Objective. The objective of the study is to consider the application field of modern device development and design methods using the means of 3D modeling and simulation of physical processes. The validity of the application and criteria for the reliability of the results obtained in the sequential design of the mechanical part of the electric drive and the control system are investigated.

Methods. Methods of model representation of 3D objects in computer-aided design systems are considered, as well as methods for solving problems of determining strain under the applied load. Using the example of an elementary joint, the obtained results of the dynamic characteristic of an elastic shaft in a computer-aided design system are compared with those calculated analytically.

Results. The article defines the basic principles and relations applicable to describing the shape of 3D models. Methods are shown by which it is possible to obtain information about the mass-centering model characteristics. The relations that form the basis of numerical methods for solving problems of determining elastic deformations of bodies are also given. The error that can occur when using insufficiently small elementary volumes in solving the problem of determining elastic deformation is shown.

Conclusion. The use of 3D modeling in the design of complex technical systems is justified and speeds up production processes. However, numerical methods cannot always give an accurate result leading to the need to either increase the complexity of calculations or additionally adjust some designed device parameters.

Objective. The article deals with the formation of cost-effective light transistors for creating high-speed energy-efficient computer structures that can solve numerous problems with high speed and accuracy. For this purpose, various types of semiconductor structures are used that can emit and absorb photons for receiving and transmitting digital information.

Methods. The use of mirror electrodes allows for repeated re-reflection of the generated photons inside the light transistor to recover all the generated energy into electricity. This increases the energy efficiency of the transistor as a whole and allows implementing computer devices with high efficiency in solving various tasks.

Results. Most of the useful energy of the information signal is transferred from one electrode to another, and the movement has a higher speed due to the use of photons, rather than drifting electrons, and this indirectly increases the speed of the light transistor by several orders of magnitude and effectively solves the problem of implementing more powerful and high-speed transistors with greater economic benefits.

Conclusion. Prospects for the implementation of high-speed energy-efficient computer structures based on both bipolar transistors and unipolar transistors, as well as thyristors, lasers, and other semiconductor components in light-emitting structures have been developed.

Objective. The objective of the article is to create a design model of a thermoelectric system for extracting foreign objects from the human body by freezing when introduced into the cavity, as well as to study the internal thermophysical processes.

Methods. A design model of a thermoelectric system for extracting foreign objects from the human body by freezing the thermoelectric system introduced into the cavity is developed, based on solving the problem of thermal conductivity, taking into account the thermophysical characteristics of a biological object, foreign object, and a thermoelectric module.

Results. As a result of the numerical experiment, the authors obtained graphs of temperature changes at various points of the thermoelectric system when introduced into the human body to extract a foreign object, depending on the power of the thermoelectric system, the parameters of the module materials, and external conditions. It is determined that the device can use a standard thermoelectric module with a cooling capacity from 4500 W/m² to 7000 W/m² with a duration of 6-7 minutes for entering the system mode.

Conclusion. It is established that the selection of thermoelectric module parameters must be guided by the limitations of the device operation, as well as medical norms and standards to avoid the process of cold injury of adjacent tissues, which is fully provided in the proposed design. A method for improving the efficiency of the system is proposed, according to which the thermoelectric system is pre-cooled using an external cold source, and forced modes of thermoelectric module operation are used.

Objective. The objective of the study is to obtain high-quality and reproducible electrophysical parameters of thin-film metal layers, the formation technology of which determines the reliability and quality of microelectronic products – silicon transistors.

Methods. A method for forming a two-layer titanium-germanium metallization to create a contact and remove heat from the collector junction of high-power semiconductor transistors on the reverse side of plates with formed structures is proposed. The proposed method ensures the quality of the soldered connection and thermal stabilization of semiconductor devices, increasing the reliability of the studied devices in radio electronic equipment systems.

Results. This combination of sprayed metals provides a reliable contact to the collector area when the crystal is placed on the base of the case, which reduces the resistance of the ohmic transition and increases the output of suitable devices.

Conclusion. Based on the results of experimental procedures, the optimal thicknesses of metal layers deposited on the reverse side of transistor crystals were obtained during the formation of metallization to fit crystals on the base of the case. The Ti-Ge system stability is studied. The technical result of the research is to improve the quality of planting by obtaining a uniform distribution of the Ti-Ge layer in a single technological cycle at a given temperature with a certain thickness for each metal separately.

