Integrated Computer Technologies in Mechanical Engineering - 2020

The work deals with the study of some problems of reconstruction multidimensional statistical dependences on the basis of empirical data by means of artificial neural networks. To provide stability (robustness) of systems and processes statistical model parameters on the basis of trained artificial neural networks (ANN) at the a priori input data uncertainty as well as practically sufficient accuracy of data approximation, it is appropriate to use stable (robust) methods of deep ANN training methods. The work uses the cricking model for statistical data since we couldn’t get precise parameter values; therefore, to achieve the required accuracy, some probability was introduced. The synthesis method of scalar convolution of selection functions for mathematical model identification, based on the law of requisite variety (Ashby law), Kolmogorov power overage concentration and the maximum likelihood principle, where Student and Romanovski statistics, are used as the proximity measure of true multidimensional samples. It makes it possible to structure preference systems of a person who makes decisions for multi-criterial problems to identify mathematical models in determinate and stochastic formulations (MV-, MH- problem). Neural network identification was made by the stochastic approximation method on the basis of ravine conjugate gradient method. The method of effective robust estimation of statistical model systems parameters was worked out by employing a regularizing sequential (adaption) algorithm for synthesis of solutions with deferred correction. Samples of Rosenbrock function data and corresponding parameters of aerodynamic characteristics of the jet engine multistage axial compressor were taken as examples.

Wavelet-based image compression techniques, in particular, SPIHT have an obvious advantage of providing a desired compression ratio. However, for a given compression ratio, quality can vary in wide limits and it can be unsatisfactory for a given image, especially if it is highly textural. Then, one needs to choose and set another compression ratio providing an appropriate quality of the compressed image. Often, this adaptation should be done quickly and with providing high accuracy of reaching a desired quality. In this paper, we propose a fast and efficient approach to predict quality of images compressed by SPIHT using two favorable facts. Firstly, a fast procedure of quality prediction has been proposed for the coder AGU based on discrete cosine transform. Secondly, performance characteristics of SPIHT and AGU are quite similar. This allows recalculating predictions obtained for AGU to predictions for SPIHT and decision undertaking concerning parameters of image encoding by SPIHT.

Time delay estimation (TDE) for signals arriving at interferometric or array antennas is an operation widely used for different applications. There are efficient solutions for fixed (not moving) sources of irradiated or reflected signals under the condition of high input signal-to-noise ratio (SNR), the appropriate interval of signal reception and Gaussian noise. However, efficiency and accuracy of estimation considerably reduce if noise is not Gaussian and SNR is low. Available solutions require pre-processing of received signals that often takes a lot of time and efforts. Here, we propose another solution for the interferometric case that can be treated as looking for the robust similarity of received signal/noise mixtures for a set of possible delays. It is shown that such processing is fast and efficient providing considerable improvement of TDE accuracy in the sense of sufficient reduction of probability of abnormal estimates for the non-Gaussian environment.

A special class of atomic functions, which are compactly supported solutions of linear functional differential equations with constant coefficients and linear transformations of the argument, and their basic properties are considered. Spaces of linear combinations of shifts of these functions are given. Such spaces have good approximation properties and combine smoothness of elements with an existence of compactly supported basis. For this reason, their application to solution of different problems is perspective. System of atomic wavelets, which is a basis of such spaces, is a practical tool for data analysis and processing. The aim of this paper is to analyze atomic wavelets expansion algorithm in terms of complexity. Using properties of atomic functions and atomic wavelets, it is shown that expansion algorithm has linear time and memory complexity. Moreover, the numerical scheme can be easily parallelized. This means that application of atomic wavelets is promising especially when processing digital images and video.

A cloud platform is proposed within the framework of PaaS and SaaS models, which provides support for all stages of the development of intelligent decision support systems, their adaptation to solve applied problems for IoT and control applications in industrial automation systems, storage of knowledge and data bases in cloud data centers, provision access to intelligent systems as services remotely through a web interface. Use scenario and tasks to be solved are considered. The IoT platform structure of intelligent control systems is presented. Examples of creating intelligent systems in Node-RED are considered.

An analysis is made of the vehicle safety from the point of view of the possibilities of increasing it. Criteria are proposed for assessing active, passive, post-accident and environmental safety. The possibility of increasing the safety of vehicle operation by enhancing the use of informative security, that is, providing the necessary information to the driver and other traffic participants, is being considered. Control schemes for general vehicle safety systems, lighting, engine and braking are offered. At the same time, the Arduino controller and the DFPlayer mini module are considered as a control unit when modeling a car voice informant.

When measuring moisture content in oil products using capacitive moisture meters we face with method error named ‘type uncertainty’, caused by different values of dielectric permittivity for different oil products in dehydrated state, which depend from geographical origin, processing conditions etc. and can be hardly predicted automatically. The main task of the research is to reduce this type of method error by developing special measuring instruments. A prototype product of the instrument measuring transducer had been developed and experimentally tested together with the special method of moisture measurement which includes two additive, two multiplicative and two complementary testing influences on the substance under research. Moisture content with nominal values 0%, 10%, 20% and 30% was reproduced by two oil products with different dielectric permittivity values: transmission oil (ɛ = 2.01) and mazut (ɛ = 2.67). Experimental setup of an adaptive moisture meter was assembled using the substitution method of measurement to provide good accuracy for the conditions of capacitance measurement in substances with significant dielectric losses.

A new sorption-capacitive gas humidity sensor was suggested. It’s technical composition provided better sensitivity in comparison with closest analogues. Calculations of initial capacitance and sensitivity of a new sensor and two closest analogues were done. Theoretical calculations confirm significant advantage in sensitivity for suggested humidity sensor. Three prototype products of capacitive humidity sensors were manufactured to fulfill experimental researches. Static generator of humid gas with salt solutions was used to reproduce values of relative air humidity in a range from 33% to 93%. Results of experiments confirmed the results of theoretical researches and proved that new humidity sensor has two times better sensitivity in comparison with two closest analogues.

The measurement and control photoelectric methods of the angular displacement of the aircraft control surfaces have been considered. Their application makes it possible to automate these processes and implement them without changing the aircraft design. Their main advantages and disadvantages have been listed. The functional schemes implementing these methods have been shown.

Under the new paradigm of exploration of space, both near and distant, continue using mini-, micro-, nano -, pico satellite armadas or fleets (compound dynamic systems – CDS). These CDS will be arranged in clusters in such a way that clusters made up of an excess of small satellites (mini-, micro-, nano-, pico-satellites) have increased functional stability and the quality of assigned functions. The efficiency of the CDS, consisting of thousands of small satellites (micro-, nano-, pico-satellites) will be determined by how efficiently the clusters of the required configuration are created, held (stabilized) in the created configuration, and reconfigured. Clusters for various practical purposes: communications; telecommunications and global Internet; navigation; monitoring of the Earth’s surface, troposphere, stratosphere, ionosphere and exosphere have specific features. However, the common feature of all specialized clusters – they should be rebuilt (change the spatial topology) in a minimum time and stabilized in a new configuration at rational (preferably with minimal) energy costs. This article is devoted to the development of a method for designing (formation) low-orbit clusters of small satellites with a given spatial topology and stabilization of this topology in terms of rational energy costs under the action of stochastic disturbances. The method consists in the synthesis of control actions that are technically easy to implement using the small satellites’ onboard hardware. Control actions allow to form a low-orbit cluster satellite (LCS) in a minimum amount of time and to keep the LCS in a configuration that differs little from the required.

