Vol 21, No 3 (2022)

Full Issue


Procedure of assessing the error of the device for measuring mass-centering and inertial characteristics of nanosatellites using reference objects

Vasin P.V., Barinova E.V.


In this paper, we solve the problem of experimental determination of the accuracy of a device for measuring mass-centering and inertial characteristics of nanosatellites which was developed at Samara University and based on the principle of inverted torsional pendulum. A procedure for determining the measurement error of the inertia tensor components and the center-of-mass coordinates using reference objects is proposed. For this purpose, a reference composite object of variable configuration was developed and produced in the form of a CubeSat 3U nanosatellite. With the help of this standard, a modified method of conducting an experiment was developed, which allows reducing the influence of errors in the manufacture of the device and its tooling on the measurement accuracy by averaging the homogeneous quantities. The article presents the results of a series of experiments to determine the errors in measuring mass-centering and inertial characteristics of a reference composite object of three variants of assembly. This series of experiments confirmed the measurement error theoretically calculated and stated in the technical documentation for the device. In addition, the accuracy of the electronic optical sensor installed on the device was evaluated and it was found that the influence of environmental factors on its operation is insignificant and can be neglected. The results of this work can be used to determine the error of measuring the center-of-mass coordinates and the inertia tensor components of a CubeSat 1U-3U nanosatellite at the pre-launch testing stage.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):7-22
pages 7-22 views

Determination of the optimal parameters and engine layout for a strike unmanned aerial vehicle

Zinenkov Y.V., Lukovnikov A.V., Agaverdyev S.V.


The article describes the solution of a complex problem to determine the optimal parameters and engine layout for the power plant of an advanced unmanned aerial vehicle according to the methodology developed by the authors using the author’s complex mathematical model and the well-known method of indirect statistical optimization based on self-organization. At the same time, the main aerodynamic and flight performance characteristics of the unmanned aerial vehicle under study, calculated according to engineering methods, are shown, as well as the parameters and characteristics of its power plant, calculated using the author’s algorithm implemented in a complex mathematical model. The results of parametric studies are also presented using the example of assessing the influence of the bypass ratio on the characteristics of a power plant and the parameters of the unmanned aerial vehicle under study. The process of conducting optimization studies of the “Unmanned aerial vehicle – power plant” system with a bypass turbojet engine with mixing of the circuit flows behind the turbine is described. At the same time, special attention is paid to the formulation of the optimization problem, the choice of criteria and changeable variables, as well as the analysis of the results obtained by comparing the efficiency of the system under study with different engine configurations according to the criteria of the aircraft level: maximum range according to two formed flight programs.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):23-35
pages 23-35 views

Two-channel optimal discrete law of control of spacecraft with aerodynamic and inertial asymmetry during descent in Mars atmosphere

Lyubimov V.V., Bakry I.


At present, spacecraft attitude stability is of great importance for both state and private space companies and agencies. In this paper, we consider a mathematical model describing perturbed motion of spacecraft as a rigid body with significant aerodynamic and inertial asymmetry relative to the center of mass in the rarefied atmosphere of Mars. The aim of this work is to obtain an approximate discrete optimized law of controlling the spacecraft attitude using Bellman's dynamic programming and averaging methods. Discrete systems of equations used in the work were solved using the Z-transform method. The reliability of the obtained control laws was confirmed by the results of numerical integration by the numerical Euler method.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):36-46
pages 36-46 views

Gas-dynamic losses in the flow part of the channel charge of a solid-propellant rocket engine

A. N. Sabirzyanov A.N., Khamatnurova C.B., Kuzmin V.V.


Modern methods of computational fluid dynamics have been used to study flows with mass supply in axisymmetric channels of solid-propellant rocket motor charges. The studies were carried out with the aim of increasing the accuracy of predicting the intraballistic parameters for performing engineering calculations. The analysis of changes in intraballistic characteristics in the flow part of the channel charge in the classical and nozzleless solid propellant rocket motors is carried out for different rates of mass supply from the combustion surface. For an isobaric combustion chamber, a characteristic velocity profile is shown along a tubular charge path and a charge with sudden expansion. It is shown that for a steady cosine profile of axial velocity after sudden expansion of the channel, a length of more than three gauges is required. For a high-speed combustion chamber, a comparison of the axial velocity profile is carried out depending on the flow velocity under different conditions of mass supply. The tendency of the influence of flow velocity on the character of the profile is noted. It is shown that at a Mach number over 0.5, an increase in the mass flow rate from the combustion surface provides a less filled velocity profile tending to cosine. The differences between the pressure losses in the flow passage of the channel charge, calculated in the axisymmetric approximation, and the losses determined using gas-dynamic functions, are shown. An increase of the mass flow rate in the charge channel of a nozzleless solid-propellant rocket motor leads to a decrease in pressure losses at Mach number over 0.8.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):47-57
pages 47-57 views

Kinetic model and kerosene surrogate for calculating gas turbine engine emission of carcinogenic hydrocarbons

Semenikhin A.S., Idrisov D.V., Chechet I.V., Matveev S.G., Lukachev S.V.


