Technical Mechanics
type: channel
description: From 1993 to 1997, the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine published an interdepartmental collection of papers entitled Tekhnicheskaya Mekhanika, which in September 1997 received the status of a scientific journal entitled Tekhnicheskaya Mekhanika (in Russian) and Tekhnichna Mekhanika (in Ukrainian). In 2017, the institute was issued a new state registration certificate for the journal, in accordance with which the journal has the official English title of Technical Mechanics, may publish papers in English, and is entitled to international distribution. The journal publishes review and research articles on the following topics: 1.Applied Mechanics 2. Applied Mathematics 3. Aviation and Space Engineering 4. Automation and Computer-Integrated Technologies 5. Physics and Astronomy
publisher: текст 3
language: en-US
publication name: Technical Mechanics
items: TWO-CRITERIA OPTIMIZATION OF SEQUENTIAL ROUTES OF MULTI-TARGET LOW-ORBIT SERVICE AND SPACE DEBRIS REMOVAL MISSIONS
items: MICROWAVE METHODS OF EARTH REMOTE SENSING AND THE PROSPECTS FOR THEIR USE
items: RESONANCE PARAMETRIC VIBRATIONS OF A CYLINDRICAL SANDWICH SHELL
items: METHOD FOR PROJECT RANKING BY QUANTITATIVE AND QUALITATIVE CRITERIA
items: ESTIMATION OF THE DEORBIT TIME OF SPACECRAFT AND SPACE DEBRIS FROM LEO
items: VELOCITY INTEGRAL BRACKETS FOR A ONE-COMPONENT SYSTEM WITH SMALL INTERACTION
items: FEATURES OF THE STRENGTH ANALYSIS OF BOLTED CONNECTIONS BETWEEN LAUNCH VEHICLE COMPARTMENTS
items: MATHEMATICAL SIMULATION OF AN UNSTEADY LIQUID FLOW IN TANKS AS APPLIED TO THE PROBLEM OF DESCRIPTION OF LIQUID-PROPELLANT ROCKET POGO OSCILLATIONS
items: EFFECT OF THE DISTANT POSITION OF A PROPELLANT VALVE ON THE STARTUP DELAY OF A “GREEN”-PROPELLANT THRUSTER
items: ASSESSMENT OF THE PARAMETER VARIATION OF AN ELECTRODYNAMIC SPACE TETHER SYSTEM UNDER THERMAL ACTION

TWO-CRITERIA OPTIMIZATION OF SEQUENTIAL ROUTES OF MULTI-TARGET LOW-ORBIT SERVICE AND SPACE DEBRIS REMOVAL MISSIONS
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.087 In order to ensure the sustainability of the space ecosystem, new types of missions are being developed, such as on-orbit servicing missions (OOS) and active debris removal (ADR) missions. The use of OOS and ADR in low-Earth orbits has a great potential. However, their implementation faces significant problems. Only a few successful OOS missions have been launched and operated in recent decades, while ADR missions have not yet been implemented in orbit. Therefore, the study of the problems associated with the justification and preplanning of OOS and ADR missions is important to improving our understanding of these operations and their effectiveness. The implementation of OOS and ADR is closely related to the efficiency of performing a sequence of orbital maneuvering tasks under conditions of limited energy capabilities of the servicer. The values of the efficiency indices for different OOS and ABC routes may differ significantly. Methods for optimizing the routes of multi-purpose OOS and ADR missions have already been developed and are being developed. The existing literature is mainly focused on finding solutions aimed at minimizing the energy consumption of OOS and ADR missions and reducing their total duration because these factors are considered the most significant in mission planning. Much less attention is paid to optimizing OOS and ADR routes based on the flight safety criterion, which significantly affects the cost of mission insurance. This calls for the development of prompt methods for the multicriteria optimization of OOS and ADR routes taking into account the flight safety criterion. The goal of this work is to develop a prompt method for the two-criteria optimization of sequential routes for multi-purpose OOS and ADR missions performed by a servicer with propulsion units of low constant thrust. The problem is formulated as a two-criteria orbital traveling salesman problem. The methods of solving the problem…
creator: YU. M. HOLDSHTEIN
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 87
ending page: 97

