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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 123 journals)
Showing 1 - 30 of 30 Journals sorted alphabetically
Acta Astronautica     Hybrid Journal   (Followers: 496)
Advances in Aerospace Engineering     Open Access   (Followers: 70)
Advances in Aerospace Science and Technology     Open Access   (Followers: 8)
Advances in Astronautics Science and Technology     Hybrid Journal   (Followers: 1)
Advances in Space Research     Full-text available via subscription   (Followers: 458)
Aeronautical Journal, The     Hybrid Journal   (Followers: 13)
Aerospace     Open Access   (Followers: 60)
Aerospace Medicine and Human Performance     Full-text available via subscription   (Followers: 19)
Aerospace Science and Technology     Hybrid Journal   (Followers: 430)
Aerospace Scientific Journal     Open Access   (Followers: 18)
Aerospace Systems     Hybrid Journal   (Followers: 6)
Aerospace technic and technology     Open Access   (Followers: 3)
Aerotecnica Missili & Spazio : Journal of Aerospace Science, Technologies & Systems     Hybrid Journal   (Followers: 4)
AIAA Journal     Hybrid Journal   (Followers: 1196)
Air Force Magazine     Full-text available via subscription   (Followers: 10)
Air Medical Journal     Hybrid Journal   (Followers: 8)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 264)
Annual of Navigation     Open Access   (Followers: 22)
Artificial Satellites     Open Access   (Followers: 23)
ASTRA Proceedings     Open Access   (Followers: 3)
Astrodynamics     Hybrid Journal   (Followers: 4)
Aviation     Open Access   (Followers: 17)
Aviation Advances & Maintenance     Open Access   (Followers: 5)
Aviation in Focus - Journal of Aeronautical Sciences     Open Access   (Followers: 10)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 27)
Aviation Week     Full-text available via subscription   (Followers: 438)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 34)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 30)
Chinese Journal of Aeronautics     Open Access   (Followers: 21)
Ciencia y Poder Aéreo     Open Access   (Followers: 2)
Civil Aviation High Technologies     Open Access   (Followers: 5)
Control Systems     Hybrid Journal   (Followers: 315)
Cosmic Research     Hybrid Journal   (Followers: 5)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 11)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 24)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 12)
Fatigue of Aircraft Structures     Open Access   (Followers: 15)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 12)
Gravitational and Space Research     Open Access  
Gyroscopy and Navigation     Hybrid Journal   (Followers: 260)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 279)
IEEE Journal on Miniaturization for Air and Space Systems     Hybrid Journal   (Followers: 2)
IEEE Transactions on Aerospace and Electronic Systems     Hybrid Journal   (Followers: 385)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 39)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 41)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 37)
International Journal of Aeronautical and Space Sciences     Hybrid Journal   (Followers: 2)
International Journal of Aerospace Engineering     Open Access   (Followers: 82)
International Journal of Aerospace Psychology     Hybrid Journal   (Followers: 23)
International Journal of Aerospace Sciences     Open Access   (Followers: 32)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 7)
International Journal of Aviation Management     Hybrid Journal   (Followers: 9)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 7)
International Journal of Aviation, Aeronautics, and Aerospace     Open Access   (Followers: 5)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 12)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 11)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 13)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 11)
