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

{"title":"Analysis of a crack with finite electrical permeability between two piezoelectric materials","authors":"Maksym Levchenko, Volodymyr Loboda","doi":"10.20998/2078-9130.2023.1.275582","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.275582","url":null,"abstract":"A crack with finite electrical permeability between two piezoelectric materials is investigated. Initially, it is believed that the length of the crack is much smaller than the size of the body, so the latter is considered infinitely large. Assuming that the electric flux through the crack does not change along its length, an analytical solution to the given problem is constructed. On the base of this solution the magnitude of the electric flux, as well as other components of the electromechanical fields are found. A fairly simple formula for the energy release rate (EER) is also derived. For some values of the electrical permeability of the crack medium and external loads, the amount of electric flow through the crack and EER are calculated. Approbation of the obtained results was carried out on the example of a similar problem, but for the domain of finite dimensions. The finite element method (FEM) was used and the inverse approach was applied. According to this approach, the electric flux through the crack, which is obtained analytically, is used, and the solution is carried out using FEM. The analysis of the obtained numerical results confirmed the reliability of the methodology and the obtained analytical solution. \u0000Keywords: crack with finite electrical permeability; piezoelectric bimaterial; analytical solution; finite element method.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"31 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138949697","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":"Сomputational approach to thermal-stressed state modeling of tire based on the algorithm of its self-heating analysis. Part 2 – Practical results of applying the approach","authors":"Iuliia Vyzovichenko, Oleksiy Larin","doi":"10.20998/2078-9130.2023.2.293683","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.293683","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":"59 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138950899","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":"Using methods of probability theory and mathematical statistics in project management","authors":"Mariіa Nekrasova","doi":"10.20998/2078-9130.2023.2.293040","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.293040","url":null,"abstract":"The place of methods of probability theory and mathematical statistics in the system of general scientific methods of project management is shown. The composition of the main methods of probability theory and mathematical statistics, most in demand in project management, is briefly described. The role of the Monte Carlo method is also noted, because it is designed to take risk into account in the process of quantitative analysis of project characteristics and management decision-making. The possibilities of project management are shown, which provide the methods of probability theory and mathematical statistics in project management from the Project Management Body of Knowledge (PMBoK) methodology. It is shown that the methods of probability theory and mathematical statistics in project management from the PMBoK methodology are most needed in the implementation of the following groups of project management processes: a group of project planning processes, a group of project monitoring and management processes. \u0000Keywords: methods, probability theory, mathematical statistics, project management \u0000  \u0000  \u0000 ","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"51 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138949891","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":"Autonomous method for a strapdown inertial navigation system calibration in operation in operation","authors":"Valerii Uspenskyi","doi":"10.20998/2078-9130.2023.1.273074","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.273074","url":null,"abstract":"Strapdown inertial navigation systems (SINS) are widely used in modern air transport. The service life of such systems is decades. During this time, the characteristics of such systems may deteriorate due to the degradation of inertial sensors - gyroscopes and accelerometers. Under these conditions, in order to maintain the required accuracy of the SINS during the entire period of operation, it is necessary either to periodically carry out routine maintenance with the onboard system, or to continuously adapt the used sensor measurement model in terms of compensating for errors that arise. The second direction, which we will call calibration, has the advantage over the first one that it is carried out automatically by the system itself and does not require any additional equipment or additional maintenance work. The known method of SINS recalibration is based on the integration of information from the SINS and from the receiver of satellite radio navigation signals (SRNS). Such calibration, firstly, significantly depends on the availability and quality of satellite information, and secondly, it is possible only for integrated navigation systems in which the inertial subsystem is supplemented by a SRNS receiver. In contrast to the known method, this article solves the problem of autonomous SINS calibration, which is carried out after each flight. The solution is based on a linearized inertial navigation error model based on the boundary conditions of the state vector (at the beginning and end of the flight). The external information used consists only of the initial values of the coordinates and the current measurements of the baroaltimeter. As a result of the decision at the end of the flight, the errors of gyroscopes and accelerometers are determined, as well as the error in determining the final values of latitude and longitude in the SINS. Sensor errors can be used in subsequent system activations, which improves the accuracy of its operation as a whole. The analysis of the suitability and effectiveness of the developed methodology was carried out on a typical flight simulation program.