To calculate the emission of carcinogenic polycyclic aromatic hydrocarbons by the combustion chambers of aircraft gas turbine engines, the A17 kinetic model has been developed, characterized by new blocks of elementary chemical reactions of hydrocarbon compounds oxidation and synthesis of polycyclic aromatic hydrocarbons. The results of model validation showed satisfactory agreement with the experimental data and the possibility of applying the model to describe combustion processes in gas turbine engine combustion chambers. A review and numerical study was carried out for 14 surrogates (model fuels) of aviation kerosene, the combustion of which can be described using the A17 model. Simulation of stabilized flame of a previously prepared mixture showed the effectiveness of Drexel, Liu, su4, UM1 surrogates, the predictions for which agree satisfactorily with the experimental data and provide the expected levels of concentration of polycyclic aromatic hydrocarbons. The calculations show the dependence of the concentration of the most carcinogenic polycyclic aromatic hydrocarbon – benzo(a)pyrene, and the ratio of the main combustion products CO2/H2O on the molar mass of the fuel. For the experimentally determined value of the molar mass of kerosene TS-1, the smallest deviation (up to 0.25%) is demonstrated by the su4 and UM1 surrogates. Due to the best predictive capability for the ignition delay time, normal flame propagation speed, pyrolysis and combustion products, the su4 and UM1 surrogates can be chosen to calculate the emission of carcinogenic polycyclic aromatic hydrocarbons  from aircraft gas turbine engine combustion chambers.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):58-68
pages 58-68 views

Formation of a rotating ring-shaped three-body tethered nanosatellite system with limited control

Chen S., Zabolotnov Y.M.


The problem of forming a rotating ring-shaped tethered system consisting of three nanosatellites is considered. To analyze the dynamics of the tether system, a mathematical model is developed in the orbital coordinate system using the Lagrange method. Using the sliding mode control method, two control programs for the deployment of tethers are proposed, in which tether tensions and thrust forces created by low-thrust engines are used as controls. In the first control program, the control actions are directly limited by the permissible limits of tether tensions forces and thrust forces, and when designing the second control program, an auxiliary dynamic system is added into the control system, which introduces control corrections that take into account the saturation effect. The stability of motion of the tethered formation system for both control programs is investigated using the Lyapunov theory. The results of numerical simulations confirmed the possibility of using the proposed control programs for the formation of a rotating triangular tethered system in the form of a regular triangle in the presence of disturbances and with account of the given constraints.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):69-84
pages 69-84 views


Application of acoustic emission and scleroscopy for the analysis of carbon fiber-reinforced plastic samples with different degrees of matrix curing

Veshkin Е.A., Istyagin S.E., Kirilin S.G., Semenychev V.V.


Samples made of a 1.6 mm thick carbon fiber-reinforced plastic sheet with different curing modes were loaded in the elastic region according to the cantilever bending scheme. Acoustic emission was recorded using an oscilloscope. The microhardness characteristics were used as criteria evaluating the degree of matrix curing which was evaluated on the face surface of the samples and in its cross section at fixed distances from the face surface. Dependences of the frequency, amplitude of acoustic signals, temperature, deflection value and distance to the sample surface on the matrix microhardness were established. The studies showed that the value of matrix microhardness is a relevant criterion evaluating the influence of the mode of carbon fiber-reinforced plastic molding.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):85-95
pages 85-95 views

Mathematical modeling of the evolution of a tribosystem in the process of formation of equilibrium roughness of a frictional contact

Kolesnikov I.V., Koropets P.A., Manturov D.S., Shakhmatov Y.V.


As the science of friction developed, tribologists showed that reliable operation of friction units is determined by the wear resistance of the surface layer, its ability to adapt to changing operating conditions. In this regard, there is a need not only to create structures on the surfaces of friction units that have the properties of self-regulation and self-organization, but also to monitor changes in the characteristics of the surface layer. This article presents an innovative methodology for monitoring the life cycle of surface layers coated by vacuum ion-plasma treatment. In this paper, we propose a dynamic model based on the hypothesis that roughness is both a factor that excites mechanical vibrations and a consequence of these vibrations, whereas roughness changes as a result of wear under the influence of local dynamic forces. It is shown that a friction pair is a nonlinear system with complex feedbacks. Its stationary motion can be considered as a strange attractor. The randomness of motion in the vicinity of the limit cycle is due to the presence of a link of constant delay with rigid positive feedback in the model. As a result, there is constant reconfiguration of the amplitude and phase of the oscillations.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):96-107
pages 96-107 views

Analysis of the influence of lubricant supply conditions on the pressure distribution in squeeze-film dampers

Novikov D.K., Shliandina N.S.


