Vol 13, No 4 (2014)

Full Issue

AIRCRAFT AND SPACE ROCKET ENGINEERING
Conceptual model of the formation of flying skills in the process of training using flight simulators
Godunov A.I., Kuatov B.Z., Yurkov N.K., Kurtaev S.Z.
Abstract

Mechanisms of perceptive image formation are presented in terms of the proposed paradigm. These mechanisms make it possible to determine the mechanism of flying skills formation in the process of flying personnel simulator training. It is shown that basic and primary training is characterized by the fact that, apart from improving the fundamental knowledge, it leads to the formation and development of perceptive intellectual images that form skills when combined with the knowledge. The process of skills formation consists in operator’s training in fulfilling purposeful mental actions with apperceptive and perceptive sensory and motor images, while the process of knowledge development implies carrying out training sessions on the accumulation of such images. Skills development is similar for different typical situations, but each situation requires particular mental actions depending on the combination and sequence of image variation. Each prospective pilot has his own specific settings of elements of sensory, motor and intellectual systems, so in the course of training elements of these systems are adjusted to each other in accordance with the particular type of flight activity. Such adjustment can also be carried out for typical situations that differ in priorities in the use of the operator’s elements. Possible conflict situations in the process of skills formation and implementation are described in the article. A conceptual model of a set of skills necessary for the use of aircraft and its systems in typical situations is presented.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):7-15
views
Accuracy control method for space complex products at the stage of design engineering
Yelenev V.D., Shuplyak Y.P.
Abstract

The paper discusses the tasks of controlling the required accuracy of space complex products at the stage of design engineering. The product accuracy at the stage of design engineering is viewed as a system characteristic encompassing the whole set of singular requirements for product accuracy defined at the stage of the draft proposal. The method is based on the concept of a standardized accuracy design property which is used to fix the whole number of singular requirements for product accuracy defined by the draft proposal. All the requirements for the product accuracy implemented at the stage of design engineering are reduced to a reference quantity of standardized accuracy design properties defined in the draft proposal to confirm (or disconfirm) their matching each other.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):16-29
views
Choice of design characteristics of «garbage collector» spacecraft with a low-thrust electrojet engine
Ishkov S.A., Filippov G.A.
Abstract

The paper is devoted to the problem of debris in the near-Earth space. We investigate a method of cleaning the space of large fragments of space debris using a “garbage collector” spacecraft with a low- thrust electrojet engine. A mass model of one-shot and shuttle spacecraft has been constructed. A mission trajectory plan is presented that includes the spacecraft flight from the parking orbit to that of debris location, its descent to the surface of the Earth and the return of reusable spacecraft to the parking orbit. Analytical relationships for the calculation of the spacecraft design parameters have been obtained for the proposed criterion for evaluating the effectiveness of the logistic space mission and the assumption about constant thrust acceleration. The results of calculation of the design parameters are summarized.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):30-38
views
Assessing skills level of flying cadets
Kuatov B.Z., Kurtaev S.Z.
Abstract

The paper presents an analysis of works attempting verification of the adequacy of both simulation and simulators themselves. However, these attempts are limited to determining the fact of adequacy or inadequacy of the systems being checked, which cannot be used to identify the skills acquired when using them in accordance with the input generalized classification. The adequacy itself is a concomitant sign of inadequate use of simulators. However, since the established reference base for assessing the adequacy of simulators does not make it possible to present it in the form of the indicator of the concomitant sign of inadequacy of use of simulators, the task of prime importance is to determine its quantitative form that would make it possible to eliminate the disparity of proficiency assessing. A system of assessing flying cadets’ skills level is proposed in the paper. Some propositions concerning the assessment of probabilistic levels of cadets’ proficiency are discussed. A five-mark grading system with pluses and minuses (12-mark system) for assessing the level of flying cadets’ proficiency is proposed in the paper. The system allows increasing the accuracy of flight skills identifying.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):39-44
views
Identification of scale factor of a pendulum compensating accelerometer during an orbital spacecraft mission
Fominov I.V.
Abstract