The study of individual systems of air traffic controllers’ (ATC) preferences on the dangers of characteristic errors has a positive proactive character. Group systems of preferences (GSP) reveal features of functioning of separate societies – ATC’s shifts. Individual systems of preferences m = 37 tested air traffic controllers were built. The implementation of a multi-step technology for detecting and rejecting marginal thoughts has led to a statistically consistent GSP: Kendall's concordance coefficient is W = 0.700 and is statistically significant at an unusually high level of significance for human factor research α = 1%. A decision matrix has been formed – a “cost matrix”, for the solution of which the methodology of application of classical decision-making criteria by Wald (W), Savage (S), Bayes-Laplace (B-L), Hurwitz (HW) has been implemented. Empirical preferences coincide: the values of Spearman's rank correlation coefficients are equal to $$R_{S}^{B - L - W/S}$$ R S B - L - W / S  = 0.8922, $$R_{S}^{B - L - HW}$$ R S B - L - H W  = 0.9263 and are statistically significant at the level of significance α = 1%. The values of the normalized risk index of indistinguishability of error risks in group systems of advantages are equal to: $$R_{BL}^{*}$$ R BL ∗  = 0, $$R_{HW}^{*}$$ R HW ∗  = 0.19⋅10–2, $$R_{W/S}^{*}$$ R W / S ∗  = 5.58⋅10–2. For the group as a whole $$R_{g}^{*}$$ R g ∗  = 0.52⋅10–2.

The possibility of using microelectromechanical system (MEMS) of the mobile devices to physics learning is the main subject of this work. We have used the smartphone as a tool for physics measurements. The proposed solution illustrates the easing of smartphone use in experiments for physics learning. Other sensors can also be integrated into physics training experiments. The drawbacks of each embedding sensor can be suppressed by using the sensor data fusion. The evolution of the developed application should be carried out in the following directions: use of augmented reality technology in order to make the obtained results more demonstrative and understandability, algorithmic integration of measurement results by different sensors, application of modern methods of digital filtering in the application. The concepts discussed in this paper can prove useful to both students and teachers for the practical implementation of a virtual laboratory workshop to study the laws of mechanics at universities.

At the moment, there are many methods of analysis and classification aimed at building the most accurate and effective mathematical models that are widely used in medicine as a decision-making tool. Existing methods make it possible to identify the relationships between input and output variables in the sample, build models reflecting these relationships, compare them in terms of accuracy, profitability and costs, and choose the most effective model. The increase in the incidence of diabetes not only in the world, but also in Ukraine, dictates the need to introduce a mathematical apparatus for automatic diagnosis of the disease. Within the framework of the study, the classification of patients with diabetes by the logistic regression method was implemented. Python is used for software implementation.

The presented paper deals to create a conceptual model of information security. The purpose of the paper is to investigate existing models and develop a first-level conceptual model and lower-level models. The above analysis of existing models showed their main disadvantage. This is the absence of any dialectical connections between model elements. Such schemes are primitive in terms of their use in the organization of protection systems. The proposed model allows you to look at the task of creating information protection systems taking into account the impact of vulnerabilities on possible scenarios of attacks by the intruder, the impact of detected vulnerabilities on the protection system, in terms of its improvement, the possibility of passive counteraction to the actions of the intruder. The second-level models examined the elements of the first-level model in more detail, which made it possible to penetrate more deeply into the ideology of creating protection systems, including proactively depriving some of the capabilities of a potential violator.

The article describes the perks of the serverless and containerization models and methods in challenger banks software. Data sovereignty in the context of microservices means that the stored model of the domain may differ same between subsystems. This approach to data modeling creates an easier way to write a query that merges data from various sources. Microservices intercommunication methods shows that typical microservices-based application is a distributed backend running as multiple processes, in most cases on multiple hosts in the same network. Service in the simplest case is just a process which can interact with other parts of the system. Methods of identification of the domain boundaries for each service imply the goal which should be to achieve the most meaningful separation leaded by your (or some expert’s in your team) domain knowledge. The main idea here is it’s not the size, that matters, but business capabilities and concerts separation. Methods for handling transactions in asynchronous distributed system show that each service is usually an isolated system apart with its own dedicated database. This means you can no longer take advantage of the 2PC to maintain the consistency of the whole system. Dealing with transient errors, eventual (in)consistency between microservices, isolations, and version rollbacks are scenarios that should be considered during the design phase.

Currently, there are a lot of training systems for acquiring programming skills, and at the same time there is an acute shortage of tools that would allow to acquire and improve the skills of various user groups in the field of algorithmization. The aim of the work is to develop an Intelligent Tutoring System that supports various user groups in the study of algorithms and their application in various practical fields. In the work we used the method of intellectual computer training in algorithmic thinking of various user groups through deep diagnosis and adaptive prompts. The proposed models and method are implemented in the ITS prototype, the work of which is demonstrated on the example of training medical staff, aircraft pilots and students in three different subject areas. The experimental operation of the system has shown its effectiveness in the areas considered. From a scientific point of view the information technology of training in the compilation of algorithms in the form of flowcharts based on new models and methods is one of major interest. In practical terms the developed prototype of a web system for adaptive training in algorithms with the potential to expand the circle of users and problem areas is of great value.

Analysis of scientific opinions on the content of criminal law policy for countering cyberterrorist attacks on critical infrastructure and aviation. Scientifically substantiated recommendations concerning the directions of counteraction to cyber incidents are given and the innovation development algorithm for the needs of law enforcement agencies is offered.

Currently, the use of intaglio printing for applying the adhesive on the foil is a promising way to obtain the honeycomb core with high geometric characteristics of a cell. In this method, adhesive strips are featuring the structure with a number of individual points of specified thickness and size, ensuring high accuracy of resulting strips and, accordingly, honeycombs’ characteristics. The paper specifies the field of tolerances for the technological parameters of the process of adhesive application using the intaglio printing method. Due to the fact, that adhesive strips in the intaglio printing are applied on the foil as discrete microzones, the geometrical mathematical models for the relationship of adhesive amount applied and its thickness are proposed and implemented. These models and the method implementing the same allowed establishing the tolerance field for the adhesive application depending on its final thickness formed in the honeycomb pack molding operation. The mathematical model and method for determining the relationship of uneven tearing strength of the adhesive layer as an integral characteristic of the adhesive tensile strength, elastic moduli of the foil and adhesive, as well as thickness of the foil and adhesive layer, is proposed and introduced. The resulting analytical dependence allows finding the tolerance field for the uneven tearing strength to be realized in the function of the nominal adhesive thickness, which is implemented in a specific technological process. The results, in the aggregate, allow significantly reducing the amount of technological preparation of considered stages of the technological process for the manufacturing of honeycomb cores by means of reduction of the experimental research.

