Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines最新文献

{"title":"Dynamic analysis of functional gradient porous sigmoidal sandwich plates","authors":"Iryna Morachkovska, L. Kurpa, A. Linnik, G. Timchenko, T. Shmatko","doi":"10.20998/2078-9130.2023.1.281191","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.281191","url":null,"abstract":"Analysis of free vibrations of functionally graded (FG) porous sigmoid sandwich plates, is considered in this paper. The plate can have a complex geometric shape and various types of fastening. To solve the problem, we used the variational-structural method (RFM), which combines the theory of R-functions and variational method of Rayleigh-Ritz. The mathematical statement of the problem is carried out within the framework of the deformation theory of plates of the first order (FSDT). Plates are considered, the outer layers of which are made of functionally graded materials (FGM), and the core is isotropic. For different models of porosity distribution (sigmoid uniform and nonuniform), analytical expressions were obtained to calculate the effective properties of FGM. For rectangular plates, a comparison of the obtained results with known results obtained using other approaches is shown. Calculations for plates with a complex shape are presented in the form of tables and graphs. The influence of the volume fraction of ceramics, the different types Of FGM  and the coefficient of porosity on the natural frequencies of the plate is analyzed.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138952680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and computer implementation of the motion model and control algorithms of a hybrid multicopter","authors":"Valerii Uspenskyi, Serhii Harder","doi":"10.20998/2078-9130.2022.1.263784","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.263784","url":null,"abstract":"Among modern unmanned aerial vehicles, a special place is occupied by hybrid multicopters, in which internalcombustion engines are used along with electric motors to create lift. They can carry a larger load for a longertime. But the combination of a more powerful engine with less powerful ones, the variability of the inertialcharacteristics during the flight, significantly complicate the dynamics of such an object and its control. Therefore,there is almost no practical experience in operating such devices, which is the motivation for research anddevelopment in this area. The article deals with a helicopter-type multicopter with five electric motors (4+1 on thetail) and a central internal combustion engine. A mathematical description of the dynamics and kinematics of the \u0000apparatus has been created for the purpose of computer simulation of a controlled flight. The description takes intoaccount all internal dynamic factors and is given simultaneously with respect to the inertial and associatedcoordinate systems, which simplifies the solution of the flight control problem as much as possible. For the latter, amultiloop motion control scheme with the help of motors has been developed. The algorithms are based on thedecomposition of the problem under the conditions of typical motion modes and the modal control method, whichprovides the desired quality of transient processes. A universal automaton for the interaction of control algorithmsfor each engine is described. A typical flight program is simulated, containing climb, course change, following tothe set hovering point and landing under it. The presented results showed the performance of the algorithms anddetermined the directions for further research. The results in the form of a mathematical model, recommendationsfor task decomposition and specific algorithms can be used in the process of designing a hybrid multicopter controlsystem.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127222064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear bending of polygonal functionally graded plates resting on elastic foundation","authors":"Iryna Morachkovska, L. Kurpa, Kateryna Liubytska, A. Linnik","doi":"10.20998/2078-9130.2022.1.263808","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.263808","url":null,"abstract":"To investigate nonlinear bending of the functionally graded (FGM) plates with complex shape and resting on elastic foundation a variational-structural method (RFM) is proposed. Mathematical statement of nonlinear boundary value problems of plate bending is carried out in the framework of the classical geometrically nonlinear plate theory. To solve a sequence of linear boundary value problems obtained as a result of the linearization of the original nonlinear system of equations by the method of successive loadings and the Newton method, the method of R-functions was applied. Testing, as well as comparison of the obtained results with the results of other authors, made it possible to establish the reliability and effectiveness of the developed approach and apply it to study the stress-strain state (SSS) of thin plates with complex shape. A computational experiment was carried out for thin hexagonal plates with mixed boundary conditions for various types of external load and elastic foundation characteristics. The relationship between the greatest deflection of the plate and the load is obtained. The results are presented in the form of graphs.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"179 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116418919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational approach to thermal-stressed state modeling of tire based on the algorithm of its self-heating analysis . Part 1 – Theoretical basics of the approach","authors":"Y. Viazovychenko, O. Larin","doi":"10.20998/2078-9130.2022.2.270935","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.2.270935","url":null,"abstract":"Elastomers and their composites are widely used in modern innovative technology: for the production of aviation and automobile tires, anti-vibration elements (rubber, rubber-metal springs), dampers, elastomeric bearings. Also they are used in shaft suspensions, as spacers between structural parts, supporting parts and fasteners. Elastomeric elements of structures have a high dynamic load, in particular of a cyclic nature, which is accompanied by the formation of hysteresis loops and, as a result, the occurrence of the phenomenon of self-heating. An increase in temperature in the middle of materials causes significant changes in their mechanical properties, reduces strength characteristics, accelerates aging and degradation processes, and has a significant impact on fatigue processes. In addition, an increase in temperature causes an additional thermal stress state, capable of significantly changing the qualitative picture of the structure's deformation characteristics' distribution. Thus, the purpose of this study is development of approach to assessing the thermal stress state of structures made of elastomeric materials for the possibility of further analysis of its influence on the structure work as a whole. The appropriate approach was built on the basis of numerical modeling of thermal and deformation processes which takes place into the structure during operation. The proposed approach includes several related calculations by using FEM and is based on the fundamental approaches of the theories of elasticity and viscoelasticity, thermal conductivity and thermo-elasticity. Thus, the article presents an approach to the analysis of the thermal stress state of structural elements under operating conditions. This approach was applied to determine the thermo-strain-stress characteristics of a pneumatic tire and corresponding pictures of its distribution were obtained.