Vol 24, No 1 (2025)
- Year: 2025
- Articles: 15
- URL: https://journal-vniispk.ru/2542-0453/issue/view/20777
Full Issue
AIRCRAFT AND SPACE ROCKET ENGINEERING
Evaluation of mainline aircraft center section weight efficiency
Abstract
A method for evaluating the mainline aircraft center section weight efficiency based on a mathematical model of a deformable solid body of variable density was developed. The criterion for the evaluation of structure weight efficiency is the dimensionless coefficient of the force factor assumed by V.A. Komarov. It is revealed that the maximum structural height of a theoretically optimal wing-to-fuselage connection elastic system in the horizontal plane of symmetry of the fuselage is equal to the half of the bending moment transmission length in the connection. The geometric characteristics of the wing-to-fuselage connection were obtained, allowing the realization of engineering solutions with a significant mass reduction in comparison with the constant structural height center section. The sensitivity analysis of the force factor coefficient is performed for different positions of the upper boundary of the design area.
7-18
On the possibility of determining the parameters of the ionosphere when removing a nanosatellite from orbit using an uninsulated conductive tether
Abstract
Currently, one of the ways to quickly remove spent nanosatellites from orbit is the use of non-insulated conductive tether, during the movement of which an electrodynamic braking force arises in the Earth's magnetic field, transferring the nanosatellite to the trajectory of descent into the atmosphere. In this paper, the possibility of determining the concentration of electrons in the Earth's ionosphere from the resulting current distribution in an uninsulated tether during the deceleration of a nanosatellite is analyzed. It is shown that the concentration of electrons directly affects the position of the zero potential point on the cable and, therefore, this fact can be used to solve the problem. An algorithm for determining the electron concentration by the position of the zero potential point was developed. Numerical simulation of the process of determining the electron concentration during the deceleration of a nanosatellite is carried out, taking into account the unavoidable measurement errors.
19-30
Methods and means of increasing the efficiency of the AIST-2 type spacecraft for the task of monitoring the territory of Myanmar
Abstract
An analysis of the factors influencing the target characteristics and the required characteristic velocity during an orbital maneuver to improve the target characteristics of small spacecraft is presented. The analysis was performed for the AIST-2 type small spacecraft in orbits with an altitude in the range from 350 to 700 km, taking into account the angle of deviation of the optical axis of the spacecraft. To estimate the active life of the AIST-2D spacecraft, changes in air density caused by solar activity during the spacecraft’s orbiting are taken into account. In order to ensure the active life of the AIST-2 typesmall spacecraft for more than 10 years, and taking into account the fact that the target characteristics are the most stable as soon as the spacecraft descends to a certain height, the engines are started to maneuver the spacecraft to its initial height. The required characteristic speed is obtained from the height difference of the orbit that must be re-raised to solve the task of monitoring Myanmar’s territory, and based on this value, the required fuel mass, the mass of the propulsion system and the most suitable engine type are determined.
31-44
Analysis of the possibilities for the creation of a relay system to control a multi-satellite orbital constellation
Abstract
The paper shows the relevance of a space relay system when creating multi-satellite orbital constellations of spacecraft. The parameters of an advanced space relay system for controlling a multi-satellite orbital constellation of spacecraft are studied taking into account the structure of the spacecraft technological control cycle. A space relay system in low and medium Earth orbits is proposed as a dynamic telecommunication system to provide control of a large number of spacecraft. Necessary conditions are formulated to complete the spacecraft technological control cycle with a given quality including the realization of multiple access methods. The proposed space relay system is considered as a queuing system. An example of calculating the parameters of a geostationary space relay system in the case of using multi-beam antenna system as a queuing system is given.
45-55
Method for monitoring the performance of spaceсraft payload in real time
Abstract
A method is proposed for monitoring the performance of spacecraft payload in real time. The method is based on analyzing of the equipment state and sensor readings, and detecting unlikely rare combinations of the recorded parameters as potentially dangerous for the equipment. It is noted that the method is universal, that is, it can be applied to any type of controlled parameters, regardless of the method of their registration and physical dimension. Also, the method does not require preliminary calculation of maximal values (thresholds) for the controlled nodes. Specific examples are considered based on the data obtained during the operation of spacecraft equipment and during scientific space experiments. The results obtained can be used to increase the active lifetime of spacecraft, including multi-satellite constellations and CubeSat-type devices.