One of the most common ways to reduce vibration in aircraft engines is the use of damping devices. Squeeze-film dampers are the dampers most widely used in aircraft engine designs. The efficiency of squeeze-film dampers is determined by their damping capacity which depends, among other parameters, on the static pressure of oil supply to the damper. This article proposes a method for calculating the static pressure in the feed groove of a hydrodynamic damper depending on the geometric size of the end gap and the value of the lubricant supply pressure. The parameters influencing the static pressure in the damper end gap are determined. Calculations are performed for different values of a hydrodynamic damper end gap, the number and diameter of the supply ports. All calculations presented in the article were performed for a short squeeze-film damper with end gaps and throttles. For comparison of parameters, the dynamic pressure was also calculated for a long squeeze-film damper. It was shown that the size of the end gap has the strongest impact on the pressure in the groove of a squeeze-film damper. It was also shown that the dynamic pressure in the gap may be significantly higher than the static pressure of supply, and failure of the lubricating film may result. In addition, it was also shown that the size of the damper end clearance affects the lubricant flow through the damper.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):108-115
pages 108-115 views

Dynamic tasks in models of product operability

Ragutkin A.V.


When developing models of critical mechanical engineering products, it is necessary to solve dynamic problems, taking into account changes in the dimension chains of links in the process of functioning of mechanisms. A method of calculating dynamic dimension chains as applied to solving direct and inverse problems is proposed. The solution of a direct problem is given under the condition that the stray field of the master link includes the errors of production and those related to the changes in the dimensions of the initial links under the action of operational loads. To obtain the value of the product part wear rate we propose using empirical dependences of the relation between the wear rate and formation of hydrogen in the process of interaction of materials.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):116-126
pages 116-126 views

Aspects of simulating stable low-cycle fatigue crack growth in the main parts of aircraft gas turbine engines

Ryabov A.A., Mokhov K.Y., Voronkov O.V., Kudryavtsev A.Y., Museev A.A.


The article presents theoretical basis for the industry-based approach for finite element modeling of stable crack growth in the main parts of an aviation gas turbine engine. An axial compressor disc is used as an example. Parameters of typical FE-models applied are provided. In addition, some effective practices of FE-modeling representing the novelty of this work are described: crack evolution increment under-relaxation and automation of the process of constructing a new crack front. Some simulation results are presented demonstrating implementation of the approach steps and benefits gained from the application of the listed features. Under-relaxation ensures maintaining the stability of a numerical solution for a significantly larger crack increment size. This leads to essential effort decrease as a result of reducing the total number of simulation cycles required. Automatic construction of a new crack front allows significant improvement in crack representation accuracy during the simulation process due to the greater number of points for which crack front evolution is determined.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):127-140
pages 127-140 views

Diagnostic indicators of tooth flank wear based on the analysis of tooth spectral component parameters

Sunduckov A.E.


The wear of gear tooth flanks of aircraft gas turbine engines is the most common and the most dangerous of their defects. Practice shows that vibroacoustic diagnostics is the most effective method for monitoring the technical condition of rotary machines, including gears. It has been shown that, in this case, it is difficult to use a widely applied diagnostic indicator of gear tooth flank wear as the intensity of an n-dimensional vector from a series of tooth harmonics. This is due to the need to measure vibration parameters in a wide frequency range and low intensity of higher tooth harmonics. The factors affecting the kinematic error, such as: technological factors (manufacturing and assembly defects), operational mode-related factors (speed, temperature, transmitted load), design-related factors (flexibility of gearing parts, tooth flank modification), and tooth flank wear, lead to a significant increase in the width of the tooth spectral component. This allowed us to suggest diagnostic indicators of wear based on the analysis of changes in its width. Using the example of a turboprop differential gearbox, we experimentally confirmed that the use of an auto power spectrum with filter width much smaller than the width of the tooth spectral component is ineffective in studying the defect being considered.  The parameters of the spectral component of the first tooth harmonic such as its width at the selected levels relative to the maximum value and their combinations, and the tooth harmonic intensity defined as a function of the power spectrum density are more sensitive to wear. The resulting dependences of the proposed parameters on the amount of wear have a pronounced non-linear nature. These diagnostic indicators allow several-fold reduction of the frequency range being analyzed.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2022;21(3):141-149
pages 141-149 views

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