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Mathematical modeling of mechanical properties of structural steels
Статья научная
On the basis of available published data and with the aid of a personal computer found equations of the dependence of the yield strength σ 0,2, of reduction of area φ and of impact toughness a 1 of a group of a structural steels on their tensile strength σ u with correlation coefficients.
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Статья научная
In this scientific work, a method of controlling high-frequency products from polymeric composite materials is con- sidered. The authors of the work present the rationale for choosing a method of high-frequency diagnostics as the most suitable for non-destructive testing of products from polymeric materials of machine-building and rocket-space pur- poses. In the presented article, the primary task of creating and studying a mathematical model of the effect of high- frequency radiation on a polymer product, including those with a “metallic inclusion” defect, has been stated and solved. In addition, the work presents the calculations of diagnostic parameters using the mathematical model devel- oped during the study. The calculation of the dynamics of heating the product and the temperature distribution during the control process is presented. The results of the calculation of specific power are described, the dependence of the instantaneous power consumption on the warm-up time is found. In the study based on a mathematical model, the Aleo- Diagnost software package was developed and registered, which is directly intended to ensure the functioning of the diagnostic devices and the investigation of the monitoring process. In addition, the developed complex allows solving a number of such practical problems as the calculation of the operating voltage depending on the geometrical parameters of the product and the determination of the value of energy consumed for monitoring the product for a specified period of time. This stage was necessary, as the consumed energy is the main output parameter of the diagnosis. In addition, the value of energy consumed is taken as the basis for the organization of the process of non-destructive testing in the automated mode. The solution of the tasks in this work has significantly reduced the cost of preparation of diagnostic operations, as well as improve the quality of control of products on an industrial scale at the stages of manufacture, operation and during repair work. The article also presents practical results, conclusions.
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Measurement of temperature distribution using a three-wire system of sensors based on thermistors
Статья научная
Improving the reliability and increasing the avionics resource is associated with possibility of continuous control of temperature fields of printed circuit boards. This problem can be solved only with the use of a large number of temperature sensors. It raises the problem of connecting the measuring elements and recording equipment. Several methods with their own advantages and disadvantages are proposed. One of the implemented and patented methods is using a set of resistive diode sensors installed in series on a threewire line. The temperature sensors are pairs of counter - connected diodes with a sequential survey when applying sawtooth voltage. The system is simple and easy to implement, but its main drawback is the method of determining the temperature by measuring the amplitude of the total reverse currents of diode pairs. It determines the large measurement errors, especially in the temperature range less than 20°C. The article deals with a similar design of a three-wire circuit, but with a fundamentally different approach to temperature measurement. The temperature sensor here is not diode pairs, but thermistors with a well-known dependence of resistance on temperature and high accuracy, and diode pairs record only the moment of coincidence of the sawtooth voltage with the voltage on the thermistors. This approach allows using mathematical methods of signal processing to accurately determine the voltage drop on the thermistor, and this ensures the accuracy of the resistance/temperature and the expansion of the temperature range. Given the fact that thermistors are increasingly used to measure temperature, simplifying their inclusion in a large number will allow to register the temperature field of electronic units, which is extremely important for spacecraft. The proposed version of a three-wire circuit for connecting temperature sensors at several points was tested experimentally, including at negative temperatures.
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Mechanical analysis of onboard equipment and the issue of finite-element model adequacy
Статья научная
In this article we have considered issues related to the applied software package, designed to conduct onboard mechanical analysis of spacecraft equipment using FEM, together with an algorithm that simplifies the aforementioned models and estimates their correctness.
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Статья научная
One of the main tasks arising in power supply systems (PSS) of spacecraft (SC) design is the determination of ra- tional structure in terms of providing consumers with electricity of the required quality. At the same time, a reasonable consumption of power generated by solar batteries (SB) and accumulator batteries (AB) should be realized in PSS. The choice of the PSS structure is based on the calculation and comparative analysis of PSS options, taking into account the adopted system performance criteria, the main ones being the energy and weight-dimension characteristics. For this purpose, the process of energy flows distribution in the PSS by forming a mathematical description of the PSS operating modes is carried out. In order to obtain the graphs of the SB generated power and to calculate SB parameters during the service life, a mathematical model of the SB based on the use of initial and experimental parameters of its photo- voltaic elements of any area was developed. The SB model provides the required accuracy of I-V and V-W characteris- tics calculation for any given values of illumination and temperature. In the article the method for calculating the energy characteristics of PSS and SB parameters taking into account the possibility of its limitation at the maximum or minimum level was described. It is shown that the method allows to determine the ways of rational redistribution of energy flows in the systems being designed to improve its weight- dimension characteristics by reducing the maximum design power of energy-converting equipment (ECE), which is achieved by forming a rational logic for applying the SB maximum power point tracking mode, in particular, when the spacecraft leaves the Earth's shadow. Energy balance in PSS is provided by applying correction coefficients. The calcu- lation results obtained by the method are the basis for requirements for ECE and SB design in PSS and can be used by developers and manufacturers of onboard and ground PSS.