The paper deals with a crucial task of estimating the metrological characteristics of a pendulum accelerometer which change under the influence of perturbations in the flight of spacecraft. A method is developed that makes it possible to estimate the value of the scale factor of a compensating pendulum accelerometer in the system of spacecraft maneuver control through the use of grapho-analytical and indirect methods of diagnosing first and second order systems. The proposed method makes possible automatic identification of the scale factor in the absence of external forces of non-gravitational origin. The essence of the method is based on the signal-extracting impact on the actuator accelerometer which causes a natural deviation of the sensing element, and the analysis of the transient response of the accelerometer output signal. Numerical studies show that the accuracy of estimating the scale factor in accordance with the proposed method depends on three factors: the output of the measuring noise, the attenuation coefficient of the pendulum accelerometer sensor, and the moments of the external forces acting on the sensitive axis of the accelerometer in the identification process. The results of simulation led to the conclusion about the possibility of applying this method in solving the problem of self-control of the characteristics of a pendulum accelerometer. It is shown that an increase in the accuracy of estimating the scale factor is possible due to the use of statistical methods of smoothing and filtering. Preliminary analysis showed that the proposed method can be implemented in the creation of algorithmic software of the self-control system of smart accelerometers.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):45-51
views
MECHANICAL ENGINEERING AND POWER ENGINEERING
“Squirrel cage” flexibility in supports of aviation gas turbine engine rotors
Degtiarev S.A., Leontiev M.K., Popov V.V.
Abstract

Elastic damper supports composed of elastic elements of “the squirrel cage” type are widely applicable in the design of aviation gas turbine engines. They are used for engine frequency detuning from unwanted resonance frequencies and for unloading of hydrodynamic dampers from the rotor weight. “Squirrel cage” elements are designed in different ways but the schemes with straight, compound and curvilinear rods are the most frequently used ones. Total flexibility of the rods that form “the squirrel cage” mainly determines the flexibility of the whole elastic-damper support in general. References [1] and [2] give simple equations to obtain radial stiffness coefficient of the elastic part of “the squirrel cage” with straight rods of the rectangular cross-section. However, “the squirrel cage” transmits not only radial forces but axial ones and moments as well. This fact necessitates consideration of other coefficients of the general flexibility matrix of “the squirrel cage”. The present article presents a methodology of determining the flexibility matrix of an elastic bush of “the squirrel cage”. The given methodology is applicable for bushes with straight rods (finite-element methods should be used for compound and curvilinear rods). Flexibility matrix components are obtained using the methods of strength of materials. The elastic bush of “the squirrel cage” is considered as a set of straight short rods restricted by stiff flanges from the butts. As a result, an analytical equation depending on the bush characteristics was obtained for every matrix component. As a test example, a flexibility matrix for the defined characteristics was obtained. Meanwhile, the time of obtaining the flexibility matrix does not exceed fractions of a second. Similarly, a flexibility matrix was obtained using calculations in the finite-element complex. The difference between the results obtained was less than 1%. The given algorithm and the flexibility matrix obtained with its help may be used for the simulation of support units of aviation gas turbine engines in rotor dynamics tasks.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):52-60
views
Regenerative air-water heat exchanger with improved heat exchange ability
Dostovalova S.S., Serebryakov R.A., Batukhtin S.G., Batukhtin A.G.
Abstract

The article describes a power-efficient scheme for using solar energy in centralized heat supply systems that makes it possible to reduce capital and operating costs and increase the degree of substitution of traditional sources of heat. The versatility of systems based on the scheme determines a wide range of their applications: from cottage- type houses to the heating of industrial facilities and greenhouses. The essence of the proposed scheme is that the solar collector for heating medium is switched to the air duct connected to the heated space and an antifreeze substance which circulates in the circuit: storage tank - solar collector. A method of intensifying heat transfer through the use of hole-type intensifiers is proposed. The intensification efficiency is determined by the calculation of daily heat absorption of a flat air collector with the intensification by using holes and without these, the economic effect of the introduction of the proposed method is also determined. According to the calculations, the proposed heating scheme and the intensification of heat transfer on the surface of the collector included in it can provide tangible economic benefits in the implementation.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):61-66
views
Check and prediction of gas-turbine engine’s technical state
Zotin N.A.
Abstract

