Том 24, № 1 (2023)

At present visualization of graph models is an inherent part of the processing of complex information about the structure of objects, systems and processes in many applications in science and technology, and at the market there are widely presented science-intensive software products, using the information visualization on the basis of graph models. Since the information that it is desirable to visualize is constantly growing and becoming more complex, more and more situations arise in which classical graph models cease to be adequate. More powerful graph-theoretic formalisms are required and appear to represent information models with a hierarchical structure, since hierarchy is the basis of numerous methods for visual processing of complex big data in various fields of application. One of these formalisms is the so-called hierarchical graphs. This formalism allows selecting in the given classical graph a set of such its parts (so-called fragments) that all elements of each selected fragment deserve separate joint consideration, and all fragments of the selected set form a nesting hierarchy. At the A. P. Ershov Institute of Informatics Systems constructed the Visual Graph visualization system, which is based on hierarchical graphs and allows exploring complex structured big data through their visual representations. In many applications, objects modeled by graph vertices are complex and contain non-intersecting logical parts (so-called ports) through which these objects are in a relationship modeled by arcs. In the paper the formalism of attributed hierarchical graphs with ports is introduced and new possibilities of the Visual Graph system for visualization of large structured data based on attributed hierarchical graphs with ports are considered.

We study the elastic-plastic torsion of a two-layer rod under the action of torque in this article. It is assumed that the rod consists of two layers. Each layer has its own elastic properties, but the plastic properties of both layers are the same. The contact boundary of the layers is located along the oh axis. The lateral boundary of the rod is stress-free, displacements and stresses are continuous at the interface. The components of the stress tensor at a point are calculated using contour integrals derived from conservation laws calculated along the lateral boundary. Next, the second invariant of the stress tensor is compared with the yield strength. At those points where the yield point is reached, the plastic state is realized, in the rest -elastic. This allows you to build a boundary between the plastic and elastic regions. This technique provides a way to calculate elastic-plastic boundaries for the main rolling profiles of rods. This is supposed to be done in subsequent works. We remind you that earlier, with the help of conservation laws, the main boundary value problems for a plastic two-dimensional medium, elastic-plastic torsion of isotropic rods and elastic media for bodies of finite dimensions were solved.solutions.

The development of new ballistic-type aircraft is characterized primarily by improved aerodynamic characteristics and higher speed limits. Ground track testing of aviation and rocket technology is a stage whose task is to confirm the efficiency and effectiveness of new developments. Track tests make it possible to simulate real loads, they are simpler and much cheaper than flight tests. Experimental installation "Rocket rail track 3500" of Scientific Test Range of Aviation Systems named after L. K. Safronov is constantly being upgraded in order to conduct track tests of products at a speed greater than 3M. The experimental setup includes a two-rail track, made on a special foundation, which excludes unacceptable rail deflection with a mass of up to 3000 kg. The rail track has an acceleration section with an angle of attack 2500 m long and a deceleration section. A tray filled with water is made on the braking section between the track rails. It is designed for hydrodynamic braking to a complete stop of the rocket sled with stored equipment. The movable rocket track sled is made of a massive steel plate to which three cross beams are welded. The front and rear beams end with axles on which sliding supports are pivotally mounted. On the rear and middle beams there are lodgements for fastening rocket engines of solid fuel. Depending on the required test speed, from one to five motors can be placed on the cradles. The test object is usually mounted on the front and middle beams along the axis of the sled and fixed in a cantilever, with the head part extended forward. The design of the supports - shoes is made to encircle the rail head in such a way that it provides sliding contact along the upper plane of the rail head, and in the event of a lifting force exceeding the weight of the sled at high speeds, it keeps the structure from free flight by contacting the lower surface of the rail head. Track high-speed tests of special equipment objects are always accompanied by intense vibration and shock effects of structural elements. Due to the desire to conduct track testing of products at a faster rate, it becomes necessary to reduce the level of dynamic loads and eliminate resonant interactions.

The article presents an algorithm and methodology! for statistical processing of random signals of three-axis vibration acceleration sensors installed on the shoes of the rocket track sled and on the fairing of the test object. Due to the placement of registration data storage devices on the sled, experimental vibration data were stored when testing the product at a speed of more than IM. The autocorrelation functions of the signals of vibration accelerations of sensors placed on various elements of the rocket sled, the functions of mutual correlation of the corresponding signals, the density of the amplitude spectra, the density of the power spectra and the transfer functions that characterize the dynamic conductivity of vibrations from the shoes sliding along the rail guides to the test object were determined.

A new concept for building a small-sized rocket engine containing a special gas ionizer in the combustion chamber to increase its conductivity to an optimal value with a corresponding improvement in the fuel combustion process is proposed. A simplified calculation for the relative velocity of gases in a conical nozzle is given when heating the supersonic flow of gases by plasma in a conical nozzle by means of a powerful, electromagnetic, high-frequency field, and the influence of some technical parameters on the efficiency of the rocket's flight is also considered.