The paper proposes both theoretical and experimental approaches to the analysis of laminated composite response to impact loading. For theoretical modelling of dynamic behavior of a composite, the generalized model is used that takes into account the spatial character of deformation on near to the impact point. This model is based on a power series expansion of the displacement vector component in each layer for the transverse coordinate. The results of calculations are compared with the data obtained by other researchers for the case of low-velocity impact, as well as with the experimental data obtained by ourselves at medium-velocity impacts on composite panels. In the experimental study, maximum deflections of composite samples during the impact of an indenter were investigated. A pneumatic gun was used to launch the indenter, and a crusher was used to register the maximum deflections. An experimental study of the response of an eleven-layer fiber-glass composite to indenter impacts at different velocities was performed. For launching, the 600 g indenter was used. It is established that the calculation results and experimental data are in good agreement.

A subject of the study is ways to determine the volume of vessels with complex shapes. The work aims to develop and scientifically substantiate a rapid method of measuring the volume of the vessel’s inner cavity with complex geometric shapes. The following results were obtained. Invented method of rapid measurement of the vessel volume with complex shape bases on a critical outflowing filled gas and its drainage through a nozzle with a predetermined discharge coefficient. The dynamic pressure change in a vessel is a determining parameter of its volume. Two conditions must be met for this method to be accurate. The first one is the calming of transients in the measured vessel after the beginning of gas critical outflow and the second is providing an adiabatic flow. The proposed method of measuring the vessel volume was checked by simulating. Obtained results show the accuracy of determining the volume of about 0.06% compared with CAD system data. In practice, the measurement by the method should be performed in two stages. At the first stage, the value of the nozzle discharge coefficient must be found based on the results of the control measurement when flowing out of the etalon vessel with a known volume. At the second stage, the required volume is determined using the found nozzle discharge coefficient. We expect the duration of the direct measurement by the invented method up to 1 s and its accuracy by about 0.1%.

A method is proposed for solving the problems of optimal design of cyclically symmetric structures under static loading, which has been tested on critical structural elements of hydraulic turbines. One of the basic problems in the design of hydraulic turbines is considered, namely, ensuring their strength and reliability under continuous operation under the influence of a static loading. The problem of optimal design of the initial and modified covers of a rotary-blade hydraulic turbine operating in the normal mode has been solved. A Kaplan turbine cover is a complex spatial structure consisting of thin-walled elements. Therefore, the finite element method is used for the calculation to most fully take into account the design features and the spectrum of external influences acting during operation. As the initial design, covers with an initial and modified hole in the rib were selected. The geometric parameters of the cover are modified to minimize the cover weight. The thicknesses of structural elements are taken as design variables. The minimum and maximum thicknesses, as well as maximum stress intensity values are limited. The objective function is the cover weight. The problem of optimal design is solved with the help of the gradient method using a finite-difference analogue of a gradient of the objective function. The distribution of axial displacements and stress intensity in the original and modified cover design during normal operation was obtained. It was found that the mass of the cover structure was reduced by 30%, and the rolled stock thickness range was downsized by five positions, which is significant in the manufacture of a new design. In this case, the stress values in the optimal structure during the modification of the hole in the ribs did not exceed the admissible values. The proposed approach will subsequently be applied to the analysis of elements of aircraft structures.

Investigating dynamic response parameters for impact loading is a key effort in analyzing vibrations of laminated composite structures. The work presents an analytical approach to vibration analysis of laminated orthotropic shells with a complex plan shape under low-velocity impact. The dynamic behavior of shells is described by the first-order theory. The equations of motion of shells and boundary conditions are obtained from the Hamilton’s variational principle. The motion equations are added by the indenter equation of motion and the condition of joint displacement of the indenter and shell. The analytical solution of the problem is derived by the immersion method. The system of motion equations of shells is integrated by expansion into Taylor series. The method potentialities are demonstrated by calculating deflections and stresses in orthotropic shells with different boundary conditions. A good match of results obtained by different methods confirms the feasibility and effectiveness of the method offered.

The paper shows the possibilities of using the measuring and computing complex of electronic speckle pattern interferometry (ESPI) to determine the vibrational dynamic parameters of structural elements. The characteristics of the methods for obtaining patterns of bands by the method of difference speckle correlation and the proposed method for determining the contrast of the dynamic speckle pattern are compared. A comparative analysis shows their equivalence in the quality of interferograms and the information content of the obtained data. At the same time, varying the volume of the processed specklegram buffer makes it possible to reduce the influence of the instability of the optical parameters of the interferometer and the electrical control signals of the experiment on the test results. A slight increase in the inertia of the response to a change in the oscillation regime results in a significant decrease in the sensitivity of the installation to external disturbances, which, in combination with the noise-resistant optical circuit of the interferometer, allows the complex to be operated in off-stand conditions.

High requirements are imposed on rapidly developing rocket and space technology. One of the most important requirement is the acoustic influence on the structure. In this regard, there is a need to search for methods for predicting and modeling the reaction of individual structural elements of rocket and space technology. Electric energy sources play a prominent role in creation and ensuring the operability of space and rocket technology. These sources are usually solar batteries. The frames of solar panels in the form of ultra-lightweight rigid sandwich panels made of polymer composite materials with honeycomb are most widely used. The paper presents an approach to determining the stress-strain state of solar panel during acoustic loading. The implementing approach is presented in the form of a block diagram with a detailed description of each of the four blocks highlighted below. «Input data» is the definition of the acoustic loading spectrum, material characteristics and panel shape. “Preliminary design” is the definition of the reduced characteristics of the solar panel and the definition of the method of representation the loading. «Finite-element method» is the analysis of either random vibrations or harmonics of a steady state in the package of the finite element method. “Output data” is the selection of interest data obtained from the designing by the finite element method and their subsequent analysis. The developed approach will be useful for enterprises to introduce into the structure analysis process of rocket and space technology for strength under acoustic influence.

Using of condensing low-temperature heating surfaces in exhaust gas boilers allows to increase the economic efficiency of boilers and thermal power plants. Analysis of literary sources showed, that there were no quantitative data of the low-temperature corrosion intensity of exhaust gas boiler low-temperature heating surfaces while water-fuel emulsion combustion. Experimental investigations of corrosion processes of low-temperature heating surfaces in exhaust gas boilers with excess air factor in the range of 1.5…3.0 were carried out. The empirical correlations for dependence of specific metal mass loss on water content of water-fuel emulsion, sulfur content in output fuel and excess air factor α at wall temperatures below the dew point temperature of sulfuric acid vapor, which characterize the low-temperature corrosion intensity of condensation surfaces at different operating modes of exhaust gas boilers were received. For estimation of the influence of the quality of combustible fuel and its combustion regimes on the corrosion intensity, a computer simulation was conducted by using the statistical program package Statgraphics Centurion XV. These correlations show that the smallest values of corrosion intensity are observed at large values of water content in water-fuel emulsion of about 30%. The minimum values of exhaust gas temperature at the exit from exhaust gas boiler and of wall temperature are determined, at which the permissible speed of low-temperature corrosion at a level of 0.25 mm/year is ensured.