MICROWAVE METHODS OF EARTH REMOTE SENSING AND THE PROSPECTS FOR THEIR USE
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.098 Microwave remote sensing (RS) allows one to obtain information at any time of day, regardless of solar illumination and in a wide range of meteorological conditions, which gives it an advantage over Earth RS methods using the optical and thermal ranges of electromagnetic radiation. At the same time, the potentialities of microwave methods are not fully utilized in commercial RS spacecraft. This paper analyzes trends in the development of microwave RS aimed at identifying the prospects for the use of these methods in commercial RS satellite constellations. Microwave radiometry, altimetry, scatterometry, and radar imaging are considered. It is shown that, due to government contracts, microwave radiometers will be massively used onboard U.S. small commercial weather satellites in the next few years. On-orbit testing of hyperspectral microwave radiometers, which are also of interest for national security and defense applications, may be expected in the coming years. The use of radar altimeters and scatterometers onboard small satellites is currently technically possible, but not in demand. These instruments are designed primarily for monitoring the ocean surface. The onboard use of altimeters and scatterometers may be caused by the needs of military meteorology and the need to improve the quality of weather forecasts in maritime theaters of war. The most actively developing line of microwave RS is space imagery using synthetic aperture radars. In the last decade, single large-size reconnaissance radar satellites have been replaced by multi-satellite constellations of small spacecraft. Of special interest is the development of operational digital models of the Earth's surface as one of the new areas of radar data application. A transition to higher-frequency bands for imaging, which has been outlined in a number of Chinese companies, will make it possible to achieve a higher spatial resolution at a lower cost. REFERENCES 1. Kh…
creator: D. O. KHRAMOV
creator: A. I. MASLOVA
creator: O. O. PYROZHENKO
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 98
ending page: 113

RESONANCE PARAMETRIC VIBRATIONS OF A CYLINDRICAL SANDWICH SHELL
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.046 This paper considers cylindrical composite sandwich shells that consist of two thin outer layers and one thick honeycomb filler. The outer layers are made of a composite orthotropic material, for example, carbon-reinforced plastic. The honeycomb filler is made of an orthotropic plastic, for example, PLA, using additive technologies. To obtain a mathematical model of nonlinear structural vibrations, the honeycomb core is homogenized into a uniform orthotropic solid layer using a finite-element simulation in ANSYS. Parametric vibrations of the cylindrical shell under the action of a longitudinal load are considered. Each layer of the structure is described by a higher-order shear theory, which uses five generalized displacements (three displacements projections onto the axes and two rotation angles of the middle surface normal). The displacement projections are continuous at the layer interfaces. The assumed mode method is used to obtain a system of nonlinear ordinary differential equations in the generalized coordinates. The method uses the kinetic and the potential energy of the structure. The shooting technique and the parameter continuation method are used jointly to analyze nonlinear vibrations, their stability and bifurcations. The multipliers are calculated to estimate the vibration stability. The stability and bifurcations of periodic oscillations are shown in the frequency responses, which describe the structure dynamics in the principal parametric resonances. As shown by the numerical analysis, standing waves are observed in the cylindrical shell. As a result of the bifurcations, the standing waves are transformed into travelling ones, which are described by a loop in the frequency response. REFERENCES 1. Karimiasl M., Ebrahimi F., Mahesh V. Nonlinear forced vibration of smart multiscale sandwich composite doubly curved porous shell. Thin Wall. Struct. 2019. V. 143. 106152. https://doi.org/10.1016/j.tws.2019.04.04…
creator: B. V. USPENSKYI
creator: K. V. AVRAMOV
creator: S. YE. MALYSHEV
creator: I. V. BIBLIK
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 46
ending page: 62