International Journal of Space Structures     Full-text available via subscription   (Followers: 17)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 10)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 5)
International Journal of Turbo and Jet-Engines     Hybrid Journal   (Followers: 6)
Investigación Pecuaria     Open Access   (Followers: 3)
Journal of Aerodynamics     Open Access   (Followers: 18)
Journal of Aeronautical Materials     Open Access   (Followers: 9)
Journal of Aeronautics & Aerospace Engineering     Open Access   (Followers: 31)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 69)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 18)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 22)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 34)
Journal of Aerospace Technology and Management     Open Access   (Followers: 7)
Journal of Aircraft     Hybrid Journal   (Followers: 337)
Journal of Aircraft and Spacecraft Technology     Open Access   (Followers: 9)
Journal of Airline and Airport Management     Open Access   (Followers: 12)
Journal of Astrobiology & Outreach     Open Access   (Followers: 3)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 11)
Journal of Aviation/Aerospace Education & Research     Open Access   (Followers: 2)
Journal of Engineering and Technological Sciences     Open Access   (Followers: 1)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 205)
Journal of KONBiN     Open Access   (Followers: 3)
Journal of Navigation     Hybrid Journal   (Followers: 280)
Journal of Propulsion and Power     Hybrid Journal   (Followers: 615)
Journal of Space Safety Engineering     Hybrid Journal   (Followers: 8)
Journal of Space Weather and Space Climate     Open Access   (Followers: 27)
Journal of Spacecraft and Rockets     Hybrid Journal   (Followers: 773)
Journal of Spatial Science     Hybrid Journal   (Followers: 3)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 8)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 9)
Journal of the Australasian Society of Aerospace Medicine     Open Access   (Followers: 1)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 17)
Life Sciences in Space Research     Hybrid Journal   (Followers: 4)
MAD - Magazine of Aviation Development     Open Access   (Followers: 2)
Mekanika : Jurnal Teknik Mesin i     Open Access   (Followers: 1)
Microgravity Science and Technology     Hybrid Journal   (Followers: 2)
New Space     Hybrid Journal   (Followers: 6)
Nonlinear Dynamics     Hybrid Journal   (Followers: 20)
npj Microgravity     Open Access   (Followers: 3)
Open Aerospace Engineering Journal     Open Access   (Followers: 1)
Perspectives of Earth and Space Scientists i     Open Access  
Population Space and Place     Hybrid Journal   (Followers: 9)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access   (Followers: 3)
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 16)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 46)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 81)
Propulsion and Power Research     Open Access   (Followers: 68)
REACH - Reviews in Human Space Exploration     Full-text available via subscription   (Followers: 5)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 17)
RocketSTEM     Free   (Followers: 6)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 24)
Science and Education : Scientific Publication of BMSTU     Open Access   (Followers: 1)
Space and Polity     Hybrid Journal   (Followers: 4)
Space Policy     Hybrid Journal   (Followers: 29)
Space Research Today     Full-text available via subscription   (Followers: 48)
Space Safety Magazine     Free   (Followers: 51)
Space Science International     Open Access   (Followers: 202)
Space Science Reviews     Hybrid Journal   (Followers: 97)
SpaceNews     Free   (Followers: 825)
Spatial Information Research     Hybrid Journal   (Followers: 1)
Technical Soaring     Full-text available via subscription   (Followers: 1)
Transport and Aerospace Engineering     Open Access   (Followers: 1)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 9)
Unmanned Systems     Hybrid Journal   (Followers: 5)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 2)