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116539750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive approach to the analysis of the static and dynamic strength of the rotor of the smoke cleaner","authors":"V. Martynenko","doi":"10.20998/2078-9130.2022.1.264326","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.264326","url":null,"abstract":"The work describes the process of assessing the static and dynamic strength of the rotor of an axial smoke exhauster with twin blades which allow significantly increasing its efficiency. To build a calculation model for the strength analysis, the geometric model was simplified by removing bolted connections, slicing small surfaces, as well as modeling welds in the form of roundings and chamfers. Such simplifications made it possible to build a high-quality finite-element mesh with the sufficient accuracy for performing engineering calculations. Calculation models include a finite-element model of one sector of cyclic symmetry of the impeller of the smoke exhauster, which is used to more accurately determine its stress-strain state and local maximum stresses in the places of their concentration in the root sections of the blades and in the places where they are connected by jumpers due to the action of centrifugal forces, aerodynamic loads on the blade and thermal loads due to wheel heating, as well as a finite-element model of the entire rotor with a less detailed meshing of the impeller, which in this case plays the role of a mass-inertia element, and a more detailed meshing of the shaft to analyze its static strength and reactions in bearing assemblies from the action of gravity and determine natural frequencies and mode shapes of rotor vibrations and the possibility of resonances with multiples of the frequency of excitating loads. The analysis of the static strength of the impeller and the rotor shaft of the smoke exhauster was performed by comparing the von Mises equivalent stresses with the allowable stresses, and the analysis of the dynamic strength of the smoke exhauster rotor was performed by determining the level of detuning of the natural frequencies of vibrations from multiples of the frequency of the excitating load, which in this case was assumed to be the centrifugal forces acting on the unbalance of the rotating rotor. A detailed analysis of the results of calculations made it possible to establish that the elements of the smoke exhauster rotor meet the requirements of static strength under the action of all possible types of loads, and the natural frequencies of the rotor oscillations have a sufficient level of detuning from multiples of the frequency of the excitating load. In this way, a conclusion was made about the static and dynamic strength of the rotor of the smoke exhauster, which affect its resource and durability of operation in the nominal mode.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126919411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Static analysis of multi-support stepped spindle shafts with nonlinear elastic bearings","authors":"Valerij Havin, O. Kyrkach, B. Kyrkach","doi":"10.20998/2078-9130.2022.2.270866","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.2.270866","url":null,"abstract":"In this paper a mathematical model and a computational technique for the static analysis of multi-support stepped spindle shafts on nonlinear elastic supports are presented. On the basis of the Timoshenko differential equation of the beam's bent axis and the method of initial parameters, a resolving system of equations is obtained that takes into account the nonlinear dependency of the stiffness of the bearings on the forces acting on them along with the stepwise variation of the cross-sectional dimensions of the shaft. A numerical method for solving the problem has been proposed and a software tool has been developed, which performs the static analysis of multi-support stepped spindle shafts on nonlinear elastic supports in MATLAB environment.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131494505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of the thermal regime of a platformless navigation system with thermal stabilization of accelerated warm-up","authors":"Sergij Yurijovich Pogorilov, Valerij Khavin","doi":"10.20998/2078-9130.2022.1.265440","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.265440","url":null,"abstract":"Currently, platformless inertial navigation systems (IBS) based on fiber optic gyroscopes (FOG) are widely used in modern aviation and space technology. In connection with the high sensitivity of VOG to the influence of temperature changes, ensuring stable thermal modes of operation is an urgent problem. The most important task of increasing the accuracy of system operation is the development of methods of thermal protection and thermostabilization of VOG. The work is devoted to the modeling of the temperature field of the platformless inertial unit (BIB), which is part of the BINS, in order to ensure a minimum temperature difference on the VOG platform with the use of thermal stabilization. The purpose of the work is to simulate the temperature field of the BIB measuring unit and determine the conditions that ensure a minimum of temperature differences on the VOG platform under thermal stabilization conditions. To achieve the goal, the following tasks were solved: creation of a calculation scheme and finite element model of the BIB device, modeling of the effect of changes in external temperatures on the temperature field of the BIB device, numerical determination of temperature gradients at given points of the device. According to the results of numerical modeling, the parameters of the temperature field of the device and the characteristics of the thermal stabilization system were studied. The thermal mode of the device with a thermostabilization system for accelerated heating and reduction of temperature change gradients on VOG sensors with a governing law corresponding to base temperature changes is considered. The temperature gradients at the given points of the device are numerically determined. It was established that the law of thermostabilization should ensure the stability of the temperature field (the smallness of the temperature gradient). The value of the VOG temperature itself does not have a significant effect on the amount of drift. It is advisable to use the thermal stabilization system only to bring the system to the working temperature mode for no more than 30 minutes, and not to use it in the working mode.