Local damage repair of modern aircraft structures can be done by creating patchs that are glued to the main structure. The patch takes on part of the load, unloading the damaged area. This method of repair provides tightness and aerodynamic efficiency of the structure. The stress state of such glued structures is calculated, as a rule, using the finite element method. Classical models of the lap joint stress state are one-dimensional. I.e. the change in the stress state is considered only along one coordinate. In this case, the joint is considered rectangular. The aim of this work is to create a mathematical model of the stress state of circular axisymmetric adhesive joints, and to build an appropriate analytical solution to the problem. It is assumed that there is no bending and the deformations of the plates are uniform in thickness. The adhesive layer only works on shear. Both plates – the main plate and the patch are assumed to be isotropic. The solution is built in the polar coordinate system, in which the stress state of the joint depends only on the radial coordinate, i.e. is one-dimensional. The solution is obtained in an analytical form. This mathematical model is a generalization of the Wolkersen classical adhesive joint model for a circular or annular domain and is considered for the first time. The model problem is solved. The calculation results are compared with the calculations performed using the finite element method.

The growth of the cruise industry leads to the proliferation of the fleet of cruise ships, but it will increment the atmospheric emission. The International Maritime Organization (IMO) has imposed restriction on the various pollution components of exhausted gases from ships, including carbon dioxide that contributes greatly to the greenhouse effect and is an indicator of energy efficiency for maritime transport. In this paper, ten cruise ships built in 2013–2019 with basic diesel-electric power plants are considered. The schematic diagrams of the alternative combined gas-turbine-electric and diesel-electric power plants applying thermochemical regenerators fed by exhaust gases have been developed for vessels under consideration. Energy efficiency design index for the cruise ships with both the basic and alternative power plants operating on marine fuel oils, liquefied natural gas and syngas has been estimated and compared with the IMO guideline values for this type of vessels. It has been revealed that the application of the thermochemical technologies of waste heat recovery increases the energy efficiency of cruise ships by 15–25%.

The paper is devoted to the consideration of existing methods of deposition of hardening coatings. The paper discusses the relationship between the coating deposition process and the control circuit for the ion current density and energy control. The analysis of deposition methods is carried out and on the basis of this analysis the CIB deposition method of hardening coatings is selected. The authors studied the features of each of the considered methods, which made it possible to identify the main advantages and disadvantages. Based on the data obtained, it шs revealed that for equal-thickness coatings, it is necessary to use control circuits for the ion current density and energy.

The paper offers an analytical solution of the problem of the stressed state of an infinite plate with a circular opening reinforced with a concentric round cover plate. The cover plate is assumed to be elastically attached to the main plate along its perimeter. The structure is loaded at infinity with uniform tension. The solution is obtained by expanding the components of the stress-strain state into a Fourier series about the angle coordinate. After satisfying the edge conditions, the solution retains only the first series terms. The model problem is solved. The cover plate was shown to reduce the stresses near the opening. The solution was verified by comparing computational results with calculations performed using the finite element method. The model suggested is highly accurate. A parametric study was performed to examine the impact of cover plate thickness and plate thickness ratios, and cover plate radius and opening radius ratios on the stress in the most loaded section.

The paper considers the reasons for the occurrence of dynamic stresses in a conveyor belt made of composite materials, the properties of which can be described by the Kelvin-Voigt model of an elastic element. A boundary value problem for the equation of elastic vibrations in a lightly loaded conveyor-type transport system is formulated. The dependencies determining the forces of resistance to the movement of the belt correspond to the recommendations of DIN 22101:2011-12. An expression is presented that determines the speed of propagation of disturbances in the conveyor belt, taking into account the uneven distribution of material along the transport route. The reasons for the appearance of elastic stresses in the conveyor belt associated with the start, acceleration, deceleration and stop of the transport conveyor are demonstrated. Dimensionless parameters were introduced to analyze the causes of dynamic stresses in the conveyor belt. Similarity criteria in the dimensionless transport conveyor model make it possible to use the results obtained for similar transport systems. It is shown that the value of static stresses for lightly loaded transport systems is characterized by a linear dependence on the distance between the belt element and the drive shaft of the conveyor section. The solution of the boundary value problem defining the expression for dynamic stresses in the tape is presented. It is shown that the decay speed of the arising disturbances is inversely proportional to the value of the viscosity coefficient of the composite material, which characterizes the mechanical properties of the conveyor belt. A qualitative assessment has been made for the characteristic decay time of dynamic disturbances in a conveyor belt.

The paper proposes a method for constructing an algorithm for the speed control of a conveyor belt, based on the change in the price of electricity during the day. The analysis of methods for improving the energy efficiency of conveyor-type distributed transport systems is carried out. The influence of the uneven distribution of material along the transportation route on the cost of transportation of a unit weight of the material is demonstrated. The advantages of using Time-Of-Use (TOU) tariffs when designing belt speed control systems for long conveyor systems are considered. The TOU periods with peak, standard and low energy consumption depending on time are presented in detail, as well as the values of the tariff coefficients for the TOU periods. The dependence of the value of the tariff coefficient on time is an essential factor that must be taken into account when designing control algorithms. When developing the control algorithm, it was assumed that the resistance to motion in accordance with DIN 22101 is determined on the basis of the primary friction coefficients. To describe a separate section, an analytical model of the conveyor in a dimensionless form was used. The problem of constructing an optimal algorithm for controlling the speed of a conveyor belt for a steady-state is formulated. The criterion of the quality of the control process in the conditions of using a constant amount of electricity during the day has been determined. The Pontryagin function and the conjugate system of equations are written, taking into account the uneven distribution of material along the transport route.

According to the example of increasing the serviceability and reliability of the design of the parts of nuclear reactors from the zirconium alloy Zr1Nb due to the deposition of nanocoatings and the formation of nanostructures while they were bombarded with B+, C+, N+, Si+, Al+, V+, Cr+, O+, Fe+, Ni+, Co+, Y+, Zr+, Mo+, Hf+, Ta+, W+, Pt+ (with charge numbers 1, 2, 3) with energies of 200, 2000, 20000 eV the volume of grains and the minimum and maximum depth of their occurrence has been determined. This allows you to design the complex structure in depth, depending on the requirements for the reinforced layer. It is found that nanostructures are formed practically for all types of ions, except for boron and carbon, in the considered range of charge-number which ensures the reliability and performance of parts made of zirconium alloys.

The deflected mode problem for the structure composed of two glued coaxial cylindrical tubes under nonuniform longitudinal load is considered. The purpose of the paper is to obtain a mathematical model of a stress state that allows us to find an analytic solution to the problem. Pipes are considered as thick-walled rods, which are joined by a non-zero thickness adhesive layer. The tangent stresses in the glue are considered constant by the thickness of the adhesive layer. The tangent stresses in the adhesive layer are proportional to the difference of the longitudinal shifts of the tube sides, which are faced to the adhesive layer. The stresses in the pipes are considered to be constant in thickness, that is, in radial direction and dependent on the axial and circumferential coordinates. It is considered that the structural elements only move in the axial direction, i.e. the effects related to Poisson deformations are neglected. The deflected mode problem for the joint is reduced to a system of two partial differential equations relatively to longitudinal shifts of layers. The solution is obtaining using the classical variable separation method in the form of Fourier series by circumferential coordinate. The convergence of the solutions is proved. The model problem is solved, results are compared to calculations produced by the finite element method. The tangent stresses in the glue reach maximum values at the edges of the adhesive line. The mathematical model of the joint under certain constraints has a sufficient accuracy for engineering problems and can be used to solve structural design problems.