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Journal Cover
Aerospace technic and technology
Number of Followers: 3  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1727-7337 - ISSN (Online) 2663-2217
Published by National Aerospace University Homepage  [1 journal]
  • Experimental determination of the state of textile materials of the D-5
           series 2 landing parachute system after long-term storage. Message 1.
           Actual state of strength of textile materials of the main parachute

    • Authors: Ігор Михайлович Сила
      Pages: 4 - 11
      Abstract: The subject matter of the article is a comparative analysis of indicators of strength and elasticity of textile materials of the main parachute canopy before and after long-term storage. A simplified approach proposed by N. A. Lobanov and P.O. Fomichov was used, the coefficients of degradation of the strength characteristics of the textile materials of the main parachute of the D-5 landing parachute system of series 2 after its long-term storage were experimentally determined. These coefficients are defined as the ratio of the strength characteristics of individual elements of the parachute system in the design sections after the operation or long-term storage to their initial value adopted in the design of the parachute. The goal is to obtain an array of data to assess the state of the physical and mechanical characteristics of the main parachute materials. It is known that in the process of long-term storage there is a deterioration (degradation) of the strength characteristics of the strongest elements of the frame of the parachute canopy, lines, canopy fabrics, reinforcing tapes, etc. Further operation beyond the established period while maintaining sufficient safety factors is possible only with the availability of modern data. Tasks: to develop and test a method of sampling materials, experimentally determine the characteristics of materials, choose an effective algorithm for calculating safety factors. The following methods and equipment were used. The actual value of the indicators was established by destructive strength measurements. The methodology for preparing test samples of D-5 series 2 landing parachute systems, taking point and elementary samples of textile materials of individual elements of the parachute system in design sections for laboratory research to determine mechanical characteristics (strength, elongation, and air permeability) has been improved. The tearing machine is equipped with specialized clamping devices. The batch size was 25 parachute systems. The breaking load and the relative elongation were measured for slings and braids, for fabric - along the warp and weft, a total of 1250 elementary samples. Degradation coefficients were calculated. The array of empirical data was processed by mathematical and statistical methods of the Descriptive Statistics software package from the add-in of the MS EXCEL Analysis Package. The following results were obtained. In terms of breaking load, the fabric of the main parachute canopy slightly (up to 3 percent) exceeds the standard value. The elastic characteristics of the fabric fully meet the requirements - exceeding 1 ÷ 4 percent. During storage, the slings of the main parachute lost up to 21% in strength, but at the same time retained their elastic properties - exceeding up to 3 times. The tapes have satisfactory strength characteristics (exceeding from 3 to 12 percent), in terms of elongation at break, they have lost from 15 to 25 percent. Conclusions. The novelty of the results obtained is as follows: for the first time, the strength characteristics were measured and evaluated in the design sections of the fabric, reinforcing tapes of the power frame of the canopy and lines of the main parachute of the D-5 landing parachute system of series 2 on a large sample of 25 parachutes; it is shown that the obtained data will be correct for all parachute systems produced in 1973-1974.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.01
       
  • Generalization of the Holland and Reissner model in case of axial symmetry

    • Authors: Костянтин Петрович Барахов
      Pages: 12 - 19
      Abstract: The purpose of this work is to create a mathematical model of the stress state of overlapped circular axisymmetric adhesive joints and to build an appropriate analytical solution to the problem. To solve the problem, a simplified model of the adhesive bond of two overlapped plates is proposed. The simplification is that the movement of the layers depends only on the radial coordinate and does not depend on the angular one. The model is a generalization of the classical model of the connection of Holland and Reissner in the case of axial symmetry. The stresses are considered to be evenly distributed over the thickness of the layers, and the adhesive layer works only on the shift. These simplifications allowed us to obtain an analytical solution to the studied problem. The problem of the stress state of the adhesive bond of two plates is solved, one of which is weakened by a round hole, and the other is a round plate concentric with the hole. A load is applied to the plate weakened by a round hole. The discussed area is divided into three parts: the area of bonding, as well as areas inside and outside the bonding. In the field of bonding, the problem is reduced to third- and fourth-order differential equations concerning tangent and normal stresses, respectively, the solutions of which are constructed as linear combinations of Bessel functions of the first and second genera and modified Bessel functions of the first and second genera. Using the found tangential and normal stresses, we obtain linear inhomogeneous Euler differential equations concerning longitudinal and transverse displacements. The solution of the obtained equations is also constructed using Bessel functions. Outside the area of bonding, displacements are described by the equations of bending of round plates in the absence of shear forces. Boundary conditions are met exactly. The satisfaction of marginal conditions, as well as boundary conditions, leads to a system of linear equations concerning the unknown coefficients of the obtained solutions. The model problem is solved and the numerical results are compared with the results of calculations performed by using the finite element method. It is shown that the proposed model has sufficient accuracy for engineering problems and can be used to solve problems of the design of aerospace structures.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.02
       