The problem of check and prediction of a gas-turbine engine’s technical state is presented in verbal and mathematical statements in the paper. The mathematical statement of the problem is presented as a ternary system. This system consists of three components: initial data for solving the problem; a set of conditions and restrictions to be accomplished in the process of solving the problem; the required result to be obtained by solving the problem. The initial data for solving the problem consist of a set of propulsion unit parameters and environment parameters registered at different time moments as well as sets of expert reports on the technical state of gas-turbine engines. Among the limitations imposed when solving the problem we can name a fixed list of the registered parameters of the power plant as well as the absence of the possibility of purposefully extending the base of empirical data. The required result to be obtained by solving the problem includes: a model for determining check, diagnostic and prognostic parameters; the function of calculating the criteria of the technical state; the function of extrapolating the above-mentioned criteria; a set of control, diagnostic and prognostic criteria. Each component is described in the paper using the semantics of sets and multisets.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):67-73
views
Post-operation state and extension of service life of compressor blades of the gas-turbine power plant GTE-45-3
Tarasenko Y.P., Berdnik O.B., Tsareva I.N.
Abstract

Gas turbine engine compressor blades are the most essential parts among all the units of gas turbine power plants. They are made of chromium stainless steels. Erosive and corrosive wear of working surfaces as well as thermal stress fatigue are the main types of damage of compressor blades after long-term use.  The aim of this work was to develop methods of recovering the serviceability of the material of the power plant ГТЭ-45-3 compressor blades with a view to extending their service life. To examine the post-operation state of compressor blades and the material serviceability the compressor blades of the gas turbine engine power plant ГТЭ-45-3 made of corrosion-resistant steels ЭИ961 (13Х11Н2В2МФ) and 12Х13 were investigated after their service life expired with the total engine hours equal to 50000. To evaluate the serviceability of the blade material an unconventional approach and know-how were used. The results of analysis of the microstructure of corrosion-resistant steels as well as their physical and mechanical properties are presented in the paper. A process of material serviceability recovery is developed with a view to extending the service life of compressor blades. The process includes the following sequence of operations: machining aimed at removing corrosion and mechanical defects, argon-arc welding that  restores the geometry of the rotor blades, thermal tempering for removing residual stress.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):74-81
views
Structural and acoustic anisotropy of turbocompressor blade material
Tarasenko Y.P., Krivina L.A., Motova E.A., Nikitina N.Y.
Abstract

The investigation is concerned with working compressor blades of the sixth and eighth stages of the turbo-compressor rotor of the ДЖ59Л engine made of stainless ЭИ961 (13Х12Н2В2МФ) heat-resistant steel in a post-operation state and the same blades after tempering. The objects of research are the parameter of intrinsic acoustic anisotropy and the structural anisotropy factor of the carbide phase of material of turbo-compressor blades in post-operation state and subsequent tempering. The aim of the study is to show that the ultrasonic echo technique holds promise as a method of nondestructive control of the material structure directly on the product both at the stage of output control in the production and repair of blades, and in the post-operation state. The analysis of the blade material structure is carried out using the methods of optical metallography with the use of the “GoodGrains” software and ultrasonic echo technique of nondestructive control. Using the method of optical metallography it was established that a carbide phase of acicular shape is present in the material of blade airfoil with a high degree of anisotropy, which indicates the degradation of microstructure in the post-operation state. Positive influence of tempering on the uniformity of carbide phase distribution in the material of rotor blades is noted. Correlation between the parameter of acoustic anisotropy and the metallographic anisotropy factor of inclusions of a carbide phase in the blade material is revealed. The echo technique of nondestructive control of structure shows great promise for application at any stage of output control directly on a product.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):82-89
views
Heat-shielding zirconium dioxide coating on an intermetallic substrate obtained by the method of high-energy plasma spraying for gas-turbine engine turbine blades
Tarasenko Y.P., Tsareva I.N., Berdnik O.B., Fel Y.A., Fedorchenko D.G.
Abstract