56-71
Design of low-orbit small spacecraft with optical surveillance equipment and corrective electric propulsion system
Abstract
The project of a low-orbit optical remote sensing spacecraft with a corrective electric propulsion system is described. The target equipment includes optical equipment formed according to the Ritchie-Chretien scheme with an additional re-reflection mirror. The choice of the geometry of optical equipment is justified by reducing the area of the spacecraft's midsection (to reduce the drag force from the upper atmosphere of the Earth). The guideline is the possibility of creating a small spacecraft (weighing no more than 1000 kg) to obtain satellite images with high spatial resolution (the pixel projection size on the Earth is less than 30 cm). The article presents a model of limitations from the satellite's power supply system on the operating modes of an electric propulsion system and the results of an analysis to estimate the parameters of the orbit correction cycles and the mass of the working fluid reserves.
72-84
MECHANICAL ENGINEERING
Method for searching defects in gas turbine engine blades under visible light using the U-NET model
Abstract
In the production of aircraft engine parts, methods that allow detecting surface discontinuities in the material are widely used in testing operations. One of these methods is the capillary method of non-destructive testing. To solve one of the specific tasks – detection of contamination on the inspected surface, a description of the method for searching for defects on the surfaces of gas turbine engine blades under visible light is presented. The solution to the problem of searching for contamination during inspection of blade surfaces is based on image segmentation using the U-NET convolutional neural network. The results of using the trained model on blades in the production units of PJSC “UEC-Saturn” are presented.
85-93
Analysis and optimization of piston engine exhaust noise silencer using ALLBEA NOISE
Abstract
This study presents a computational method for reducing exhaust noise in a two-stroke piston engine. The exhaust system was analyzed using the ALLBEA software package, and its optimization was performed using the ALLBEA NOISE program. A comparison of the calculated engine performance with the optimized silencer and the stock exhaust system demonstrated a 17 dB reduction in sound pressure level at the exhaust outlet, with only a minor power loss (less than 3%) at the shaft speed of 5500 rpm.
94-101
Investigation of vibration modes for optically transparent components by using digital speckle interferometry and finite element method
Abstract
An experimental method for studying the natural vibration modes of the acting faces of large-sized optically-transparent components used in the imaging and interference systems in optical-electronic sets is proposed. Based on a noise-proof digital pattern speckle interferometer, an optical system was developed to provide the registration of the normal component of the vibration displacement vectors on the flat optical surface with the deposited diffusing coating. The optimal transmission of the coating was determined for recording the contrast speckle-interferograms. The vibration modes of the flat, diffusing element included in the digital speckle pattern interferometer are investigated in order to verify the results of numerical modeling of its vibrations at resonant frequencies. For natural vibration modes recorded in the range from 0 to 900 Hz, deviations between experimental and numerical results within 5…7% were found.
114-130
Numerical modeling of delamination in composite panel under low-velocity contact with hail
Abstract
A technique is proposed to simulate multiple impacts of hailstones on composite panels based on a developed model and testing of low-velocity hailstone impacts. Using Instron 3369 and BiSS, compression tests were conducted on ice samples frozen at temperatures of –40°C, –30°C, and –20°C, respectively. Compressive strength and volumetric density were determined for each group. The elastic modulus ranged from 154 to 1214 MPa. Statistical data processing methods were applied to determine the variability intervals and average values of the elastic modulus for each interval at a freezing temperature of –20°C. Studies on hail impact on composite panels have highlighted delamination as a major failure mode. Based on experimental results, linear, quadratic, and cubic dependencies of damage (number of delaminated layers) on the composite plate when subjected to a 35 mm diameter hailstone impact on the elastic modulus and velocity of the ice were computed. The maximum number of layers destructed is 16, which is 80% of the panel thickness at a velocity of 170 m/s, with the ice's elastic modulus being 1250 MPa. Impact velocity significantly affects the composite panels damage susceptibility, with the material's elastic modulus having a weaker effect. Experimental findings show a significant correlation between impact speed and damage extent, with larger hailstones causing deeper delamination.