The paper presents a validation of the authors’ model of a bird-impactor for bird masses MB  = 0.7–3.65 kg, bird impact velocities VB = 100–200 m/s and impact angles α = 30–90°. Validation was performed by computations of bird impact with an obstacle by using a bird-impactor model and comparing computational data with available experimental data of bird impact field tests. The obstacles considered were steel plates: a weakly deformable (rigid) plate and a deformable plate. Computations were performed using the explicit LS-DYNA Solver. The bird-impactor model was validated for the load created on the rigid plate by using experimental research data of the Dayton Research Institute. The bird-impactor model was validated for plate strains by using data of experimental research at A. Podgorny Institute for Mechanical Engineering Problems of the National Academy of Sciences of Ukraine. Validation found that the bird-impactor model is capable of adequately reproducing impact loads acting like those as in the case of a strike by a real bird. This enables using the bird-impactor model for mathematical modelling of the processes of bird impact and of the damage to turbofan engine parts.

An improvement of the performance of modern heat engines is ensured through the use of new materials, design and technological solutions, and a higher level of modeling the processes that inherent in IC engines. Theoretical study and a pilot research prove that use of components with heat insulation layers on the surfaces that form the combustion chamber is one of the promising directions of integrated improvement of IC engines. It is achieved by means of increasing the amplitude of the combustion chamber surface temperature high-frequency fluctuations, at the time that the strength of the surface layer exceeds the one of the basic material. Under such conditions, it becomes possible to determine the reserves for further power increase of IC engines. The approach based on the principles of guaranteeing the structural strength is proposed that uses the results of mathematical simulation with the maximum reduction of design routes. It presupposes integration of the 1-D simulation method of the high-frequent temperature field of the surface layer of the structure in characteristic zones, the 3-D simulation of stationary temperature field and thermal stressed state of the structure, as well as the 0-D simulation of total fatigue and creep damage in the critical piston zone for a given cyclic change of engine load. The comparative analysis of the results for the piston of the tractor diesel engine is presented.

The ways of efficiency increase of the Francis type pump-turbines and widening of their operation range are considered. It is shown that one of the perspective ways is the usage of runners with additional shortened blades – splitters. Experimental studies of influence of the splitter geometric parameters on the energy performance of medium specific speed pump-turbines in turbine mode were conducted at the hydrodynamic test stand of A. Pidgorny Institute of Mechanical Engineering Problems NAS of Ukraine. The splitter length influence on the value of maximum efficiency, characteristics and parameters of the optimum mode is established. The simulation of the incompressible fluid viscous flow in the flow part is performed using authentic software package IPMFlow on the basis of numerical integration of Reynolds-averaged Navier-Stokes equations with an additional term that contains artificial compressibility. A two-parameter differential Menter’s SST turbulence model is applied to account the turbulent effects. The numerical integration of equations is performed using the implicit quasimonotone Godunov scheme with second order accuracy in space and time. Pressure distribution on the runner blades, comparison of the results of numerical and experimental studies are presented. The developed software package IPMFlow for the study of viscous compressible and incompressible fluid and gas flows, as well as the obtained results of the influence of geometrical parameters of the pump-turbine runner with splitters on energy characteristics can be used in the design and research of power machines for aviation and space technology.

It was found that the accuracy of the radial and circumferential non-uniformity modeling for the gas temperature pattern at the exit of the combustion chamber is unsatisfactory when using the k–ε turbulence model with the initial settings for the Ansys Fluent program. To reduce the non-uniformity of the temperature pattern at the exit of the combustion chamber, the degree of turbulent diffusion of gas components was increased with respect to the initial version of calculation, performed using the k–ε model of turbulence with the initial settings, by reducing the turbulent Schmidt number Sc. A numerical experiment was performed for the values of the Schmidt number Sc = 0.85 (default), Sc = 0.6, Sc = 0.4, and Sc = 0.2. The results of a numerical experiment confirmed the reductions of radial and circumferential non-uniformities with decreasing Sc, but theirs levels are different. Therefore, to ensure high accuracy in calculating both the circumferential and radial non-uniformities of the gas temperature pattern, it was proposed to use a variable value of Sc, depending on the gas temperature. The functional dependence of the turbulent Schmidt number Sc on the gas temperature was implemented in the Ansys Fluent program using the user function (UDF). The results of the gas temperature pattern modeling using the proposed UDF function for the turbulent Schmidt number Sc are in satisfactory agreement with the experimental data for both radial and circumferential non-uniformities of the gas temperature pattern at the exit of the combustion chamber.

The paper discusses simulation of the rotor dynamics phenomena in a power gas turbine unit (GTU) on the basis of numerical approaches and presents the results of a finite element analysis of the GTU rotor dynamics with identification of computational models based on incomplete data. They include parametric modeling and identification of the design finite element model of the rotor of a gas turbine unit in active magnetic bearings (AMBs) in terms of geometric and dynamic parameters. The parametric models of the gas turbine engine and generator rotors are created using beam finite elements. Depending on the section of the shaft line, the final element was assigned either with circular or annular cross-sections. Finite elements of an elastic connection were used for AMB modeling. The search for the geometric and physical parameters for the GTU rotor model was carried out in two stages – varying the geometric parameters and selecting the reduced properties of materials for individual sections. The criterion for the adequacy and suitability of the computational model for the further execution of various dynamic analyzes was the satisfaction of the known data (the values of natural frequencies and critical speeds, the amplitude-frequency characteristics of the entire GTU shaft line and isolated rotors). The results of the analysis of forced vibrations allowed verifying the models by the values of the resonance mode frequencies according to the data known from the open literature at the given parameters of imbalance and damping. Models are further suitable for computer-aided design using information technology.

This paper considers the issue of numeral estimating the residual strength of a centrifugal pump operating in excess of the design life in the line of pumps of the power station. Using modern technologies of computer and mathematical modeling the calculations of pump body for define its stress-strain state taking into account the change of geometry of body details had been carried out. The three-dimensional CE models are made, which take into account the actual geometry of the pump parts and the predict of its possible change for the period of extended time work. Estimation of static strength was performed for the main operating mode of the pump (under normal operating conditions). Taking into account the predicted values of the percentage of thinning of the wall of the pump, the statistical deformed state of the structure had been investigated. On the basis of statistical data, the parameter of damage and the probability of failure-free operation of the structure had been determined.