Objective. The objective of this work is to solve an unrelated dynamic problem of thermoelectroelasticity for a long hollow piezoceramic cylinder under the action of an electric load on its surfaces in the form of a potential difference.

Methods. The mathematical formulation of the considered problem of thermoelectroelasticity includes a system of non-selfadjoint differential equations. At the first stage, the authors consider the associated inverse piezoelectric effect problem without taking into account the influence of the temperature field, and at the next stage, study the hyperbolic heat conduction problem (Lord–Shulman theory) for a given (defined) electroelastic field.

Result. A new closed solution to the dynamic inverse piezoelectric effect problem for a long piezoceramic thermoelastic cylinder is constructed. The case of the action of a dynamic electric load in the form of a potential difference on its front surfaces is considered. The ambient temperature and the law of convection heat transfer (3-kind boundary condition) are set. The calculated relations obtained using the generalized method of finite integral transformations allow determining the stress-strain state and thermoelectric fields induced in a piezoceramic element under an arbitrary electrical external influence.

Conclusion. The constructed solution allows determining the stress-strain state and electric field in a piezoceramic cylinder, as well as analyzing the effect of the induced temperature field on the electroelastic state of the system under consideration using the hyperbolic Lord–Shulman theory of thermal conductivity. Analysis of the numerical results allows concluding that there are insignificant energy losses associated with heating the electroelastic system. The developed calculation algorithm is used in the design of non-resonant and resonant piezoelectric measuring devices.

Objective. The article studies the influence of the hull geometry on the towing resistance and speed of ferry vehicles on the water when overcoming water obstacles.

Methods. 3D modeling methods are used in CAD and CAE packages to study the degree of influence of the hull geometry on the water resistance to the movement of the ferry vehicle, which makes it possible to accurately model the working processes occurring when flowing around motor ferries.

Results. The analysis of the results of computer simulation of the movement of a ferry vehicle of the original design on the water is carried out. The advantages and disadvantages of the ferry bridge machine of the original design are determined, and various variants of design and layout schemes are proposed, the use of which allows increasing the speed and maneuvering characteristics of ferry vehicles.

Conclusion. A variant of the design and layout scheme of a motor ferry is proposed, which allows improving the hydrodynamic characteristics of the ferry vehicle body by using modern technical solutions aimed at reducing towing resistance and increasing the speed of transportation when overcoming water obstacles.

Objective. The objective of the study is to develop a design model of the electronic equipment cooling system based on the combined use of high-current thermoelectric semiconductor batteries of layered design and an evaporative-condensing thermal thermosyphon, as well as to study the thermophysical processes occurring during its operation.

Methods. A mathematical model of the electronic equipment cooling system based on the combined use of high-current layered thermoelectric batteries and an evaporative-condensing thermal thermosyphon is presented. The design model includes a description of heat exchange processes in a layered thermoelectric element at various supply currents, determination of the amount of heat transferred through the cross-section of the channel of a thermal thermosyphon per unit of time, and the temperature values at each channel point.

Result. A 2D dynamic heat conduction problem is solved for a complex system with rectangular geometry of fragments and heat sources. The temperature distribution of a thermoelement along its longitudinal axis at different values of the supply current and the change in the heat flow along its length in a thermal evaporation-condensation thermosyphon are studied.

Conclusion. The results of the research have shown the effectiveness of combined use of high-current layered thermoelectric batteries and a thermal thermosyphon in electronic equipment with dense element packaging. It is shown that to increase the efficiency of electronic equipment and reduce the heat losses that occur in the heat line when the heat-generating element of radio-electronic equipment and thermoelectric semiconductor batteries are separated by a sufficiently large distance (over 0.6 m), it is advisable to use an evaporative-condensing thermal thermosyphon as a heat line.

Abstract. Objective. This article studies the problem of increasing the efficiency of fuzzy controller synthesis in a control system using a genetic algorithm. The best parameters of the fuzzy controller are selected using the crossing-over and mutation operators in the genetic algorithm. The operation of the mutation operator can lead to the formation of an incorrect set of parameters, which complicates the procedure for synthesizing a fuzzy controller.