  • Airfoil seсtion in the near-sonic flow of gas

    • Authors: Юрий Александрович Крашаница, Дмитрий Юрьевич Жиряков
      Pages: 20 - 27
      Abstract: The subject of investigation in this article is transonic flow. This is a condition in which local speeds of sound are appears on the wing surface, even at the subsonic speed of the nonturbulent flow. As a result, at a certain speed of the incoming flow, the flow regime around the aerodynamic surface will change sharply, which in turn changes the aerodynamic characteristics. Aerodynamic surfaces of the most transport category airplane experience transonic airflow during flight. The goal of the investigation is to study aerodynamic characteristics using numerical methods. The use of numerical methods in the design of aircraft structures is used more and more often to determine the optimal parameters for given operating conditions. This contributes to obtaining a more optimal and perfect design. In this article, we carried out a numerical analysis of the aerodynamic characteristics of airfoils in the transonic flow case using the CAE system CFD ANSYS. As a result of the research, the distributions of the pressure coefficients over the profile surface were obtained. The nature of the flow is obtained, which is similar to the picture of the pressure coefficients for transonic flow in the published sources of this topic. In the area of the middle of the profile, a shock-wave is observed. As a result, the flow around the airfoil changes, which contributes to a change in aerodynamic characteristics. The behavior of the aerodynamic drag and lift coefficients depending on the speed of the Mach number is considered. Also, the position of the center of pressure was analyzed at various velocities of the nonturbulent flow. The calculation was carried out at the cruising altitude of a medium-range aircraft of 11 km. For the calculations, we used the characteristics of the air temperature, the pressure of a given height from the table of the standard atmosphere.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.03
       
  • Computational study of aerodynamic characteristics of the Mi-8 type
           heli-copter’s tail rotors on the hovering with crosswind taking into
           account main rotor interaction

    • Authors: Михайло Юрійович Кибальний, Андрій Павлович Дьомін, Сергій Олександрович Дегтяренко, Микола Іванович Москаленко
      Pages: 28 - 35
      Abstract: Under certain conditions of a helicopter flight, the main rotor can exert a rather strong effect on the tail rotor, changing its traction and power characteristics. The calculated and experimental characteristics of an isolated tail rotor under such operating conditions can differ significantly from those under conditions of interaction with the main rotor. The study of this phenomenon is an urgent task, since a change in the characteristics of the tail rotor and the conditions of its operation in the presence of the main rotor can cause a decrease in controllability margins and, as a consequence, the cause of an aircraft accident, for example, the so-called. "left rotation" of the helicopter. Since 1985, on helicopters from M. L. Mile, 42 aviation accidents occurred in units and subdivisions of the state and civil aviation of the USSR (and now Russia) due to helicopters falling into spontaneous left rotation. Over the past 10 years, 29 accidents (8 accidents and 21 accidents) have occurred for this reason. 29 helicopters were lost: 20 Mi-8, 5 Mi-24, 4 Mi-2. Experience shows that getting into an uncontrolled left rotation in almost 100% of cases ends with a collision of the helicopter with the ground and overturning it on the starboard side. The interaction of the main and tail rotor is most significantly manifested in the modes of horizontal flight with sliding at low speeds and hovering in crosswind conditions. This is due to the peculiarities of the formation of the main rotor vortex wake. In this article, the case of aerodynamic interference of the main rotor and several helicopter configurations in horizontal flight mode with the low speed with sliding (hovering in a crosswind) is considered. Using the methods of computational fluid dynamics, the degree of influence of the main rotor on the tail rotor was investigated in the described modes. The most severe operating modes of the tail rotor of each configuration have been determined. Based on the results of calculations, the most rational configuration of the tail rotor has been chosen, which has the greatest reserves of controllability under unfavorable operating conditions. The results obtained have been used in the design of a new perspective helicopter, modernization of the existing fleet, as well as improving the flight safety level.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.04
       
  • Development status of satellite two-phase thermal control systems

    • Authors: Рустем Юсуфович Турна, Артем Михайлович Годунов
      Pages: 36 - 51
      Abstract: The progress of space technology is leading to more and more energy-equipped spacecraft. The International Space Station already has the capacity of solar panels of more than 100 kW. Autonomous spacecrafts and satellites (including stationary ones) have the capacity of power units of kW, in the nearest future - more than 10 kW. Forced heat transfer using single-phase liquid coolants is still considered as the main method of thermal control on high-power spacecraft (SC). Single-phase mechanically pumped fluid loop is a fully proven means of thermal control of spacecraft with a moderate heat load. A significant disadvantage of such systems is that the coolant temperature varies significantly within the loop. The temperature difference can be reduced by increasing the coolant flow rate, but for this, it is necessary to increase the pump capacity, which inevitably leads to an increase in power consumption, pipeline diameters, and weight of the system as a whole. In the case of spacecraft with high power capacity (more than 5-10 kW) and large heat transfer distances (10 m and more), a two-phase mechanically pumped fluid loop for thermal control is more preferable in terms of weight, the accuracy of thermoregulation, power consumption (and other parameters). The use of a two-phase loop (2PMPL) as a spacecraft thermal control system allows to reduce significantly mass and power consumption for own needs in comparison with a single-phase thermal control system (TCS). The effect is achieved due to the accumulation of transferred heat in the form of latent heat of vaporization and intensification of heat exchange at boiling and condensation of coolant. The article provides a critical review of published works on 2PMPL for spacecraft with high power (more than 5...10 kW) and a large heat transfer distance (more than 10...100 meters) from 1980 up to nowadays. As a result, a list of the main problems on the way of practical implementation of two-phase loops is formed.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.05
       