Computer modeling and solving of elements of gas-turbine engines allows taking into account the influence of various factors, and ensuring the reliable operation of the structure as a whole. The considered in this work dry gas seals are used as end seals in the gas-turbine engine-compressor system. This system is the main part of the gas-pumping unit, which maintains the required gas pressure in main gas pipelines. End seals are sufficiently important units, which ensure system tightness. The paper presents the developed specialized software package GasDin, which implements the proposed iterative algorithm for solving of interrelated gasdynamic, heat transfer and thermoelasticity problems for dry gas seals. The main part of this software package is the gasdynamic solution module, which makes it possible to obtain the gas pressure distribution in the gap between the rings taking into account the gas temperature changes. The developed software package GasDin also manages all stages of the iterative solution process. Testing of the developed software package took place in several stages for real designs of dry gas seals.

The efficiency of cooling the inlet air of the main ship diesel engine by a refrigeration ejector chiller (ECh) transforming the exhaust gas heat into the cold was analyzed for equatorial voyages. Refrigeration ECh is used as the most simple in design and reliable. However, the efficiency of converting the exhaust heat to cold by ECh is low: their coefficients of performance (COP) are 0.2–0.3, that requires a lot of available heat. The turbocompressor chillers (TCCh) are characterized by high COP of about 0.7 and comparatively small dimensions, that is of very importance for ship application. But because of high technology of their manufacturing nowadays they are quite expansive. The effect of cooling engine cyclic air was determined compared with engine without its cooling, taking into account the changing climatic conditions during the routes of the vessel. It is shown, that because of comparatively low COP the cooling capacity of ECh, produced by using the available exhaust gas heat, is not sufficient to cool the inlet air to a potentially possible minimum temperature of 15 °C when operating the ship engine in tropical climates. Meantime, due to high efficiency of TCCh they consume less exhaust heat than needed for cooling inlet air to 15 °C. An innovative combined cooling system is proposed that enables to use the excessive heat of exhaust gas, remained after TCCh, for subcooling air from 15 °C to 10 °C in ECh with gaining additional fuel saving.

The operation of the main ship diesel engines at high ambient temperatures are characterized by falling their fuel efficiency. In particular, the increased thermal loads on the engine cyclic air cooling systems are peculiar for tropical climatic conditions. This requires application of efficient waste heat recovery technologies. The cooling of the air at the inlet of engine by absorption lithium bromide chiller (ACh) is characterized by a high efficiency of transformation of waste heat into cold – by high coefficients of performance COP = 0.7–0.8. But the lowest temperature of air cooled by ACh of a simple cycle is limited by 15 °C, that is caused by a comparatively high temperature of its chilled water of about 7 °C. Meantime, the application of a refrigerant as a coolant enables deeper cooling air down to 10 °C and lower due to lower temperature of boiling refrigerant in intake air cooler. As alternative variant, the application of a refrigeration turboexpander chiller (TExpCh), characterized by a high COP of about 0.7 and comparatively small dimensions, that is very important for ship application, was investigated. The effect of cooling engine cyclic air for both ACh and TExpCh was estimated by fuel saving compared to the engine without intake air cooling and taking into account the changing climatic conditions during the vessel routes.

An approach to the study of heat exchange processes of the heat pump condenser circuit has been proposed. A mathematical model of the heat exchange process of the heat pump condenser circuit and the consumption line circuit has been constructed. The mathematical model is based on the equations of material and energy balances of the working fluid of the heat pump. Transfer function by the temperature of the freon in the condenser due to the regulating action of the temperature of the liquid of the consumption line has been constructed as well as the transfer function by the temperature in the consumption line due to the control action of the working fluid in the heat pump circuit. The transient responses for the freon temperature in the condenser and the temperature of the consumption line liquid have been obtained, respectively, and their research has been carried out with the help of simulation modeling. The transient responses of the studied circuits have been built. The results and graphs of transient processes and dynamic responses of the object have been given. It has been established that at lower consumption of liquid in the line of consumption the constant of time of transient process is of inertial character, and, therefore, in this case, the investigated conditions necessitate the increase of expenditures in the line of consumption, or in performance control of a compressor.

Complex cycles with cyclic air intercooling are used to increase the energy efficiency of gas turbines. A modern and widespread way to improve the cooling process is to humidify the working fluid (cyclic air). The efficiency of wet compression primarily depends on the intensity of evaporation and heat exchange of droplets with the air flow, which begins to increase sharply when the effective diameter of droplet spraying decreases to 20 μm. It is proposed to use a contact heat exchanger to obtain a finely dispersed flow of water in the flow path of a gas turbine. The operation of such contact heat exchanger called aerothermopressor was investigated in this paper. CFD simulation of the water droplet evaporation process in the aerothermopressor airflow was carried out. Calculations were carried out for three variants of evaporation of water injected into the air flow: complete evaporation of water droplets in the evaporation chamber, additional evaporation of water droplets in the diffuser and incomplete evaporation, with obtaining smaller droplets at the outlet of the aerothermopressor diffuser. Efficiency of the aerothermopressor application in the gas turbine circuit for contact cooling of cyclic air is analyzed. It has been revealed that the aerothermopressor allows increasing the cyclic air pressure between the compressor stages by 2–10%, which will lead to a decrease in the compression work in the compressor stages and makes it possible to increase the gas turbine engine efficiency by 1–2%.

The use of such techniques conflicts with the engine’s energy efficiency and leads to increasing fuel consumption. It is promising to use technologies that would increase fuel and energy efficiency of ICE with EGR systems and combine high environmental efficiency with engine fuel efficiency. The technology of precooling intake air at the suction of turbocharger by waste heat using chiller (WHUCh) was developed for ICE with EGR system. The scheme-design solution of the exhaust gas recirculation system with using the heat of recirculation gas by an ejector chiller for cooling the air at the intake of main ship engine is proposed. The scheme-design solution of the EGR system with using the heat of recir-culation gas by an ejector chiller (ECh) for cooling the air at the intake of main ship engine is proposed. The effect of using the heat of recirculation gas for cooling engine intake air is analyzed taking into account the changing climatic conditions on a vessel’s route line. It is shown that using the heat of recirculation gas for cooling engine intake air by ejector refrigeration machine reduces the air temperature at the entrance of the main engine by 5–15 °C, which decreases the specific fuel consumption by 0.5–1.5 g/ $$\rm{kW}\cdot \rm{h}$$ kW · h . This reduces emissions of harmful substances (NOx by 26–39%; SOx by 9–14%) when the engine is running with recirculation of gas.

The processing of ambient air by vapor compression and exhaust heat conversion refrigeration machines with heat removal from them to atmosphere by the circulating cooling systems are studied. Ambient air cooling is conducted by using different types of refrigeration machines: absorption lithium-bromide refrigeration machine (ARM), utilizing the exhaust gas heat of gas engine, combined absorption-ejector refrigeration machine (AERM) and electrically driven vapor compression refrigeration machine (VCRM). The data on current thermal loads on refrigeration machines of different types and their circulating cooling systems with dry cooling towers (air condensers in the case of VCRM) for different their project thermal loads were obtained through modelling their current loading in accordance with actual climatic conditions. The efficiency of performance of refrigeration machines of different types (ARM, combined AERM and VCRM) to provide the target temperatures of cooled air is estimated by annual production of refrigeration according to ambient air conditioning duties. It was shown, that the most energy-efficient refrigeration machine is the ARM, while the most energy-consuming was VCRM.