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Статья научная
Plates, beams and shells with a non-uniform and micro-uniform regular structure are widely used in aviation and rocket and space technology. In calculating the strength of elastic composite structures using the finite element method (FEM) it is important to know the error of the approximate solution for finding where you need to build a sequence of approximate solutions that is connected with the procedure of crushing discrete models. Implementation of the procedure for grinding (within the micro-pass) discrete models of composite structures (bodies) requires large computer resources, especially for discrete models with a microinhomogeneous structure. In this paper, we propose a method of equivalent strength conditions (MESC) for calculating elastic bodies static strength with inhomogeneous and microinhomogeneous regular structures, which is implemented via FEM using multigrid finite elements. The calculation of composite bodies’ strength according to MESC is limited to the calculation of elastic isotropic homogeneous bodies strength using equivalent strength conditions, which are determined based on the strength conditions set for composite bodies. The MESC is based on the following statement. For all composite bodies V 0 , which are such a homogeneous isotropic body V b and the number of p , if the safety factor nb of the body V b satisfies the equivalent conditions of strength pn 1 (1+ da ) £ nb (1-d2 ) £ pn 2 (1-da ) , the safety factor n 0 of the body V 0 meets the defined criteria for a strength n 1 £ n 0 £ n 2 , where n 1 , n 2 specified, the safety factor n 0 ( nb ) complies with the accurate (approximate) solution of elasticity theory problem is built for body V 0 (body V b ); da b , corresponding to approximate solution. When constructing equivalent strength conditions, i. e when finding the equivalence p coefficient, a system of discrete models is used, dimensions of which are smaller than the dimensions of the basic composite bodies models. The implementation of MESC requires small computer resources and does not use procedures for grinding composite discrete models. Strength calculations for bodies with a microinhomogeneous structure using MESC show its high efficiency. The main procedures for implementing the MESC are briefly described.
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Статья научная
The purpose of developing a method for detecting quality anomalies of interactive electronic technical manuals (IETM) in application to aircraft maintenance and repair is an objective, purposeful interpretation of assessment of the specified quality. This method is a combination of the corresponding logical-mathematical model of such anomalies designed for subject content logic circuits (SCLC), and the algorithm of its performance in the technological process of compiling interactive electronic manuals. The IETM model of quality anomalies provides the analysis of the SCLC structure as some basic graph and regards the anomaly as a more specific graph. The specific graph is a graphical description of various partial distortions of the logic presented in the form of SCLC. Such a representation of quality anomaly of IETM for aircraft maintenance and repair - by a graph isomorphically nested in the structure of its SCLC - allows to reduce the detection of such anomalies to the mathematico-algorithmic problem of detection or search for the corresponding isomorphic subgraph in the configuration of the corresponding logic circuit. This allows to detect persistable structural embeddings charac- terizing logical errors in the feeding of electronic content to IETM for aircraft maintenance and repair from the list / database of predetermined anomalous logic substructures. The proposed method for detecting IETM quality anomalies in application to aircraft maintenance and repair is both a methodological toolkit and an extensive basis for design of suitable software models for automatic procedures of valid structure and content correction in concrete interactive electronic technical manuals.
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Methodological aspects of analysis and forecast of economic systems' development
Статья научная
Assessment methodology of the different territories' economic effectiveness is uniform and independent of a territory's size and structure. However, certain methodological assessment techniques could differ according to the characteristics mentioned. The complex's type and special features of the problem being solved are of particular importance when choosing a research method.
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Methodological basis of project performance assessment for rocket and space industry enterprises
Статья научная
The article identifies the main problems and directions of work improvement in the field of project performance assessment at the enterprises of the rocket-space industry, both on performance and project management efficiency.