  • The performance capabilities of the journal bearings as a supports of the
           fuel gear pump of the gas turbine engine

    • Authors: Олександр Віталійович Білогуб, Ігор Сергійович Романенко, Олександр Володимирович Гудошник, Сергій Олександрович Тристан
      Pages: 52 - 58
      Abstract: The paper is about the performance capability of the journal bearings as a support of the fuel gear pump for gas turbine engines (GTE). Supports of the external gear pump usually operate in semi-dry friction conditions, which reduces residual life and is one of the limiting factors. For this investigation, the serial gear pump was chosen with the following parameters: the number of teeth z = 14, module m = 3.8, gear-loading Р = 7800 N. The authors have studied options for a pump with an electrical and mechanical (from the rotor of the GTE) drive. The main criterion for studying the bearing capacity is the minimum thickness of the working layer of a fluid with low viscosity (kerosene). For modeling, a common theory is used based on solutions of differential equations of the viscous fluid hydrodynamics, which relate pressure, velocity, and viscous shear resistance. For technological reasons, the minimum allowable kerosene layer is limited to 5 μm. The conducted analysis considers the multi-lobe (2-, 3- and 4-lobe) bearings with different lobe orientations relative to the force vector. It was found that the 2-lobe bearing has the best load capacity (provides the largest layer of kerosene). According to the results of the previous investigation for further work, the 2-lobe bearing was chosen. The influence of load, setting gap, eccentricity, the specific radius of lobe curvature, shaft length on the bearing load capacity was analyzed. A rational type of bearing design was proposed based on the load capacity criterion (the minimum layer of working fluid). It was shown that the hydrodynamic 2-lobe bearing can be sufficiently effective for the supports of the gear fuel pumps of GTE. Based on the results of the investigation, 2 variants of the pumping unit designs were proposed. The first one for the pump driven by the gas turbine engine rotor with parameters z = 19, m = 3.3, gears width B = 34, shaft diameter DS = 48, and shaft length LS = 56 (P = 10.2kN). The second one for the electrically driven pump, z = 28, m = 1,8, B = 15, DS = 34, and LS = 41 (P = 3.8 kN). The minimum angular velocity for the pump variants is 470 and 1055 rad/s, respectively. According to the investigation results, it was proposed to conduct related studies of the working process in pumps and bearings.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.06
       
  • New technologies of laser processing

    • Authors: Ольга Валентинівна Афанасьєва, Наталія Олексіївна Лалазарова, Олена Георгіївна Попова
      Pages: 59 - 65
      Abstract: Subject and purpose. Currently, gas, solid-state, and fiber lasers are used to process materials in the aviation industry. For the thermal treatment of steels, gas CO2 lasers with a capacity of more than 1 kW used, which are reliable in operation but have high cost and low efficiency. There are no results on the use of low-power (up to 20 W) pulsed-mode lasers for surface hardening of steel products. The purpose of this work is to determine the modes of surface hardening of products from carbon and alloy steels using low-power solid-state pulsed YAG lasers. Methodology. For laser hardening, a 5 W solid-state YAG laser was used (diode pumping, radiation wavelength λ = 1,064 μm, pulse mode). The use of a nonlinear crystal made it possible to obtain UV radiation with λ = 0,355 μm (third harmonic). The following modes were investigated: processing with single pulses (duration 0,1...0,4 ms) and multi-pulse processing with short (30...70 ms) pulses. The scanning speed was 8...2 mm/s. The energy in the pulse was determined by the photoelectric method. Thermal hardening was performed on the following steels: У12, P6M5. The possibility of UV radiation hardening was evaluated on steel 20, 45, У12, and ШХ15. Findings. The optimum values of pulse duration for maximum hardness in laser hardening of the investigated steels. With multi-pulse treatment of steels, the pulse duration is shorter than with single-pulse treatment, the hardening intensity is higher, and the quality of the processed surface is better. Single-pulse and multi-pulse processing are accompanied by partial melting of the surface of steel products, which does not allow it to be used in cases where a high quality of the surface is required. Laser hardening of steel by ultraviolet radiation is not accompanied by melting. Conclusion. For surface hardening of products, where partial melting of the surface is possible, low-power lasers in pulse mode can be used. Laser hardening by ultraviolet radiation is a promising direction for thermal hardening o...
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.07
       