METHOD FOR PROJECT RANKING BY QUANTITATIVE AND QUALITATIVE CRITERIA
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.063 Determining the efficiency and priority of R&D projects has always been topical and important. It has been widely considered by numerous home and foreign researchers. However, the problem of project evaluation by preference in a multidimensional space of heterogeneous criteria has not been adequately addressed yet. The main goal of this paper is to present a method of project ranking by quantitative and qualitative criteria based on a consistent criteria scaling algorithm and to demonstrate its applicability. The consistent scaling algorithm (CSA) is a variant of the familiar algorithms of joint criteria scaling. As distinct from an independent scaling algorithm (ISA), which is used in the construction of an additive integral value function (IVF) in normalized form, the CSA is used in the construction of a canonical IVF. These algorithms are based on methods of multi-attribute utility theory, which use the operation of trading off one quality index against another. The classical CSA and ISA have a resolution equal to one, but they operate with qualitative criteria alone, thus considerably narrowing their field of application. To resolve this problem, the tradeoff operation of replacement in the CSA was modified, and a special procedure was proposed for joint scaling of heterogeneous criteria. Based thereon, stage-by-stage procedures were developed to construct local value functions both for qualitative and for quantitative criteria. As a result, the following problems were solved. A method was proposed to verify the preferential independence of qualitative criteria. By modifying the CSA, the problem of incomparability of heterogeneous criteria was overcome. An additive model of a canonical IVF was constructed for heterogeneous criteria, and several methods to verify the IVF for adequacy were proposed, including a constructive verification, which allows one to formally identify inadequate models. A method was developed to …
creator: V. M. MAMCHUK
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 63
ending page: 77

ESTIMATION OF THE DEORBIT TIME OF SPACECRAFT AND SPACE DEBRIS FROM LEO
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.078 The goal of this article is to develop a procedure for estimating the deorbit time of used spacecraft and space debris from a nearly circular low-Earth orbit. The paper presents, in a convenient for practical calculations form, an equation of motion of a body along a circular orbit under the action of the atmospheric drag and a given active force. At the observation stage, available online data on the orbit altitude and a model atmospheric density allow one to approximate the ballistic coefficient of the body, which is nearly always unknown in practice. At the estimation stage, the deorbit process is calculated using the approximate ballistic coefficient found previously. The deorbit time calculation error is determined as a function of the duration of the observation and estimation stages for different atmospheric models. The proposed procedure allows one to estimate the minimum acceleration to deorbit the body in a given time. The procedure is validated by calculating the deorbit time of a spacecraft whose uncontrolled flight lasted 16 years: the error is about 10 per cent of the actual deorbit time. The proposed procedure may be used in estimating the life time of space debris objects and in planning the active deorbit of spacecraft at the end of their service life. The proposed procedure may be a basis for future development with account for other interactions between an orbiting body and the space environment. REFERENCES 1. European Space Agency. ESA Space Debris Mitigation Requirements, ESSB-ST-U-007, Issue 1. 83 pp. URL: https://technology.esa.int/upload/media/ESA-Space-Debris-Mitigation-Requirements-ESSB-ST-U-007-Issue1.pdf (Last accessed on January 23, 2025). 2. State-of-the-Art Small Spacecraft Technology. NASA Ames Research Center, Small Spacecraft Systems Virtual Institute. Moffett Field, CA 94035-1000. 416 pp. URL: https://www.nasa.gov/wp-content/uploads/2025/02/soa-2024.pdf (Last accessed on February 12, 202…
creator: D. N. LAZUCHENKOV
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 78
ending page: 86

VELOCITY INTEGRAL BRACKETS FOR A ONE-COMPONENT SYSTEM WITH SMALL INTERACTION
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.114 The standard and widely used approach to the description of the hydrodynamic stage of the system evolution is the Chapman–Enskog method, in the framework of which the system distribution function is calculated in a perturbation theory in small gradients. The system kinetic coefficients are calculated on the basis of the obtained first-order-in-gradients distribution function, the temperature and velocity parts of which are the solutions of Fredholm integral equations of the first kind. In the literature it is considered that the standard approach to the solution of the corresponding integral equations is an approximate search for their solution with the help of the Galerkin method based on an artificially truncated Sonine polynomial expansion. The so-called integral brackets are needed in order to calculate the coefficients multiplying the polynomials, and the calculation of the integral brackets is the most cumbersome stage of the kinetic coefficient calculation. In the literature it is assumed that the solution of a Fredholm equation of the first kind converges fast with increasing number of polynomials, that is why the corresponding analytical solutions are often restricted to the one- or two-polynomial approximations. However, for a number of systems the numerical investigation of the corresponding convergence is made on the basis of the corresponding numerical calculations for many-polynomial approximations. We do not know any works where the corresponding numerical investigation would be provided for a system with small interaction described by the Landau kinetic equation which contains the Landau collision integral. In our previous paper, we calculated the so-called temperature integral brackets for a one-component system with small interaction up to the thirteen-polynomial approximation; the corresponding integral brackets are needed in order to calculate the system thermal conductivity. In this paper, we calculat…
creator: V. N. GOREV
creator: V. V. TYTARENKO
creator: A. N. TURINOV
creator: T. E. VORONKO
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 114
ending page: 122