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Статья научная
This paper deals with the research methods of wing-in-ground effect vehicle (WIG vehicle) longitudinal static stability. The methods are focused on the use of the algorithm of preliminary WIG aerodynamics and control system design. The algorithm is based on the iteration process of stability criteria calculations, the subsequent factor analysis of these criteria with respect to their value-determining parameters and variations of WIG vehicle configuration parameters. The methods include preliminary determination of WIG vehicle aerodynamic characteristics. The best results can be obtained when different methods of determining these aerodynamic characteristics (experimental and by means of computational aerodynamics) are combined. In this paper the calculation of aerodynamic characteristics is performed by applying ANSYS software packet. To assess the reliability of the aerodynamic characteristics obtained with the ANSYS program, experimental studies in a wind tunnel and a vertical hydrodynamic pipe were carried out. Certain aerodynamic characteristics are determined by means of originally made computer programs using the method of discrete vortices. A special database is formed of the obtained aerodynamic characteristics. The database essentially is a mathematical model of a WIG vehicle which supplies the characteristics (aerodynamic coefficients and their derivatives) with an estimated degree of reliability within a given range of determining parameters. On the basis of the widely used criterial approach to static stability assessment of various WIG vehicle modifications, a mathematical algorithm for parameter calculation and a computer program were developed. They permit the calculation-based analysis of the factors determining stability or non-stability of a WIG vehicle. The mathematical model of WIG vehicle stability analysis is implemented in the form of a software packet based on MatLab. The results worked out by the program are in the form of data suitable for operational analysis. Using these data, one can assess the WIG vehicle static stability and determine the stability range for the given structural and configurational factors. The results of the analysis make a foundation for subsequent modifications of WIG vehicle's aerodynamic configuration or for working out requirements for automatic control and stabilizing systems' upgrade. The methods demonstrating the analysis of original load-carrying systems design are also presented. For the example analysis, an original WIG- tandem load- carrying system was chosen. The methods are applicable for the analysis of various aircraft modes' stability, for all vehicles built on aerodynamic principles of flight maintenance.
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Methodology of creating management programs for case presses used in the aviation industry
Статья научная
The article is devoted to the optimization of the technological process for the manufacture of aircraft parts by the tightening method on CNC presses (Computer numerical control). The aim of the work is to create a control program that provides the manufacturing of the details-sheaths of the required accuracy and quality according to the control program in an automated mode. The method of creating control programs proposed in the article takes into account the shortcomings of the S3F software, which is the apparatus for forming control programs for the equipment considered. The method is based on the choice of the optimal loading scheme, under which the deformation program is created, the values of the control coordinates of the press are calculated in accordance with the kinematic model of the press and, as a result, a control program is formed. The mathematical module for creating control programs includes several computational units using modern CAD/CAM/CAE programs. Calculations, analysis and visualization of the tightening process were carried out using software-computational complexes MathCAD, ANSYS, T-LEX, NX, etc. As a result, we obtain a control program that provides more accurate production of the part with a minimum amount of finishing work. The presented method of calculation of the tightening process makes it possible, on the basis of the details of the part, to determine the shape of the tightening punch, and also, if necessary, to adjust the existing tightening punch in order to ensure a more precise manufacturing of the part.
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Статья научная
The article is devoted to the problem of state support for innovative activities in the region. The authors considered the direct and indirect methods of the state support for the innovative activities at the regional level and their implemen- tation. The article identifies the background of the state innovation policy and the direction of their manifestations - social and financial. The authors conduct the assessment of innovative development of Krasnoyarsk region, the main causes of low innovative activities and underdevelopment of the innovation sector in Krasnoyarsk region and define measures of state support to enterprises and organizations of the regional state administration. The article represents the analysis of the structure of budget expenditures of Krasnoyarsk region, aimed at the state support of the innovative activity in 2016. The work emphasizes on the project implementation of children’s Technopark, implemented in the framework of the Federal target program of education development for 2016-2020 and focused on priority directions of technological development of Krasnoyarsk region, taking into account the implementation in the region of the National Technology Initiative (NTI). The authors noted that to solve the problem of qualified personnel training in Krasnoyarsk region Flagship University was created, which is the basis for technology entrepreneurs aimed at creating shots for advanced technologies. At the conclusion of the study, the authors draw attention to the deterrent factors of innovative develop- ment of enterprises in Krasnoyarsk region and concluded that to ensure the competitiveness and efficiency of the regional economy it is necessary to develop the mechanism of interaction of state regulation of innovation activities at both the regional and Federal levels.