A comparison of the flight altitude of a rocket with plasma heating of the gas flow in a conical nozzle with a scale model corresponding to the well-known single-stage Zenit rocket with the same weight and geometry, taking into account air resistance for the cargo version of the rocket with one small-sized engine, is made. The result is a significant reduction in fuel consumption and an increase in the maximum flight altitude by 2 times with an increase in specific impulse by 2.7 times, other things being equal. It is established that under certain conceptual parameters, it is possible to rapidly accelerate and fly a single-stage cargo rocket with a launch weight of 17.25-20.00 tons to the planets of the solar system directly from the Earth's surface using a bunch of engines of the same type.

The use of many of the same type of small-sized engines allows you to abandon the Laval nozzle in favor of a simple conical nozzle, which reduces the size of the rocket as a whole. This is determined by the need to reduce the diameter of the conical nozzle in order to achieve a greater specific heating power of the plasma compared to the specific power of the fuel burned in the combustion chamber. It is also proposed a complete rejection of the steering engines, the function of which will be performed by part of the engines located closer to the diameter of the rocket.

As electric generators, it is proposed to use promising prototypes of electric generators MEG-6NS, MEG-15NS and others, the company "NaukaSoft", with good weight indicators that allow in the future to produce such a liquid rocket engine of small dimensions. The redistribution of part of the fuel used to produce electricity is compensated by a significant increase in the specific impulse of the liquid rocket engine to increase the speed and overall efficiency of the flight with an optimal ratio of the amount of fuel to the weight of the rocket before refueling.

The demand for research of a promising ground-based long-range spacecraft control complex, which has great capabilities not only in the control of deep space vehicles, but also in carrying out fundamental and applied radio astronomical research. Much attention is paid to the analysis of the requirements to the radio complex, which must be fulfilled to realize the possibility of several directions of scientific research and, first of all: planetary radiolocation: interferometry with ultra-long baselines; radio-reflecting; radioastronomy. Based on the analysis of the state of the ground control system of deep spacecraft, the directions of its development on the basis of modernization of existing facilities are revealed, and the prospects for the use of new technologies for the development of deep space on flight paths to the Moon, Mars, other celestial bodies of the solar system, the objects of alien and interplanetary infrastructure are shown.

In this paper, the problematic issues of ensuring the resistance of the onboard equipment of spacecraft to the effects of ionizing radiation from outer space, which significantly limits the period of active existence of the spacecraft, are considered. The paper describes the methodology) for ensuring radiation resistance, developed by the specialists of JSC “ISS”. The result of the work done is to ensure the guaranteed performance of the target function by spacecraft with long period of active lifetime of 15 or more years.

Among the complex of outer space factors affecting the spacecraft, ionizing radiation of outer space is the main factor limiting the period of active existence. Exposure to energetic particles of ionizing radiation from outer space causes degradation of the electronic component base, which leads to failures and malfunctions of on-board equipment and degradation of its functional surfaces. Ensuring the radiation resistance of a spacecraft (SC) is a complex task, one of the stages of which is to determine the radiation resistance of components that complete the on-board equipment. As a result of accumulated experience in conducting radiation tests and analysis of the results, specialists of JSC “ISS” developed a methodology that allows to guarantee the radiation resistance of the spacecraft under conditions of tight production deadlines and optimized costs.

A method of mathematical simulation of the aircraft hydraulic system thermal state is proposed. The mathematical model is a system of partial differential equations for carbon-fiber composite thermal insulation and ordinary differential equations for hydraulic system elements that describe their heat exchange with the air and surrounding surfaces. To solve the direct problem of the hydraulic system elements thermal state, that is, to solve stiff ordinary differential equations, a Rosenbrock-type second order approximation numerical scheme for non-autonomous systems and the solution of a system of partial differential equations, the Monte Carlo method based on a probabilistic representation of the solution in the form of a diffusion process functional expectation were used. The inverse problem of the hydraulic system elements thermal state is solved by the composition of the steepest descent method, the Newton method and the quasi-Newton method of Broyden-Fletcher-Goldfarb-Shanno. A thermal state mathematical model of the hydraulic system unit in an aircraft unpressurized compartment has been developed and the confidence intervals of each of the required model coefficients have been estimated using ${\text{χ}}_{1-\text{α}}^2$  at a confidence probability β = 0.95.

This article presents a methodological approach to designing a spacecraft thermal control system with coolant pumping with a cooling capacity of up to 7.0 kW. Two design options are considered. There is no airtight instrument container in the spacecraft layout scheme, and all heat-generating equipment is located directly on the power structure panels, so excess heat is removed from the spacecraft directly from the outside of the instrument panels.

With all the attractiveness of a two-phase circuit with a heat pipe circuit, its use in automatic spacecraft is complicated by the need to supply concentrated heat to the capillary evaporator of the circuit. To do this, it is necessary to collect heat from a large surface of the structure, on which a large number of heat sources are installed.

