and transfer of knowledge and technology between the designs, production, research and educational institutions.
Quality, intensity, and the early stages of developing airlines entering into the network of interaction is determined to achieve «breakthrough» improvement options, the long-term effectiveness and efficiency of aeronautical products.
The purpose of the work is to form the processing model of management changes in innovation practice of creating aviation technology considering the evaluation and the choice of the innovation concepts including the system of criteria of innovation attraction of the projects and selection criteria of potential coauthors in science and innovation networks allowing acceleration of the design process, reduce the development time of the new aviation technology, increase the quality of the projects.
The processing model of changes in innovation practice on the early stage of the cycle of aviation production based on the system and coordination-oriented approaches using the Robust Portfolio Modeling, RPM.
The results of the study are: the main stages of the evaluation and selection of projects, management procedures of organization of the selection process of potential scientific and innovation networks, tools for their implementation, the system of relationships between the main stages of the creation’s cycle of aircraft products.
The scope of application of the results of the study are the management and planning of the enterprises working in the early stages of the development cycle innovation products and services, where the initiators and sources innovation developments can be users themselves.
Keywords: innovation, stages of the life cycle, management processes, systems approach, , science and innovation networks, strategy, enterprise
The article analyzes the actual development trends of Additive Manufacturing (AM), applied in the aerospace industry in the United States (US) and Europe.
Ongoing studies on the analysis of AM-technologies are of a generalized nature of popular science, so this paper attempts not only to structure the data obtained by the application in the aviation and aerospace industry (which is the target area of civil and military equipment), but also to give economic assessment of the application of developments. The research materials are selected to demonstrate the difference between AM-technologies and the traditional processing techniques, as well as to point out the features and specifications of parts, components and assemblies produced by various technological methods.
Details and statistics obtained in the course of the study show that in recent years the scope of AM-technologies has become quite important. Due to technological advances and economic benefits of their use, its utilization has become the best indicator of the innovative development of progressively developing countries. Strategically, it’s necessary to track the emergence of technologies and developments in the world of theoretical and practical understanding of the functioning of innovation. US and European countries are leading in the development of new technologies. The study of the results of their work will give more data to support the need for the introduction of
The introduction of AM-technologies has not yet received any adequate attention from the Russian government. Scientific studies are still at a nascent stage and have no systematic approach to the study of AM-technologies. In this direction, foreign development have arrived ahead of the domestic one, besides the studies of scientific nature, an increasing number of techniques are being implemented into production. Therefore, it is advisable to use international experience of creating and operating AM-technologies in industrial sectors such as satellite and engine manufacturing to optimize the production of high-tech counterparts in the Russian aviation and aerospace industry.
Keywords: additive manufacturing, 3D printer, aerospace industry, aero engine building, aviation and spacecraft