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130819744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computer modeling of the stress state and reliability assessment of bolted connections of the rotor and runner of Kaplan turbines","authors":"O. Vodka, Y. Viazovychenko, O. Larin, K. Potopalska","doi":"10.20998/2078-9130.2022.2.271065","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.2.271065","url":null,"abstract":"Ensuring the trouble-free operation of hydroelectric power stations is an important element of the stability of the power grid. Hydraulic turbines are often used to regulate daily fluctuations in electricity consumption. It is the start/stop modes of the hydraulic unit that are the most dangerous and lead to the highest levels of mechanical stress. Therefore, the work is devoted to the development of detailed three-dimensional models for assessing the stress state of bolted connections of the impeller, and on their basis determining the stress state in different operating modes of the hydraulic unit. The similarity method based on known experimental data is used to determine the load acting on the bolted connection. Determination of the stress state is carried out using the finite element method. The developed three-dimensional detailed finite-element model takes into account the non-linear interaction between the connecting parts: the bolt, the shaft flange, and the impeller body. Determined stresses as a function of time, which occur during the start/stop of the hydraulic unit and are used to estimate the life (including the residual) of the bolted connection.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126191814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact on the beam of the final length of the moving mass","authors":"Andriy Sharapata, S. Povalyaev, Yevgen Yanyutin","doi":"10.20998/2078-9130.2022.1.263348","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.263348","url":null,"abstract":"There have been considered solving direct problem of deforming of isotropic, elastic and hingedly supported beam of finite length. A roller moving at a constant speed along the axis of the beam acts on the beam. The roller has a cylindrical shape of a certain radius and a length that is greater than or equal to the width of the beam. The differential equations of beam motion are analyzed from the point of view of the influence of their components and especially the right-hand parts of the equations on the dynamic behavior of the beam in the case of using certain common materials of the beam and roller, and an option to reduce the equations to a more simplified form is proposed. The unknown functions included in the equations are sought in the form of Fourier series. This allows us to reduce the original equations to ordinary differential equations, which are solved using the Laplace transform. Expressions for coefficients in Fourier series are found using operational calculus and the residue theory. The results of the first numerical experiment on the study of the influence of the roller speed on beam deflections are presented in the form of curves in the figure. For a specific calculated mechanical system in the form of a steel roller, which moves along a steel beam at a constant speed under zero initial conditions, the research results are presented in the form of graphs of beam deflections for different speeds of the roller. The second numerical experiment was carried out to study the propagation of vibrational waves of the beam in the case of motion of the roller at a sufficiently high speed. For this, the figure shows the combined shapes of the beam and the position of the roller at different moments of action of the moving mass. The behavior of the beam at a high speed of movement of the roller was analyzed and a comparison of the deflections of the beam with the deflections of the static model of the beam was made. Further directions for the development of the problem in applied fields of technology and in inverse problems of identifying unknown parameters by indirect manifestations are outlined.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134113906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional representative volumetric elements for the construction of composite materials with improved mechanical properties","authors":"Kyryl Degtyariov, D. Kriutchenko, S. Misura, A. Merkulova, D. Merkulov, Євгенія Місюра","doi":"10.20998/2078-9130.2022.1.263930","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.263930","url":null,"abstract":"A methodological and software tool was developed for the effective assessment of the properties of three-dimensional composites of the matrix type and periodically structured composite materials using modern methods of boundary and finite elements. Continuum mechanics models have been modified to adequately describe the behavior of composites, numerical simulation models and software have been adapted to these models for solving static problems and problems in the frequency domain. The novelty, advantages and efficiency of the developed computer technology are provided by theoretically grounded models for the analysis of composites of three-dimensional configuration with non-canonical particle shapes, improvement of modern boundary and finite element methods and coupled algorithmic schemes to achieve high accuracy of calculation analysis; suitability for the analysis of both static and dynamic elastic fields in the considered structures. Calculation models and software tools have been developed that allow to take into account special forms of individual and interacting inhomogeneities in a three-dimensional matrix, in particular, with an emphasis on short fibers and tubes. These models and methods are applied to the study of static and dynamic characteristics of launch vehicle tanks made of various composite materials. For the studying free and forced oscillations of shell structures with compartments containing liquid, the method of natural modes  has been developed. Composites with an aluminum matrix with steel spherical inclusions and with steel and carbon fiber inclusions were considered as tank materials. The proposed models and computer simulation algorithms allow to carry out the numerical analysis of three-dimensional static problems under classical conditions of contact with the matrix; three-dimensional problems regarding the static interaction of a finite number of inclusions in the matrix; research of ordered and stochastically distributed inclusions; study of inclusions in the form of spheres, cylinders, carbon tubes and inclusions in the form of hollow spheres and to determine the effective elastic parameters of three-dimensional matrix composites with spherical inclusions, fibers and tubes. The results of the calculations showed strengthening of the obtained composite materials with a simultaneous decrease in density","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134338921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}