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Статья научная
The article examines the need for a methodology to monitoring the situation in the process of updating the fixed assets of enterprises of the space industry, given the variety of forms of improvement of technical characteristics of production capacity and sources of funding. Developed methodology of accounting for and monitoring of the process of updating the fixed assets of enterprises of the space industry, allowing to evaluate the process and to obtain operational information to support management decisions in terms of updates to organize and monitoring their impact on the development of the situation. The proposed method of accounting and monitoring is a cyclical implementation procedures of the accounting process and direct the collection and processing of information about the presence of unacceptable deviations from the planned renovation of fixed assets. Reviewed the content and features of each of the stages of the methods of accounting and analysis of renovation of fixed assets, the implementation of which allows to systematically create an information base for selection and justification of managerial decisions on the issue of renovation of fixed assets. This information system will be useful for large-scale, and operational management decisions.
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Methods of agents control in multi-agent expert system
Статья научная
In the article we discuss the user models interacting with distributed network resource, where every user has a correlated agent, as well as on the methods of multi-agent expert system control.
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Methods of preparation of the experiment for investigation of universal joints on needle bearings
Статья научная
The main directions of development and improvement of performance data of universal joints needle bearings of transport technological machines are considered. The questions and tasks requiring the solution at the level of forming of new calculation procedures are specified. Modern achievements in researches of endurance failures and low-cyclic fatigue of needle bearings are considered. The main overview of the works performed in this direction is provided. The analysis of modern ideas of fatigue processes of needle bearings is given. The analysis of the current state of question on research of plastic deformation at static contact loading of needle bearings is given. Questions of forecasting of durability of needle bearings of universal joints are considered. The main questions connected with processes of forming of fatigue cracks in materials of needle bearings of universal joints in zones of power contact are considered. On the basis of the analysis of the used sources it was revealed that it is necessary to resolve the issues connected with improvement of performance data of universal joints needle bearings and questions of calculation of bearing capacity of power contact of rolling bearings and technology of receiving qualitative materials. For carrying out tests we used the test facility for universal joints allowing tests without overheat of system of braking due to cooling of working fluid and also improving operating conditions due to ensuring smoothness of regulation of braking torque. For measurement of roughness of surfaces the USB BV-7669M Profilograph profilometer was used. For measurement of hardness of surfaces of thorns of crosspiece of universal joints the HBRV-187,5 hardness gage was used. The technique of carrying out tests includes the following stages: marking of crosspieces of universal joints; measurement of roughness, hardness, geometry of crosspieces of universal joints; stage of tests; repeated measurements of roughness, hardness and geometry of crosspieces of universal joints; cutting of the studied universal joints and production of microsections for metallographic examinatons of active and passive surfaces of thorns of crosspieces of universal joints; processing of results of researches. The given technique of planning of experiments is intended for receiving experimental data of researches of universal joints at different stages of operation that will allow to estimate influences of errors of production on performance data of universal joints and to prove the reasons of formation of face and deep cracks.
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Modal filter simulation with losses
Статья научная
Protection of spacecraft on-board equipment against electromagnetic interferences is an actual problem. Much attention is paid to the susceptibility to the excitation of powerful ultra short impulses (nanosecond and subnanosecond impulses). The use of known protection devices to solve this problem is hampered by a number of conflicting require- ments. For example, low mass, high reliability, long life. In addition, ultrashort pulses are able to penetrate into various radio-electronic equipment by passing the instrument shields. Protection potential using the devices based on modal filtering is well known. To simulate these devices, rigorous electro-dynamic approach is applied, which requires high computational costs. Approximate quasi-static approach allows to significantly reduce computational costs. The quasi- static simulation was used in this paper, loss record in conductors was realized by means of exact calculation of the matrix of per-unit-length resistances through a change in the matrix of the per-unit-length coefficients of electromag- netic induction when scaling the cross section of conductors. The effect of losses on the shape and amplitude of the pulses at the output of the modal filter is shown. A comparison of simulation results with electrodynamic and quasi- static approaches taking into account losses is presented. Good consistency is obtained. Quasi-static simulation with losses took much less time than the electrodynamic simulation. Analysis of the results suggests that software-based approaches can be used for modal filter simulation.