FEATURES OF THE STRENGTH ANALYSIS OF BOLTED CONNECTIONS BETWEEN LAUNCH VEHICLE COMPARTMENTS
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.003 This work is devoted to the study of the features of the deformation of bolted flange connections of launch vehicle compartments and the determination of failure loads thereon. The goal of the work is to study problematic issues of the correct choice of an analytical model for flange connections of individual compartments. A method for determining the ultimate load on a bolted connection is presented. Finite element analysis methods were used. The calculations meet all the requirements adopted in the field of bolted connection strength standards. Relevant safety factors are also used. Account is taken of bolt thread stripping, unloading sleeve shearing, the bolt tightening force simulated by the introduction of corresponding temperature loads, and other connection member parameters. The results of full-scale destructive tests of the flange connection of the end frames of individual compartments are analyzed. A discrepancy between the calculated results and the test data is found out. It is shown that the discrepancy is due to an insufficiently correct consideration of the design features of the connections and the action of external loads, which led to additional components of eccentric tension-compression. It is demonstrated that the destructive load calculated with account for the “force lever” predictably proved to be smaller than that calculated in the assumption of a rigid frame and close to the full-scale test data. The article also presents the results of a numerical finite element study of the sensitivity of calculated results to variations in the principal bult connection parameters: the bolt tightening forces, the unloading sleeve diameter, the constructive offset of the bolt axes to the middle surface of the compartment shell, etc. The results obtained may be useful as a scientific and methodological basis for the correct choice of analytical models for flange connections of launch vehicle compartments. REFEREN…
creator: V. V. HUSEV
creator: A. P. DZIUBA
creator: D. V. KLYMENKO
creator: V. M. SIRENKO
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 3
ending page: 8

MATHEMATICAL SIMULATION OF AN UNSTEADY LIQUID FLOW IN TANKS AS APPLIED TO THE PROBLEM OF DESCRIPTION OF LIQUID-PROPELLANT ROCKET POGO OSCILLATIONS
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.009 In today’s liquid-propellant launch vehicles (LVs), the propellant mass may exceed 90 % of the total LV mass. When describing longitudinal oscillations in an elastic tank, the propellant is usually simulated by mechanical oscillators. This approach ignores the difference in dynamic processes in the liquid propellant components in the tanks and in the LV structure as an elastic body. The goal of this paper is to account for the features of an unsteady tank liquid flow as applied to the problem of description of liquid-propellant rocket pogo oscillations. An approach is developed to mathematical simulation of unsteady liquid flow in liquid-propellant LV tanks as a distributed-parameter system. Using the impedance method, a nonlinear system of equations is derived to determine the effective sound speed in the tank propellant and the inertia resistance coefficient at the tank outlet. An approach is developed to mathematical simulation of an unsteady liquid flow in liquid-propellant LV tanks as a lumped-parameter system. A lumped-parameter mathematical model is constructed to describe two eigenmodes of the tank liquid oscillations. A system of equations is derived to determine the coefficients of the lumped-parameter model, which uses the effective sound speed and the inertia resistance coefficient at the tank outlet found in the distributed-parameter model. The above approaches are demonstrated by the example of the oxidizer tank of the Cyclone liquid-propellant LV’s first stage. It is shown that the effective sound speed is one seventh of the sound speed in an infinite medium. The inertia resistance coefficient at the tank outlet is far greater than the total inertia resistance coefficient of the tank liquid (early in the flight, by a factor of more than 10). These results show the tank bottom dynamics is of great importance in mathematical simulation of an unsteady tank propellant flow. The model coefficients are determined…
creator: S. I. DOLGOPOLOV
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 9
ending page: 20