Developed in NAU “Kharkiv Aviation Institute” inverse magnetron sputtering system with sectioned cathode units and axial plasma flows allows to obtain multicomponent, multilayer and functional-gradient coatings. The advantage is shown over currently used technological ion-plasma generators. It is concluded that it is necessary to develop a mathematical model that allows one to calculate the operating parameters of the sputtering system. These parameters are to be known to obtain coatings of a given composition and thickness. It is shown that to solve this problem it is necessary to develop a numerical model for calculating the distribution of local plasma parameters in the discharge gap of an inverse magnetron sputtering system with sectioned cathode units and axial plasma flows. To solve this problem, a fluid plasma model was used. The distributions of the plasma potential, electron temperature and density in the discharge gap of the investigated sputtering system were obtained. Based on comparison of these calculated parameters with experimental data, the conclusion was made about the correctness of the developed mathematical model. Noted that in order to complete the development of a mathematical model for calculation the deposition rate and composition of the coating for an inverse magnetron sputtering system with sectioned cathode units and axial plasma flows, it is necessary to develop a mathematical model for calculating the distribution of the ion current density over the surface of the target cathodes and the energy of the bombarding cathode ions.

This work is aimed at studying material with a heterogeneous microstructure. The probabilistic characteristics of the yield surface are investigated. Statistically equivalent internal material structures are generated using computer simulations. The design takes into account the different amounts of spheroidal graphite inclusions concentration in the ferrite material. The stress state is calculated by the finite element method based on plane models. A series of experiments is calculated for each variant of the concentration of inclusions. The yield surfaces are determined. Based on the collected data, a study of the probabilistic characteristics of a random function is carried out. The radius function acts as a random variable. The number of intersections of the line with the yield surfaces is analyzed. The radii are constructed from the origin for each rotation angle along the closed circle. The proposed scheme takes into account the different behavior of composite materials under tensile and compressive loads. The probabilistic characteristics of the investigated quantity give a vision of the material operation modes at various loads. Going beyond the plasticity surface indicates the possibility of a product transition into a plastic state.

Despite the successful implementation of the Thermal Energy Method (‘TEM’), the issues of simultaneous cleaning of internal cavities and deburring remain unresolved. Moreover, the deposition of oxides on the surfaces of parts is inevitable. In contrast, Impulse Thermal Energy Method with Shock Waves (‘ITEMSW’) is devoid of these disadvantages. This is due to its capabilities such as generating shock waves with controlled frequency and intensity. In addition, it is possible to control the time of release of combustion products from the chamber. In the current work, the essential parameters of the efficiency of this processing method were investigated. The performed numerical studies present the influence of the intensity and duration of shock waves action on the magnitude of the heat flux acting in the chamber. It was estimated that in case of the shock waves generation, the magnitude of the heat flux turned out to be 20–50 times greater. It is practically impossible to achieve such an increase in the heat flux by increasing the initial pressure of the fuel mixture. Thus, the simulation results confirm that the controlled generation of shock waves is an effective way to increase the intensity of heat transfer during TEM treatment. Because of the fact that the distribution of heat fluxes over the surfaces of the workpieces with processing by ITEMSW significantly depends on the frequency of exposure to shock waves the problem of optimal parts layout was considered. It was estimated that the best uniformity of heat flux distribution under ITEMSW processing is provided by the sparest layout with balancing parts and zones of shock wave generation to the centroid of the inner surface of the working chamber.

Ramp and its units as one of the most important aggregates in the tail cargo door is reviewed. Such geometric parameters and units of the ramp as its maximum length Lp, the cutout in the ramp area, the theoretical line of the cargo door beam, the theoretical line of the ramp flooring, the ramp hinge units, its longitudinal and transverse beams, the ramp power locks, the ramp control cylinders and ramp rods, as well as the ramp sealing are presented. The main algorithms for determination are described using theoretical and practical data of most popular and used transport aircrafts such as An-124, An-26, Il-76, C-141, C-5 M. Most of presented information is collected considering time-tested best technical solutions as well as modern requirements of regulatory documents for transport category aircrafts (AP-25, CS-25, ICAO SRP A6, AC-25, OST).

The method of forming, finishing and shape refinement of ribbed panels by local deformation of the panel ribs using the rolling process is considered. The purpose of the article is experimental check of panel forming technology and shape changing accuracy under nominal and critical technical conditions of rib rolling of the monolithic panel as well as drawing up technical recommendations for using this method. In order to shape the profile and panel bending it is proposed to use the method that utilizes two rollers to deform areas of the rib. It provides the significant reduce in the angle of springing and expands the technological capabilities of the equipment. The process was simulated using FEM in the ANSYS software package for the case of oblique bending of ribbed panels. The problem of analyzing local stress-strain state during panel shaping was considered as quasi-static. The values of stresses and deflections of the panel sample at the point of load action and after removing the load were determined. It is shown on the example of aircraft wing panel oblique bending that the practical use of panel bending method with compression of ribs by rollers is expedient in case of sequential deforming the ribs with a counter and a passing sequence. The surface geometry along the axes of ribs that were bent by rollers shows better accuracy compared to the geometry of samples obtained by free bending in a punch. The results were compared to the data obtained by forming an aluminum alloy panel sample in unwinding device. It is shown that the method local forming by rolling allows achieving high accuracy of panel shape by means of correcting one-time impacts.

To model the kinetics of the thermal stress state in 3D structural elements with complex material properties, with account taken of plastic deformations, design features, and real loading conditions based on the finite-element method, a special calculation technique and software package have been developed. In this paper, the main relations of the developed calculation technique are presented and the main features of this technique are described. To study the stress-strain state of fuel tanks of launch vehicles, the software has been improved and upgraded. During the construction of different, in the degree of complexity and level of discretization, computational fine-element schemes, both the design and loading features of fuel tanks were taken into account. Calculation studies were performed based on data on the physical and mechanical properties of aluminum alloys and the corresponding strain diagrams. Calculations were performed with account taken of the internal and water pressures, the latter varying with the water level in the tank. The solution of elastic-plastic problems was carried out by the method of time steps with a given number of iterations in each of them. For different calculation models, values of plastic strains were obtained at fixed points of the tank. It was established that the results obtained by different calculation schemes are in good agreement with each other.

The paper considers the possibility of using short-wave (SW) band broadcasting stations to detect airborne objects using the Doppler method. It has been shown that detection is possible at Doppler frequencies are spaced from the carrier frequency up to 60 Hz. Air objects moving at speeds up to 2000 km/h have such Doppler shifts in the decameter wavelength band. The relation is given and the detection range of air objects is estimated, the requirements for the degree of suppression of the direct illuminating signal are determined. The spectral characteristics of the signals of HF broadcasting stations have been studied experimentally. Theoretical estimates of the RCS of air objects of various types at different polarizations are given, including airplanes are made using the Stealth technology. It has been experimentally confirmed that their RCS in the resonant region can reach thousands of square meters and exceed the values in the microwave band by 4…5 orders of magnitude. Noise levels in the Doppler band of detection have been determined and the detection ranges of airborne objects have been estimated. It is shown that if the illumination signal is suppressed by 30…40 dB, the detection ranges can exceed 200 km.