  • Research efficiency electrochemical polishing variable section samples
           with different roughness of steel AISI 316L, manufactured by technology of
           selective laser melting

    • Authors: Сергій Вікторович Аджамський, Ганна Андріївна Кононенко, Ростислав Вячеславович Подольський, Сергій Іванович Бадюк
      Pages: 66 - 73
      Abstract: Additive manufacturing technology, also known as 3D printing, has become an increasing amount of popular lately, and the number of materials and methods that can be used is expanding. As manufacturing processes continue to improve and evolve, the demand for faster, less expensive manufacturing processes has enabled a range of Rapid Prototyping (RP) processes to be developed. Since production processes continue to evolve and grow, the demand for faster and less expensive production processes has allowed the development of a series of processes of rapid prototyping (RP). With additive manufacturing, virtually any geometry with variations in size and complexity can be produced with a high degree of accuracy. The typical microstructure of the metal after the completion of the construction process is the dispersed dendritic and cellular structures of the γ-phase within the melt baths of single tracks, because of the overlap of which a part is created layer by layer. The main problems of ensuring high-quality products using SLM technology are porosity, hot cracking, anisotropy, surface roughness, and ensuring the necessary microstructure of the synthesized material. Improvement of surface roughness, the brilliance of stainless steel surface elements after electrochemical polishing (EP) is one of the most important characteristics of the process. Samples were made using the SLM technology from austenitic steel powder AISI 316L with a controlled defect in the form of local overheating, because of which an orange variability is formed, which is formed during 3-D printing. The samples are inversely symmetrical, have an equilateral trapezoid shape with bases of 20 and 5 mm, a height of 10 mm, and a thickness of 5 mm. The main body of both samples was printed in the same modes at a power of 220 W, a speed of 1000 mm / s, and a track spacing of 0,14 mm. To form a controlled defect when printing the boundaries of the samples, the following modes were used: power 120 W, speed 1050 mm / s, and distance between tracks 0,02 mm. The samples were printed in an Alfa-280 3D printer manufactured by ALT Ukraine. Etching to reveal the microstructure of the samples was conducted using an HCl + HNO3 solution. Electropolishing was conducted in a solution of orthophosphoric acid (H3PO4) with glycerol (C3H8O3) at a current density of 3 A / cm2. Metallographic studies have shown that the configuration of the tracks in the area of increasing the cross-section of the samples is more uniform. Based on this study, schemes for distributing zones with varying degrees of track equiaxiality and structure uniformity were constructed. A more intense interaction of the reagent with the microstructure near the surface with greater roughness was found. The electropolishing of isosceles trapezoids occurred in three stages: 1) visual - optical examination with fixation, control of roughness, weight, and geometry before starting the process; 2) control of roughness and geometry after 3 min. process; 3) visual - optical examination with fixation, control of roughness, weight, and geometry after 6 min electropolishing. From the analysis of the obtained roughness data and the real volt-ampere curve, it was found that zone 2 with the largest area had an insignificant change in roughness, zone 1 and zone 3 with a decrease in the area had a more significant loss on average by 33%. Controlling the weight before and after the test showed that the samples lost approximately the same weight of about 1,5%. Based on the ratio of the results obtained, it was found that when a fixed current strength and constant power are applied, electropolishing is not effective for active uniform anodization of the surface of a simple figure with a change in the area in the section. It was found that electropolishing most intensively occurs in an area with a smaller cross-sectional area.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.08
       