EFFECT OF THE DISTANT POSITION OF A PROPELLANT VALVE ON THE STARTUP DELAY OF A “GREEN”-PROPELLANT THRUSTER
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.021 In recent years, the leading space countries have paid much attention to a search for and the application of new toxically safe propellants for spacecraft thrusters. A water solution of an ion substance, a fuel, and a stabilizer is used as a “green” propellant. Its feature is a significant increase in the temperature in the thruster reaction chamber in comparison with traditional propellants. Electrically driven propellant valves, which control fuel feed to the reaction chamber in response to thruster startup and shutdown signals, are connected to the reaction chamber via an additional propellant pipeline to provide thermal conditions required for the valve operation. This design solution is responsible for an additional delay between a command signal and a thruster startup, thus complicating the operation of the spacecraft control system. The propellant feed time must be calculated with account for a low pressure in the pipeline, which is characteristic of orbital conditions. The goal of his work is to calculate the startup delay of a “green”-propellant thruster caused by the propellant valve being at a distance from the propellant nozzles in the reaction chamber under conditions of a vacuumized pipeline. The paper considers thermophysical processes during the filling of a vacuumized pipeline between the valve outlet and the propellant nozzle and presents a mathematical model that accounts for propellant ebullition and propellant vapor extrusion through the propellant nozzle until the liquid propellant boundary reaches the reaction chamber inlet. The paper presents the liquid propellant flow rate, the vapor pressure, the temperature, and the relative volumes of the liquid and the vapor calculated as a function of time at different values of the propellant tank pressure and the pipeline-to-nozzle diameter ratio for a thruster of nominal thrust 1 N. It is shown that the effect of the propellant tank pressure and the design…
creator: Yu. V. KNYSHENKO
creator: V. I. SHCHERBAKOV
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 21
ending page: 30

ASSESSMENT OF THE PARAMETER VARIATION OF AN ELECTRODYNAMIC SPACE TETHER SYSTEM UNDER THERMAL ACTION
type: item
description: DOI: https://doi.org/10.15407/itm2025.03.031 This paper presents a refined model for determining the tether temperature variation in orbital motion, which is of importance to the operation of passive electrodynamic space tether systems (EDSTSs) with a thermoelectronic coating. It is shown that a thermoelectronic coating of a tether significantly increases the collection of currents by the system, thus considerably increasing the EDSTS operational efficiency in comparison with the absence of additional contactors. The effect of thermal conditions on the EDSTS parameters is studied. The EDSTS component temperature variation is studied using a thermal balance equation, which accounts for the direct solar heat flux, the Earth-reflected solar heat flux, the Earth’s intrinsic heat flux, the aerodynamic heating, the ohmic heating, the electron impact heating, the thermal radiation of the tether, and the tether hat conductivity. To calculate the electric currents in the EDSTS passive operation, use is made of models based on orbitally limited current models for the anode segment of the tether and the Richardson – Dushman theory for total emission from the cathode segment of the tether. It is shown that on of important issues in EDCTS designing and making is the choice of a tether material that would meet certain requirements for its characteristics. The material parameters to be accounted for are the heat capacity, the IR solar absorptance, and the IR emittance. These parameters are crucial in the calculation of the system temperature variation. The greater the heat capacity, the slower the processes of system component heating and cooling. It is shown that the extreme temperatures of the system components in the shadowed and the illuminated portion of the orbit depend significantly of the ratio of the tether IR solar absorptance to the tether IR emittance. This ratio is governed both by a specific material and by the presence of impurities therein and the roughness or mirr…
creator: O. V. MISHCHENKO
rights: Copyright (c) 2025 Technical Mechanics
date: 2025-10-28
publication date: 2025-10-28
number: 3
starting page: 31
ending page: 45