Methods. Arrays of parameter sets of membership functions, conclusions, and rule weights that are included in the fuzzy controller are compiled using mathematical simulation. The mechanism of operation of single-point and two-point variation operators in the genetic algorithm is described by the simulation modeling.

Results. Mathematical models of single-point and two-point variation operators for the genetic algorithm are proposed. The mechanism for changing the values of elements in the array of a set of parameters of a fuzzy controller with one input and output variable is presented.

Conclusion. Replacing the mutation operator with the variation operator eliminates the formation of incorrect sets of parameters of the fuzzy controller in the control system.

Objective. A study of the structure of the earth's crust by determining the velocities of seismic waves from previously broken sections of the earth's crust.

Methods. Two mathematical methods are proposed for determining the seismic wave velocities. The first is based on the weighted average method, and the second is based on the matrix method for solving systems of linear algebraic equations. The initial parameters used in the calculations are data from earthquakes that occurred – the coordinates of earthquake centers of origin and seismic sensors, as well as the travel times of seismic waves from the earthquake center of origin to the seismic sensors.

Results. The problem of determining the propagation velocity of seismic waves in different parts of the earth's crust is solved by two different methods. The distribution densities of errors in determining the seismic wave velocities are obtained for the weighted average method, in six different situations, for the distribution of seismic wave velocities on the ground, and the matrix method, in the case of distribution of seismic wave velocities on the ground in staggered order.

Conclusion. The proposed methods allow refining the coordinates of the centers of the occurred earthquakes while using the iteration method can significantly improve the accuracy of determining the coordinates of the earthquake center of origin and the speeds of seismic waves in various areas. The presence of seismic wave velocities in various parts of the earth's crust during calculations allows determining the coordinates of the earthquake source using new methods based on the use of second-order hyperboloid figures, which were not previously used by seismologists.

Objective. A family of multilayer finite elements designed for calculating reinforced concrete slabs and shells of variable thickness is described. The features of the formation of stiffness matrices associated with the variability of the cross-section of elements are considered.

Methods. The family is based on the simplest planar triangular element constructed using the Kirchhoff hypothesis. The transverse displacements in this element are approximated by an incomplete cubic polynomial. This element is not suitable for practical use, but it is based on improved elements of three- and foursided shape in the plan. Special attention is paid to the consideration of cross-section variability.

Results. The results of testing the developed elements are presented and the advantages of their use in the practice of design and calculation of structures are shown.

Conclusion. The developed PRINCE software package can be useful in the design and calculation of structures containing plates of variable thicknesses.

Objective. The objective of the study is to determine the requirements for various devices of hydraulic reclamation machines, which are widely used in the construction of canals and drains, to maintain a given slope, as well as the calculation of the executive mechanism that serves to eliminate the oscillating movement of the working body relative to the line of the specified slope.

Methods. A mathematical description of the vibrations of the working body for caterpillar hydraulic reclamation machines with mounted working bodies is given.

Results. The article presents the results of research to identify the main factors affecting the oscillations of the working body of caterpillar reclamation machines. As a result of theoretical and experimental studies, it was found that when a caterpillar machine with a rigid undercarriage crosses single and multiple irregularities, the movement of the cutting edge of the rigidly mounted working body is graphically depicted by sinusoidal curves. The obtained dependencies allow conducting calculations of the automatic system of maintaining the specified slope and establish the area of stable modes of system operation. A geometric method for optimizing the hinge linkage of the working body of trenchless pipelayer is presented.

Conclusion. The proposed methods of improving the performance of caterpillar hydraulic reclamation machines with mounted working bodies when moving on uneven ground surfaces can be used to create a wide class of mounted earthmoving machines, both with passive and active working bodies.

Objective. The article describes the features of works on coastal protection of territories subject to slope processes. The role of research of leading processes of destruction of coastal zones in the framework of the program “The Ecology of Safe Construction and Municipal Services” for forecasting and preventing risks, as well as providing information for further work on building reliable coastal protection, is emphasized. Despite the existing variety of ways to protect embankments from erosion, the search for new technical solutions at the moment continues to be an urgent task.