The paper discusses the task of protecting the working surface of turbine blade made of heat-resistant nickel alloys against high-temperature gas corrosion and high temperature gradient. Improvement of the performance characteristics of a heat-shielding coating is achieved by increasing the energy characteristics of the plasma spraying process (temperature of the plasma flow, mass-average velocity of the plasma jet) with the help of up-to-date ЖС6Ф equipment using a ПНК-50 plasma torch. Special attention is given to the study of high-temperature stability of the alloy as the process of high-energy plasma spraying is associated with the heating of the substrate. The patterns of forming the phase composition and microstructure of the zirconium dioxide coating formed on the intermetallic substrate of the “Ni-Co-Cr-Al-Y” system, sprayed using the ПНК20Х20Ю13 powder mixture with particles of various dispersion are analyzed. The results of research of the structures, physical and mechanical properties as well as the efficiency of a zirconium dioxide heat-shielding coating, formed by high-energy plasma spraying and designed to provide thermal protection of turbine blades of gas turbine engines are presented. The results of the investigation showed that the coatings developed are designed to protect various-application gas turbine blades against the starting load high-temperature gradient, gas corrosion and erosive wear.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):90-98
views
Mathematic simulation of AL-31F powerplant radiation in the IR range
Filippov G.S.
Abstract

The paper is devoted to the modeling of aircraft power plant radiation. The object of investigation is the AL-31F aircraft afterburning turbojet bypass engine. The results of research dealing with the calculation of spatial distribution of radiation from complex radiators are presented. A complex method of calculating the infrared radiation based on mathematic simulation of radiant energy spatial distribution is proposed. An algorithm using the probabilistic Monte Carlo method is developed, which makes the modeled process of the beam emission and reflection similar to the physical one. A new method of calculating the indicator function in an absorbing medium from complex radiators is used. Calculations of temperature distribution inside the nozzle and modeling of the power plant geometry are performed. Spatial distribution of infrared radiation is determined on the basis of the computations made. A device for reducing the intensity of radiation over a wide angle range is developed, the analysis of its efficiency is carried out. The device proposed makes it possible to reduce the design level of infrared radiation by more than 90% in the range of the solid angle of the rear hemisphere. The results of calculating the direct (without reflections of radiation inside the nozzle) and complete (including reflections) radiation from the central ellipsoidal body are presented. The results of the comparison of these calculations are also presented.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):99-106
views
Elimination of gas dynamic resonance modes of vibration loads of gas distribution station pipeline fitting
Shabanov K.U., Kryuchkov A.N., Ermilov M.A., Balyaba M.V.
Abstract

The article contains a study of the modes of resonance interaction of a high-speed gas flow exiting from the metering sections of pressure regulators with their elements. It is shown that the interaction leads to a significant increase of the valve noise due to the tone component of the spectrum of vibration energy which occurs at the frequency characteristics of pressure fluctuations in the pipeline, the vibration of the controller output flange, as well as the external valve noise. The results of analyzing the prerequisites for resonant interaction of the gas flow with the regulator structural elements including the pylons of the central fairing are presented in the paper. It is shown that an increase in the output flow rate above a certain value (about 40 m / s) gives rise to discrete components of the spectrum of pressure fluctuations. The results of experimental analysis of the pressure regulator elements showing practical coincidence of the frequencies of discrete components of the flow pulsation spectrum and free oscillations of construction elements are also presented. Modal analysis of the natural oscillations of regulator elements is performed by tapping. Measures to remove resonant interaction of the output flow with the pylons that consist in installing special flow-splitting structures - perforated cylindrical sleeves are proposed. Other measures to eliminate the resonant interaction under consideration are also possible.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):107-118
views
CONTROL, COMPUTER SCIENCE AND INFORMATION SCIENCE
Rearrangement of digital control algorithms with variable discrete pitch size
Belonogov V.D.
Abstract

The necessity to change the control task discreteness period  can arise in the course of operation when performing a multidimensional set of tasks of digital control, filtration and control on processors having limited computing power. This can be caused, for example, by a necessity to solve more important tasks occupying the computing resources at certain moments. In this case control tasks will be solved within an increased discreteness period , which will lead to the deterioration of the system dynamics at constant parameters of the digital regulator, and even to the loss in stability of a closed digital system, which is possible with a sufficient change of the period. A rearrangement of regulator parameters (operational conversion) versus the  parameter determining the rate of quantization period change is needed to recover the circuit dynamic properties. This algorithm rearrangement should be implemented automatically in the process of digital system functioning and, consequently, the rearrangement algorithms should take a fairly simple form. The present work is concerned with the rearrangement of digital control algorithms in case of a significant change in the discreteness period of the control task. The criteria of the proximity of digital regulator characteristics are given for the changed and initial discrete pitch size . Explicit formulae of digital regulator constant conversion are obtained for the simplest control laws based on the criteria presented and a methodology of control constants rearrangement is formed for the general case.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):119-128
views
Adaptive biofeedback in the restoration of movements in patients with traumatic disease of the spinal cord
Bogdanova L.P.
Abstract