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"53 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138952395","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":"Software for processing of long-term strength data of materials by use of edwards curves","authors":"D. Breslavsky, Andriy Khoroshun, A. Senko, Oksana Tatarinova","doi":"10.20998/2078-9130.2023.2.292955","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.292955","url":null,"abstract":"A description of the developed software for saving and analyzing data on high-temperature deformation and long-term strength of metallic materials is provided. The open source Laravel web framework was chosen to implement in the application. The Voyager solution is used together with it as a graphical interface for interacting with the database. A JavaScript programming language solution using Canvas technology is used to build plots. Basic classes and components are described. With the help of diagrams of use cases, the possibility of using the web application in the engineering practice of data processing of experimental high-temperature creep and fracture studies is shown. An approach and an algorithm for approximating long-term strength curves of general appearance, including different types of failure, using Edwards curves are proposed. With their use, an analytical nonlinear expression for the functional dependence between the time to failure and the failure stress was obtained. Approximations of various types of the long-term strength curve corresponding to the processes of accumulation of damage in the material by various types of physical mechanisms are discussed. The undesirable possibility of obtaining an overestimated value of the time to failure in the case of small and medium stress values without using information on the areas of intergranular failure, failure due to oxidation or corrosion, and overaging on the long-term strength curve is demonstrated. The use of the developed software, approach and method of analytical representation of the functional dependence of the values of failure stress on time in the evolution equation for the damage parameter allows you to carry out refined calculations of structural elements operating under high-temperature load conditions","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"54 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138949771","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":"Orientation Quaternion Norm Correction in SINS Algorithms: Calculation Normalization Schemes and Their Efficiency","authors":"Yu A Plaksiy","doi":"10.20998/2078-9130.2023.1.284852","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.284852","url":null,"abstract":"The problem of correcting the norm of the computed orientation quaternion in the algorithms for the operation of strapdown inertial navigation systems is considered. Two existing approaches to the correction process are considered, the first approach is to normalize the rotation quaternion at the computation cycle, the second approach is to normalize the resulting quaternion. 5 well-known calculation schemes for norm correction are given. To simulate the test motion, we used an analytical quaternion kinematic rotation model based on a sequence of three rotations corresponding to the Krylov angles. The case of linear dependence of elementary rotation angles on time is considered. The model provides analytical representation of the projections of the angular velocity vector of the rigid body on the associated axes and the corresponding quasi-coordinates on the calculation cycle. The results of numerical simulation of the reference motion for a given set of frequencies are presented as dependences of the projections of the angular velocity vector of the rigid body on time and the constructed trajectories in the configuration space of the orientation parameters. \u0000To determine the rotation quaternion on a cycle, the Miller algorithm was used, which makes it possible to obtain an increase in the orientation vector based on ideal information from the angular velocity sensors in the form of quasi-coordinates. The transformation into a rotation quaternion occurs with the help of the corresponding expansions of the trigonometric functions of the true rotation angle (modulus of the orientation vector) in a series. \u0000Based on a numerical experiment, it is shown that the best result of correcting the norm of the calculated quaternion in the sense of the minimum error of the norm is given by one of the finite normalization schemes, for which there is no division operation and ensures the stability of the norm correction in time. The results of numerical simulation of the model rotational motion of a rigid body and the development of schemes for correcting the norm of the calculated orientation quaternion are presented. \u0000Keywords: orientation quaternion, Miller's orientation algorithm, SINS, norm error, computational drift, analytical reference model, quasi-coordinates, numerical simulation.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"28 25","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138950316","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":"Algorithmical determination of the equilibrium/stead position of a dynamic system by the finite-step method","authors":"Yu A Plaksiy","doi":"10.20998/2078-9130.2023.1.277161","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.277161","url":null,"abstract":"The problem of algorithmic estimation of the equilibrium/stationary  state of the dynamic system based on the minimum number of measurements of  the output quantity at equidistant time points is considered. For this, a finite-step method was used, which consists in the formation, according to certain rules, of the sums and differences of the values of the output quantity, which are located symmetrically on the time axis relative to a certain moment that can  be determined a priori. As a result, overdetermined systems of  linear equations are formed with respect to the introduced fictitious unknowns, and based  on the necessary condition for the existence of a solution to these systems, formulas are found to determine the equilibrium/stationary  position  of  the dynamic system. Algorithms for determining the equilibrium /stationary  state for the following mathematical models of the output value are given: in the form of a constant component and a damped  exponent, in the form of a constant component and a damped sinusoid, in the form of a constant component and two undamped sinusoids, in the form of a constant component and a damped sinusoid. It is shown that in the absence of  measurement errors of the output value, the error in estimating the equilibrium/stationary  state of  the transient process depends only on the error in solving the system of  linear equations. Ways of using the redundant number of measurements are discussed. \u0000Keywords: equilibrium position, stationary state, dynamic system, mathematical model, finite-step method, numerical algorithm.