A schematic solution of the thermal control system is considered, in which the thermal power of the payload module is distributed between the panel of the service systems module and deployable radiators. At the same time, in the first version, the heat pipes of the payload module are connected to the heat pipes of the service systems module along the profile shelves, the contour heat pipes of the deployable radiator are connected only to the heat pipes of the service systems module. Ums, the heat load of the payload module is transferred to the heat pipes of the service systems module and then to the loop heat pipes.

The second option differs from the first one in that to equalize the temperatures of the panels of the payload module, each heat pipe of the North panel is connected to the heat pipes of the South panel.

From the results of a comparative analysis of the mass budget and energy efficiency, the conclusion follows: the DFC with capillary pumping is the most preferable option 2. which, with the same other characteristics, has a smaller mass. The specific mass-energy: characteristic of such a system is ~22.9 kg/kW.

The purpose of this work is to reveal the patterns of formation of the structure of the surface layer of high-chromium steel subjected to nitriding in a low-pressure gas discharge plasma using a plasma generator with a hot cathode "PINK". Heating of the samples to the nitriding temperature was carried out by the ionic component of the plasma, as well as by the electron and ionic components of the plasma (elion mode). The object of the study was heat-resistant corrosion-resistant steel of the austenitic class grade 20X23H18 (foreign analogue of AISI310S). The relevance of research is due to the relatively low level of hardness and wear resistance of steels of this class. Nitriding of steel was carried out on the TRIO installation, retrofitted with a switching unit for implementing the aelion (electronic and ionic) processing mode. It has been established that the thickness of the hardened layer is (55-60) pm and weakly depends on the method of nitriding, temperature (in the range of 793-873 K), and duration (3-5 hours) of the process. A nitriding regime has been revealed that makes it possible to form a surface layer with a microhardness of 13.7 GPa (ionic heating mode) and 10.8 GPa (elion heating mode). It has been established that the high strength and tribological properties of nitrided steel are due to the formation of a nanocrystalline structure in the surface layer, the main phases of which are iron nitrides Fe4N and chromium nitrides CrN. It is shown that heating the samples to the nitriding temperature in the aelion mode, which uses the electron and ion components of the plasma, leads to a significantly lower level of material roughness compared to the samples heated during nitriding by the ion component of the plasma.

Titanium alloys are hard-to-bond materials due to the fact that a thin oxide film is always present on their surface, which prevents the formation of interatomic and intermolecular bonds between the adhesive and the substrate. In the load-bearing structures of spacecraft (SC), an adhesive bond between a titanium alloy and a composite material is often used. But the strength of such knots is relatively small compared to the mechanical connection. The purpose of this work is to increase the strength of the adhesive joint, due to laser processing of the working surface of the titanium alloy for gluing. Texturing of the surface of the titanium alloy OT-4 was carried out on an ytterbium pulsed fiber laser in 4 processing modes. The treated surface was glued with KMU-4 carbon fiber over an area of 300 mm² using a VK-9 three-component adhesive. The adhesive strength test was carried out on a Eurotest T-50 tensile tester. The test showed that the strength of the laser-treated samples increased by more than 80% relative to the average value of mechanical grinding. The highest value of shear strength was shown by samples with laser processing No. 1 and No. 3. This is due to the greatest increase in the area of bonding of the surface, as well as the mechanical locking of the adhesive in the microrelief of the structure. The increase in shear strength caused by laser surface treatment is a mixed effect of increasing surface area, mechanically locking the adhesive, and changing the surface chemistry. The chemical composition of the surface structure under the influence of laser scanning is gradually transformed from Ti and Ti₂O₃ to crystalline TiO₂. The nature of the destruction of the adhesive joint in the samples with laser processing is predominantly cohesive, but samples with the destruction of the carbon fiber material were also observed, that is, the shear stress in the composite material exceeded the adhesive strength. The effect ofpretreatment of the composite material on the strength of the adhesive joint was not considered in this work.

Technological indicators of electrocontact processing of metals with a vibrating electrode-tool in an electrolyte have been studied quite fully. Knowledge of the erosion coefficient of this processing method will allow us to evaluate the performance of electrocontact processing in advance, at the stage of technological preparation of production.

The article presents the methodology of the experiment, describes the installation based on a linear electrodynamic motor, which allows you to create a vibration of the electrode-tool and electrolyte flow in the interelectrode gap. The results of experimental studies are shown in the form of a graph of the dependence of the metal erosion coefficient on the water velocity in the interelectrode gap at various current densities. Based on the results and previous studies, it was assumed that the erosion coefficient depends in direct proportion to the voltage in the interelectrode gap and inversely proportional to the volumetric heat capacity of the metal and its melting temperature. Based on the theory of electrical contacts and taking into account the features of electrocontact processing in the electrolyte, the definition of voltage in the contact zone has been refined. The theoretical value of the erosion coefficient exceeds the experimental value by two or more times.