It is difficult to make decisions based on the large number of temporal and spatial signals received from physical, biological, chemical and other sensors. These signals differ in nature, dimension, complexity of form, etc., and the decision-making criteria are very diverse. The influence on the sensors reveals hidden features of functional characteristics. They create in information flows spatio-temporal inhomogeneities, the hidden nature of which is technologically or biologically inherited. Artifacts are observed in the sensor response-signals under extreme conditions, which indicate the fractal nature of the signals. Technological or biological heredity is inherent in all fractal objects and increases the risk of making erroneous decisions. The random nature of individuality finding required the development of a convergent approach based on 3D-modeling. For this, the means of processing, visualization and analysis of the dynamics of information flows are unified. They reveal the dynamic, energetic and informational characteristics of processes of different nature. This article describes the development of tools for modeling the dynamics of real processes of various natures that occur at different scale levels. This is relevant for solving the problems of the viability of the functioning of complex dynamic systems in abnormal conditions.

The search for parameters is carried out using stochastic optimization algorithms, namely, by the double annealing method. Self-heating simulation is based on finite element model of direct simulation of stationary heating of the specimen. The criterion for convergence of the optimization process is the data on the heating temperature obtained from field experiments. The verification of the reliability of the results is carried out by comparing the data on the area of the hysteresis loop obtained by numerical calculation and from a full-scale experiment. The paper presents the results of identification of the parameters of calculations of the thermal state, as well as the process of convergence of the search algorithm.

The relevance of project risk assessment has been analyzed. The processes of project risk management including process of planning a response to risk, which is substantial one, are described. It is proposed to carry out the selection of an optimal measures set for responding to risks using metoheuristic search methods. This search is a way to solve especially complex problems and is used in situations of significant lack of information. Two methods of metoheuristic search such as genetic algorithm and method of simulating annealing are considered. A feature of the genetic algorithm is the ability to simultaneously manipulate many parameters and generate new solutions through the utilization of crossing over and mutation operators. A feature of the simulated annealing method is the use of an ordered random search based on an analogy with the formation of a crystal structure in a substance, with a minimum energy upon cooling. It is chosen the project, which provides the minimum average duration in case of manifestation of risks, taking into account the assessment of their probability and consequences in the case of using a set of measures to respond to risks. The result is a vector whose length is equal to the number of risks planned in the analyzed project. Vector values correspond to one of the risk response options. The simulation is implemented using a computer program developed in the MATLAB system.

This paper is intended to provide an insight into the importance of project management success in implementing strategies and new financial packages within the context of university education. The discussion will call upon the universities to review and improve their strategies and detailed measures taking into account the international experience and the current situation. This paper builds up on the academic capitalism approach to show how universities can adapt to the new conditions simultaneously being under the continuous onward change processes in the context of Ukraine. The paper is structured as follows: first, it reveals the framework of the project management approach application in the university under the changing conditions with focus on the funding and financial aspect. Second, it investigates the domestic and international experience of responding to the challenges of the COVID-19 pandemic by the universities. It's worth noting that this paper provides an important source to analyze different types of support for solving problems of higher education institutions and students during challenging times.

An urgent scientific problem is the development of methodological foundations of human resource management in a multiproject environment. The aim of this research is to create tools for managing human resources in a multproject environment. The following tasks are solved in the article: to develop a method for analyzing the coherence of human resource management strategies in a multiproject environment; analyze the causes of changes and their impact on human resource management processes; build a model of the process of redistribution of resources; develop tools for team building and reallocation of resources in a multiproject environment. In the study, methods of system analysis, the apparatus of the theory of optimization, Boolean algebra and set theory were used to solve the problems of team formation and redistribution of resources. An analysis of the literature on resource management. A method for analyzing the consistency of human resource management strategies in a multiproject environment has been developed. The analysis of the causes of changes in projects and their impact on the processes of managing human resources is carried out. The application of the donor-acceptor approach to resource support in a multiproject environment is considered. A model of the process of reallocation of resources is proposed. Tools were developed for team building and redistribution of resources in a multi-project environment.

Knowledge management plays significant role in company innovation processes since idea generation and solution development depend on knowledge and experience not available up to date. Therefore, main focus of this research is to improve effectiveness of employee knowledge management in IT company by creating appropriate learning content for personnel training. In order to accelerate that process and decrease effort necessary, we propose an approach for automatic content import from Knowledge Management System (KMS) into Learning Management System (LMS). The article includes a survey of recent approaches to knowledge management in the context of organizing e-learning process in a company. Moreover, for task of content import it was necessary to overview modern e-learning standards with their pros and cons taking into account our research goals. As a result, we have selected SCORM standard, which serves as a basis for software component and consequently decreases time for learning content creation and import.

The problems of integration for systems of strategic, tactical, operational planning and budgeting into a single company planning system were analyzed. The company which uses process management and Balanced Scorecard (BSC) to create a Key Performance Indicators (KPIs) system, is considered. The structure of the cascading subsystem for strategic map and BSC is proposed as part of the Enterprise Performance Management System which is being implemented at the company to automate strategic management processes. The cascading method is suggested which is implemented in the process of developing a strategic program for company growth. Strategic KPIs are formed based on the strategic map. Further, these indicators are cascaded in three strategic aspects: by business processes; by company divisions; by planning levels: strategic, tactical and operational (level of budgets). Business processes are considered for the main, investment and financial activities. As a result of the cascading process, the KPIs system is built and the planned values of the strategic KPIs, KPIs over the years for the strategic period and the indicators of the company’s strategic budgets are determined. This is the basis for the developing of strategic, tactical, operational plans and strategic budgets of the company and its divisions. This method allows to carry out strategic alignment in the company, coordinate the strategic goals of the company and its divisions, and harmonize the plans of the company and divisions in terms of process management.

The study examines the pedagogical conditions for the use of information and communication technologies in the process of professional training of students of mathematical specialties. It is proved that the use of information and communication technologies in the educational process makes it possible to increase the indicators of the formation of students’ professional competence. The analysis of the results of experimental studies made it possible to draw a conclusion about the advisability of using information and communication technologies for the formation of professional competence of students of mathematical specialties.

Discussion questions about the ethical nature and legal regulation have always been an integral part of the rapid development of information technology, robotics and artificial intelligence. Innovation will inevitably lead to social and legal changes, which can cause some difficulties for both business and countries, as well as for individuals. In the paper, we tried to highlight the trends and give an overview of the most common socio-legal issues that the Industry 4.0 concept raises. Working with extra-large amounts of data, machine learning, Internet of things and cloud storage each year increase the number of violations in the field of storage, use and transmission of data. This causes tension in society and creates people's distrust of technology. Also, intellectual property law receives new challenges related to the participation of artificial intelligence in the creation of intellectual property. Robots and artificial intelligence significantly change the labor market and compete with people in the field of employment. Studies and statistical indicators in these areas were examined, on the basis of which was concluded that it is necessary to develop standards and areas for further work.