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"90 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138994153","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":"Thermosensitive generators based on single-junction and field-effect transistors","authors":"P. Markolenko, L. Vikulina, Ivan Vikulin, Oleksandr Nazarenko","doi":"10.20998/2078-9130.2023.1.274466","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.274466","url":null,"abstract":"The effect of temperature on the characteristics of generators based on a single-junction transistor (SNT) was experimentally investigated. It is shown that when using an OPT generator as a sensor with a frequency output, field-effect transistors are inserted into the circuit of the OPT emitter and base to increase the dependence of the frequency on the temperature. To obtain a direct dependence of the frequency on the temperature, a field-effect MDN transistor is introduced into the emitter circuit of the OPT, and to obtain an inverse dependence, a field-effect transistor with a p-n junction is used as a gate. The maximum sensitivity with a direct dependence is achieved when an MDN transistor is included in the emitter circuit of the OPT, and a transistor with a p-n junction is included in the base circuit. The influence of radiation on the thermal sensitivity of generators was investigated. The component transistors were irradiated with a stream of electrons, γ-quanta and neutrons. It was established that the irradiation of each transistor affects the output frequency of the generator differently, it either decreases or increases. It is shown that using transistors with the opposite sign of the generator frequency change during radiation, it is possible to reduce the dependence of the output frequency on radiation. The maximum compensation of the effect of radiation on the output signal can be obtained when using an MDN transistor in the emitter circuit of the OPT, and a transistor with a p-n junction in the base circuit. Limit values of flows of various radiations, after which the generator stops working, have been established.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"27 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138948193","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":"Numerical and experimental study of the conical connection of the blade of a rotary machine","authors":"Volodymyr Martynenko","doi":"10.20998/2078-9130.2023.1.284029","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.284029","url":null,"abstract":"The paper presents an experimental and numerical study of the tapered socket of the aluminum blade root of the mine main ventilation fan, which is based on the tests of a simplified full-scale model with a discarded airfoil and its subsequent finite element analysis. The calculation model takes into account elastoplastic properties of materials and non-linear contacts with friction. The proposed joint consists of an aluminum tapered blade root, two steel retainers with similar tapered surfaces, and two steel bolts that join the retainers around the root. Pre-tightening the bolts allows fixing the blade in an unloaded state in the socket and prevents its unwanted turns. Such a tightening is taken into account in the finite element analysis by means of determining, in compliance with special rules, the axial force of the pretension of the bolts. With the help of a hydraulic press acting on the lower surface of the airfoil root, the effect of the centrifugal load on the conical joint from the side of the blade airfoil is simulated. Nonlinear static analysis of the elastoplastic behavior of the structure allows determining the destructive loads that cause the bolts to break with the subsequent disconnection of the fasteners and the blade to fly out of the seat. The graphs of the equivalent von Mises stresses indicate that the maximum stresses are reached in the working part of the bolts, which fully corresponds to the nature of the destruction of the structure upon reaching the maximum equivalent load on it. The experimental study confirms the correctness of the determination of contact stresses at the tapered socket location. Correspondence of the results of the static analysis with the results of the full-scale experiment makes it possible to draw a conclusion about the correctness of the conducted finite element modelling. This allows using the developed formulation of the problem to determine the strength of rotor structures with conical connections of blades without performing preliminary experimental studies. In addition, the developed technique can be extended to a larger range of conical and cylindrical joints due to the simplicity of the approach and the versatility of the formulation of the nonlinear finite-element problem which models structures with preloaded or tensioned elements.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"47 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138949001","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 of a mobile application for checking the level of English knowledge using the SWIFT programming language and the UIKIT framework","authors":"Daria Krasulia, K. Ivanchenko, Dmytro Ivanchenko","doi":"10.20998/2078-9130.2023.2.293692","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.293692","url":null,"abstract":"This scientific work is aimed at the development and implementation of an innovative mobile application aimed at assessing the level of knowledge of foreign languages. The main goal of the study was to create a convenient and fast tool that allows users not only to determine their level of language competence, but also to identify shortcomings and determine the optimal path for further improvement. \u0000In the course of the study, the existing methods and systems for evaluating language skills were carefully analyzed. Based on this analysis, detailed functional and non-functional requirements for the developed software product were formulated. The choice of technical and software tools, in particular the Swift programming language and the IOS operating system, was justified by their relevance and the ability to create applications for all devices in the Apple ecosystem. \u0000A significant part of the work was the creation of a database using the non-relational Realm system for mobile devices. The application interacts with data in JSON format, which allows you to efficiently load and display lists of questions for users. In the development process, such libraries as Foundation, UIKit, RealmSwift and others were used in order to ensure optimal performance and reliability of the application. \u0000Special attention was paid to creating an intuitive and convenient interface for users. The development process included a careful design of the logic and structure of the mobile application in order to ensure maximum convenience during use. \u0000One of the key parts of the research was testing the developed application. UI testing was carried out to check the correctness and usability of the interface, compatibility testing to ensure operation on different devices, and functional testing to check compliance with all defined requirements. \u0000As a result of the research, an information system for automated testing that meets high standards and requirements was successfully developed. The obtained results can serve as a basis for the integration of the program into the educational process or to provide students with the opportunity to gain practical skills in assessing their language competence.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"35 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138950025","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}