The aim of this work was to develop a method of adaptive biofeedback using visual and auditory feedback to repair movement disorder in patients with traumatic disease of the spinal cord in case of complex spine fracture on the basis of data on the changes in electrophysiological properties of muscles and spinal motor neurons involved in the pathological process. Sixty four patients were treated and tested in the first month after injury, 40 of them male and 24 female. Depending on the application of techniques used for the treatment all patients were divided into two groups representative by gender, age, the extent of the damage and the severity of the condition group. Forty patients of the main group were treated by a new complex of medical rehabilitation. The experimental group consisted of 24 patients whose treatment was performed by a conventional method. For comparison, we studied the electrophysiological characteristics of muscles in 120 healthy people. A method of adaptive biofeedback based on increasing visual and auditory monitoring of muscle contraction involved in the pathological process was developed to restore patients’ ability of movement. The method is based on the registration, strengthening and transformation of bioelectric activity of the muscles involved in the pathological process into light and sound signals that the patient can see on the screen of the electromyograph. After the treatment using the method of adaptive biofeedback and therapeutic exercises 85,5 % of the patients developed the possibility of active muscle contraction, whereas  no improvement of the recovery process was  observed in the experimental group of patients.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):129-137
views
Stimulation electromyography in determining the mechanism of therapeutic action of adaptive feedback for patients with traumatic disease of the spinal cord
Bogdanova L.P.
Abstract

The aim of this work was to study the mechanism of the therapeutic action of the adaptive biofeedback method using visual and auditory feedback to repair movement disorder in patients with traumatic disease of the spinal cord in case of complex spine fracture on the basis of data on the changes in electrophysiological properties of muscles and spinal motor neurons involved in the pathological process. Sixty four patients were treated and tested in the first month after injury, 40 of them male and 24 female. The age of the patients ranged from 19 to 40 years, the average age being 28,3 years. All the patients were subjected to a complete orthopedic and traumatological, neurological, laboratory, radiographic and electrocardiographic examination. Electroencephalography was also carried out if required on therapeutic grounds. After adaptive biofeedback an increase in total excitability of the patients’ spinal motor neurons by a factor of 2,2 was noted. The involvement of alpha-BMN increased by a factor of 2,5 and that of alpha TNM increased by a factor of 1.6 approaching the performance of healthy people. The sensitivity of primary muscle endings increased by 64,5%. The degree of attenuation of the re-induced spinal reflex practically did not change.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):138-143
views
ECONOMICS AND HUMANITIES
The credit banking system of Samara region in the 1920s
Bannikova N.F., Samuilovа M.O.
Abstract

The article reviews the changes undergone by the bank crediting system in the USSR in the 1920s as exemplified by the activities of the Samara city municipal bank. The main goals of economic development and, primarily, currency circulation under a new economic policy of the Soviet government are emphasized. Attention is focused on the state of the economic system of the region and changes in the functions of the municipal bank in the areas of industry, agriculture, wholesale trade and transport. The relationships between the Central bank of public utilities and residential housing, on the one hand, and regional banks, on the other, as well as the role of the Samara city municipal bank in developing residential housing and public utilities in the region are shown. Special attention is paid to the solution of the problem of assisting housing construction for workers. The right of municipal banks to issue bonded loans is discussed, changes in the operating of regional banks in the late 1920s are determined. The article covers the processes of reorganization of the financial credit system related to the strengthening of economic management centralization and formation of planned economy. Attention is paid to the peculiarities of the activities of Samara city municipal bank after implementing the administrative-territorial reform. The article includes statistical data on the results of the Samara city municipal bank’s activities during the period under investigation.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(4):144-154
views

This website uses cookies

You consent to our cookies if you continue to use our website.

About Cookies