Methods. Geotechnical monitoring of hydraulic structures was carried out. Visual assessments of cracks, slopes of individual structural blocks, and deformations were performed. A thermal imager device is used to search for abnormal temperatures and an electronic hardness meter that measures the strength of concrete.

Results. It is determined that the water regime of the Astrakhan Region is characterized by an uneven distribution of runoff due to a direct dependence on the flow rate from the Volgograd hydropower plant. The predominant source of moisture is discharges in the form of a series of rain floods, which often cause flooding. One of the most effective solutions is to preserve the operational characteristics of the bank protection spur-pile of variable cross-section when changing the hydrological river regime. The bank protection spur runs partially movable horizontally and vertically and comprises a head spur in the form of piles of variable height; the body in the form of a floating garland of variable cross-section; the base in the form of a slider block. The design and technological solution allow blocking the coastal stream with the body of the spur at any water level and changing the angle of inclination of the spur with the protected shore.

Conclusion. Prevention of emergencies, especially in urbanized areas that are subject to intense anthropogenic impact, is possible only when engineering protective structures are built, which have a positive effect both in protective and environmental aspects.

Objective. In this study, the task is to establish the theoretical prerequisites for the operability of a regressive-progressive elastic mechanism by comparing the amplitude-frequency characteristics and phase trajectories with a linear elastic system of comparable stiffness in a static equilibrium position.

Methods. The article presents a comparative dynamic analysis of vibrations of elastic systems with linear rigidity and regressive-progressive characteristics obtained as a result of the use of elastic elements in the form of high flexibility rods with longitudinal eccentric compression. Such elastic elements in various design variants have been tested and patented as damping elements for use in the construction of vibration dampers for construction structures and vehicle suspensions, and have experimentally shown their effectiveness in damping vibrations.

Results. The regressiveprogressive elastic characteristic obtained by the elliptic parameters method and using the ANSIS calculation complex is used in the dynamics equations in an approximated form, which expands the capabilities of the method. It is shown that increasing the energy intensity of a curvilinear system reduces the vibration amplitude.

Conclusion. The regressive-progressive change of the stiffness of curvilinear elastic systems can be achieved using an elastic element with eccentric longitudinal compression; the regression plot of elastic properties is achieved due to eccentric compression; the progressive plot – through the use of a guide or other design solutions. The implementation of this characteristic allows using such elastic mechanisms in systems where the accumulation of potential energy occurs with a smaller compression stroke for the same perturbation than for linear systems.

Objective. The article deals with the problem of ensuring the rigidity of a frame wooden multi-story building and ways to achieve the necessary spatial rigidity, taking into account the requirements of preserving the internal volume and free space. The case of excess spatial rigidity and measures to optimize it are provided to increase the economic efficiency of the project.

Methods. A simpler and less time-consuming method is the initial estimation of the cross-sectional area of the rigid elements that take the wind load. The authors propose a method for the preliminary calculation of building stiffness with subsequent adjustment in the calculation scheme.

Results. The design scheme of the building frame is made in the Scad Office software package to take into account the influence of the own structure weight, the redistribution of forces and movements due to the spatial work of the frame, with subsequent adjustment of the cross-sections of rigid elements.

Conclusion. The most rational and least time-consuming method for numerical calculation of stiffness is the initial estimation of the cross-sectional area of the system of rigid elements. With its help, it is possible to avoid an excess of spatial rigidity of the building and reduce the time and labor costs for selecting the location of rigid elements.

Objective. The objective of the research is to design strutted beams that have optimal parameters for metal consumption.

Methods. A mathematical simulation of the operation of a strutted beam with elastic support in the middle of the span is used. The calculation formulas are obtained based on the solution of the corresponding differential equation of the transverse bend of the upper crossbar of the strutted beam.

Results. A method has been developed to optimize the design parameters of a single-strut beam. Constructive calculation schemes are given, as well as formulas that allow assigning design parameters ensuring a minimum of metal consumption while maintaining the technological simplicity of manufacturing a strutted beam. An algorithm is constructed that can be used to design single-strut beams. The resulting calculation formulas are brief and easy to use.

Conclusion. The proposed method allows reducing the weight of a single-strut beam by up to 60% compared to conventional beams.