  • Multiagent modeling of production logistics in the creation of high-tech
           products

    • Authors: Oleg Fedorovich, Liudmyla Lutai
      Pages: 74 - 83
      Abstract: Economic instability and stochastic behavior of the market lead to the need to develop new methods and models to reduce the life cycle of high-tech products. Therefore, the urgent task is a detailed consideration and analysis of each main stage of the life cycle of creating complex technical products. The current study develops a method for optimizing production processes. The subject of research is a production planning and management as the main stage of the life cycle. The method proposed in the publication is based on the component architecture of the created innovative high-tech product, which is obtained because of decomposition at the initial stage of design. Modern production is of distributed nature. While planning production, it is necessary to pay attention to the management and synchronization of material and other types of flows in the logistics chain of distributed production. To form a set of basic and subsidiary operations of distributed production, it is necessary to consider the logistical features, the level of decomposition of the component architecture of the created product, as well as the type of component in the production cycle. Logistics operations are conducted following the requirements for the relevant indicators, namely, the cost of the operation, quality, competitiveness, innovation, the risk of the operation. The main criterion for optimization is the duration of operations. The work uses multi-agent simulation modeling of a sequential logistics chain of production processes, as well as mathematical models and methods: system analysis, optimization using integer programming, multi-criteria optimization, and expert evaluations. The method reduces the duration of the production cycle for the manufacture of individual components of the complex architecture of high-tech products by determining the optimal set of production and ancillary logistics operations for each component, considering the requirements for key production indicators, which minimize production time of high-tech products.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.09
       
  • Conceptual foundations of the method of encoding and storing frequency
           information for reconfiguring the R-828 radio station to new radio
           channels

    • Authors: Андрій Олександрович Красноруцький, Алі Енверович Бекіров, Василь В’ячеславович Корепанов, Олександр Анатолійович Хіжнюк
      Pages: 84 - 91
      Abstract: The article describes an innovative approach to encoding and storing frequency information of the R-828 radio station, which is implemented on special equipment of the manned complex. The purpose of the article: to develop a methodology for encoding and storing frequency information according to the сascaded concept for reconfiguring the R-828 radio station to a new radio data. The technology is developed and the methodology for automatic evaluation of current and subsequent radio data according to the cascaded concept for the presence of given information content is revealed. The stages of conversion and encoding frequency radio data of the radio station's storage device using the technology of identifying key features of given information content in the system for entering new radio data are justified. A software implementation of automating the process of converting frequency radio data into a code sequence is proposed. Automation of the recalculation process, which is built in the program for working with Microsoft Office Excel spreadsheets, is justified. The implementation of the method of converting frequency radio data into a sequence code combination is proposed to be implemented using the functions IF, MOD, ROUND, AND. It is proved that to create calculations and document the information component, the Excel table processor is programmatically used, which allows, for further data analysis (if necessary), to automatically create and receive reports in the form of tables and graphs. A method for evaluating the effectiveness of the proposed technology of encoding and storing frequency information of the R-828 radio station on new radio channels is proposed, and the obtained expert results of this method are presented. An experimental assessment of the effectiveness of the developed technology is given, which allows us to assert a reduction in the labor costs for the personnel of the aviation engineering service in the aviation brigades Air Force of the Armed Forces of Ukraine to recalculate frequencies in the appropriate code combinations and to work out control sheets for changing the frequencies of radio station R-828 channels, as well as a reduction in errors of the first and second kind when performing work on changing frequency radio data, by reducing the influence of the human factor on the occurrence of errors when performing appropriate recalculations. The relevance of the problem under consideration is primarily related to the specifics of performing tasks of the aviation engineering service in the conditions of the Joint Forces Operation in the east of Ukraine, namely, an increase in the number of operations to change operating frequencies, which reduces the probability of listening to communication channels by the enemy, which in turn affects the provision an appropriate level of noise immunity and the noise immunity of radio data exchange channels.
      PubDate: 2021-04-28
      DOI: 10.32620/aktt.2021.2.10
       
 
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