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Modal regulators of a direct current electric drive with a pulse-width converter
Статья научная
The technique of modal regulators synthesis of instantaneous coordinates values of direct current digital electric drives with a pulse-width converter by a state space method taking into account the influence of variable pure delay in the control channel is presented.
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Model-based study of oxidation processes in a jet engine fuel liquid phase
Статья научная
The process of oxidation in hexadecane liquid phase as a conventional model of oil hydrocarbons is investigated. The oxidation product structure is defined by means of Chromatography/Mass Spectrometry.
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Modeling components of bioregenerative life support system intended for space purposes
Статья научная
We have developed a linear model for compiling and optimizing food components in a bioregenerative life-support system (BLSS) intended for space purposes in the Excel environment using OpenSolver public add-in with COIN-OR- CBC solver. The independent variables in the model are the masses of ingredients used in dishes. The objective functions of modeling are to minimize the total mass of the daily diet and maximize its antioxidant potential. The daily intakes of nutrients in the menu are limited to NASA standards. The upper and lower limits are also imposed on independent variables and the masses of dishes. We have found the content of nutrients in ingredients in open databases. The menu includes the first course, the second course, snacks, desserts, drinks, bread and water. We have presented an example of a concrete calculation of the daily menu consisting of 12 dishes: fresh-soup, chicken with rice, the roast, sausages, tofu, chickpeas, candied nuts, bread, goat milk, soy milk, cocktail and water. These dishes are prepared using 24 ingre- dients: table salt, water, wheat grains, rice, quinoa, millet, sweet potato, white potato, carrots, safflower oil, soybeans, chickpeas, lentils, cowpeas, strawberries, tomatoes, onions, garlic, chili pepper, quail, pork, tilapia, goat’s milk and sugar. The ingredients being used represent edible biomass of plants and animals that are candidates for inclusion in BLSS. Caloric content of a daily diet is assumed to be equal to 2800 kcal. It is shown that food imbalances in the esti- mated daily menu are caused by a shortage of estimated daily intake of pantothenic acid, and also by an excess of iron, phosphorus and saturated fats. Excess intake of iron and phosphorus may not be critical for the health of the users of BLSS. The minimum weight of the daily menu is 2641 g, and its antioxidant potential can reach 14 mmol Ttrolox- equivalent.
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Modeling of spectroerergetic characteristics of space objects in the optical range
Статья научная
In connection with the emergence of abnormal situations at the stage of launching space vehicles (SV) for various purposes (AngoSat-1, Telkom-3, Phobos-Grunt, etc.), the problems of timely detection of such situations and remote monitoring of the technical condition of SV are of vital importance. To assess the feasibility of solving this class of problems with the use of optronic equipment (OE), it is necessary to have a priori information on the spectroenergetic characteristics (SEC) of a SV and associated backgrounds for the projected angles and conditions of observation in the operational spectral ranges of the OE taking into account the illumination by the Sun and the Earth. Due to the adapta- bility of mathematical modeling to the high degree of variability of the above factors, this method can be considered as a rational one for obtaining dynamic SEC (signatures) of SV for observation conditions that change during an or- bital flight. The technology of SEC modeling of space objects (SO) with the use of FemRad dedicated software (DS) is pre- sented, which provides the production of SO SEC taking into account the indicatrices of the scattering of optical radia- tion from materials and coatings of the external surface of the object, the dynamics of its thermal regime and the condi- tions of illumination by the Sun and Earth during the orbital flight. The advantage of the presented technology is the compatibility of the developer’s own software solutions with the widespread application programs of finite element analysis. In particular, the known CAD and CAE tools - SolidWorks, ANSYS, Gmsh - are used to develop grid geometric 3D models of SO. The method for parametric approximation of the measured indicatrices of scattering of optical radiation from mate- rials and coatings of SO on the basis of a given model of roughness is considered. The main provisions of the DS meth- odology for calculating the heat flux of the “Earth-atmosphere” system, as well as the fluxes of reflected and scattered solar radiation falling on the SO in the range 0.2-20 µm, are presented. The results of modeling the dynamic SEC of a typical SO in the infrared (IR) range are given as an illustration of the application of the DS.
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