131-142
Design features of a granular-propellant supply system and an experimental setup for analyzing bulk materials outflow
Abstract
An analysis of the design features of a system for supplying granular propellant to the rocket engine combustion chamber was carried out and requirements for this system were formulated. The closest analogue is considered – the aluminum powder supply system of a jet engine. This supply system provides a critical flow mode for the powder-gas medium, at which the processes occurring in the combustion chamber do not affect the granular propellant supply. The disadvantages of this supply system are listed, provided that it is used in a granular-propellant engine. An engine schematic diagram was developed, as well as a control unit for the propellant supply system as part of the propulsion system that fully satisfies the stated requirements. An experimental setup for the powder-gas medium (granules and gas) outflow studying was designed, the operation of the setup was described in detail and a design diagram was given, in particular, a propellant tank and a flow control unit. Some design solutions used in the experimental setup can be subsequently used in the real rocket engine design. Based on the theoretical and experimental data available in the literature, the problems solved using the developed installation are formulated: obtaining flow and velocity characteristics of the critical outflow of a powder-gas medium as a function of the pressure in front of the outlet.
102-113
Mechanical and electrical properties of ALTEK alloy electrical foil for transformer windings
Abstract
The formation of physical and mechanical properties of the aluminum alloy ALTEK (aluminum, heat-resistant, economical, abbreviated: ALTEK), belonging to the Al-Cu-Mn system with a copper concentration of 2% and manganese of 2% during annealing was studied. For this purpose, a 0.2 mm thick foil was obtained from the studied alloy using hot and then cold rolling, which was then annealed at a temperature of 300...500°C. After that, the electrical conductivity and mechanical properties of the foil were studied. The studies showed that the 2Cu2Mn alloy retains high mechanical characteristics when exposed to temperatures of 300...400°C due to heat-resistant particles of Al20Cu2Mn3 released during hot rolling. Electrical conductivity during annealing also increases significantly. The best results are achieved with the annealing mode of 400°C, 3 h: 288.7 MPa with a maximum electrical conductivity value of 29.6 MSm/m.
143-152
Creating a quasi-linear model of an elastic damper support of the gas turbine engine rotor
Abstract
In the presented work, the calculation of critical rotor speeds and determination of vibration characteristics of an advanced gas turbine engine are considered. The engine under study contains a low-pressure compressor with an elastic damper support of a new design that has non-linear characteristics of stiffness and damping coefficients. The problem of creating a model of elastic damper quasi-linear supports of gas turbine engine rotors is solved by adding a quasi-linear element to the dynamic calculation model created by the DYNAMICS A4 software system. The parameters of the element change their values depending on the rotor speed. The task of verifying the results of experimental data is investigated. The presented technique makes it possible to build a quasi-linear model of the rotor support and ensure the coincidence of calculated and experimental data.
153-163
Vibration protection system with controlled inertial damper
Abstract
As a result of applying the theory of dynamic programming to vibration protection systems as cyclic control objects, relations were obtained that, by linking the components of the system state vector and control, allow implementing the procedure of the local minimum principle to find the optimal positional control function in relation to typical quality indicators that are clearly independent of control. Examples of finding the optimal positional control function for oscillations of an active vibration protection system are given. It is shown that, in the case of harmonic oscillations, for the adopted basic model with two degrees of freedom, the necessary adjustment of the amplitude and phase is carried out by means of discrete-type control signals, which ensures the achievement of the required vibration safety indicators for the protected object according to the adopted functional criterion.
164-173
Heuristic modeling of the process of milling aviation parts with opposed end mills by synthesis of a predictive model
Abstract
The paper presents a comparative analysis of existing milling technologies. The influence of the main negative factors affecting the quality of machined surfaces is revealed. Optimal schemes for machining with opposed cutters are proposed. The modeling of milling processes with oppositely located cutters of thin-walled extended aircraft parts is carried out. The process under study is described by the appropriate physical quantities. A system of eight characteristic equations describing the modes and components of cutting forces, as well as the dynamics of the milling process, is considered. A characteristic equation in dimensionless form is obtained, linking the geometric parameters of the cutting tool, the feed rate and the rotation frequency of the cutter. After checking the synthesized mathematical model by calculation, an experimental check of the proposed model for adequacy to the real process was carried out when machining the appropriate walls of blanks of ribs and beams made of aluminum alloy, manufactured by stamping, with oppositely located end mills. The edges of wells and pockets of aircraft parts were machined in small-scale production conditions. Roughness measurements were taken using a profilograph-profilometer. Optimum values of exponents and appropriate coefficients for simplexes of the mathematical model were determined. A comparative analysis of practical indicators and simulated data of the milling process was carried out. The resulting model allows predicting the results of machining by the proposed method with an error of 10…15%.
174-184