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

{"title":"Modern algorithm of linear and quadratic programming in optimization and problems of deformation of structures of variable structure in contact conditions","authors":"V. Grischenko","doi":"10.20998/2078-9130.2023.2.293695","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.293695","url":null,"abstract":"Various mathematical problems, in which the goal of finding the extremum of a functional is set, belong to the problems of mathematical programming and optimization problems. Practically directed problems of finding the optimal solution are extremely numerous in economics, management, technology, and others. They are related to increasing production efficiency, reducing resource costs, improving design solutions and technological processes, reducing mass, dimensions, etc. Among them, an important role is given to the methods of limiting the maximum stresses caused by external loads. Solving such problems begins with mathematical formalization. Constructive, economic or technological indicators are chosen as variation parameters. The search for the best solution is reduced to the selection of a set of parameters that provide a stationary value of the objective function. Extreme problems of practical orientation contain equality-inequality constraints in mathematical models. In improving the technical characteristics of machines, a significant role belongs to engineering and technical workers, who find optimal options at the design stage. At the same time, an essential element of the design process is the modeling of the determining processes in structures, taking into account the main influencing factors and behavior scenarios. Optimization is an important area of applied mathematics that provides effective tools for such modeling. Universal Algorithm is proposed in work [3] – a numerous scheme for solving quadratic programming (QP) problems for calculating the optimal point of a wide range of applied problems. At the same time, the linear programming (LP) problem is considered as a partial case of the (QP) problem. That is, in the universal algorithm for setting 2 optimization problems, they are formalized in a single and convenient form of symmetric matrix dependence, which makes it possible to build a single effective algorithm based on matrix algebra operations. In particular, it allows you to consider the practical tasks of calculating VAT in constructions of a variable structure consisting of separate parts connected by one-way connections. The main goal of this work is to analyze the behavior of the algorithm when increasing the number of constraints of the inequality type, to refine the computational scheme, and to formulate conclusions. Two model problems are considered as examples of the algorithm. This is a classic \"transport\" problem of LP and the behavior of a model of a bridge structure with one-way connections in cables under variations of wind loads. The number of ropes has been increased to 20, and the limits of one-way connections to 40.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138949069","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 software tool for remote control of knowledge","authors":"Oleksandr Kovtun, Oleksii Linnyk, K. Ivanchenko","doi":"10.20998/2078-9130.2023.2.293691","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.293691","url":null,"abstract":"The purpose of this study was to develop and implement an information system for evaluating and testing students' knowledge in order to simplify the process of creating tests and evaluating the educational achievements of teachers. In the course of the work, a review of existing computer training programs, an analysis of the market of modern analogues was carried out, and on the basis of the obtained data, functional and non-functional requirements for the developed software product were formulated. Based on the requirements, technical and software tools were chosen for the development of the program, namely the JavaScript programming language and the ReactJS framework for the development of the client part of the web application, which allows for quick and convenient development of interactive user interfaces and guarantees the stable operation of the system. The server part of the application is implemented using the powerful and flexible Spring framework, which allows you to create scalable and high-performance web applications. \u0000To achieve the goal, the following tasks are solved in the work: registering a new user, editing user data, logging in and out of the system, viewing/creating/editing/deleting a study group, viewing students of a selected group, viewing/creating/editing/deleting/ publishing a test, viewing/creating/editing an exercise in a separate test, receiving all exercises in a selected test, assigning a test to a selected group, the ability to view/take tests assigned to the user (his group), the ability to check exercises and assign a grade (some exercises may be evaluated by the system automatically if the teacher gave the correct answer for comparison), the ability to view the result for the passed test. A MySQL database was designed and built according to the described data model that corresponds to the third degree of normalization. The structural and functional scheme of the system has been developed. There are three user roles: administrator, teacher, student. Great importance was attached to ensuring the simplicity and ease of use of the user's product, as this plays a key role in the use of the software. In the process of developing the program, great attention was paid to creating an intuitive and comfortable interface. \u0000As a result, an information system for automated testing was created, which successfully fulfills the assigned tasks and meets all the specified requirements, and is also fully ready for practical implementation. The obtained results can be used both to integrate the program into the educational process and to provide students with the opportunity to acquire practical skills","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"46 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138951670","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":"Comparative analysis of the dynamic characteristics of all-metal, composite and composite blades with the same profile, taking into account the influence of the connection of elements and aerodynamic loads","authors":"Volodymyr Martynenko","doi":"10.20998/2078-9130.2023.2.292982","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.292982","url":null,"abstract":"The paper presents a comparative analysis of the dynamic properties of the blades of one rotary machine which have the same airfoil shape, but are made of three different materials, namely aluminum alloy, a complex material combining aluminum alloy and steel, and a composite material which is unidirectional fiberglass. In the case of an all-metal blade, its airfoil and root are made of aluminum alloy. In the case of complex blade airfoil material, the root is made of steel which is also a component of the airfoil material. In the case of a composite blade, the root is steel and is connected at the root section to its composite airfoil. The main attention when comparing models of the mechanical behavior of three types of blades is paid to the influence of the connection of complex and composite elements with the root on the dynamic characteristics of the blade as a whole which is achieved by considering the contact interactions of the elements under the action of centrifugal and aerodynamic loads and the subsequent transfer of the prestressed state of the blades to the modal analysis for determination of the dynamic characteristics of samples and their comparison. In order to correctly display the fixation of elements in the fan impeller in the case of an aluminum blade, the sector of cyclic symmetry of the rotor is considered which makes it possible to draw a conclusion about the possibility of further separate consideration of the blade for determination of its dynamic characteristics due to the much greater stiffness of the connection of the blade with the impeller in comparison with stiffness of the blade airfoil, and to generalize this conclusion in the case of a complex blade by considering a steel root with an aluminum profile with rigid clamping of the model on the contact shelves of the root, and in the case of a composite blade by considering an airfoil with rigid clamping in the root section, where the fastening to the steel root of the blade takes place. The results of a comparative analysis of the dynamic behavior of three types of blades with the same airfoil shape are presented in the form of a study of the blade natural frequencies and mode shapes.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"6 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138952153","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-turn stepped spindle shafts on nonlinear elastic supports","authors":"Valerii Havin, O. Kyrkach, B. Kyrkach","doi":"10.20998/2078-9130.2023.1.293518","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.293518","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":"19 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138952950","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":"Analytical-numerical modeling of the process of solid body orientation in quaternions through a sequence of Euler angles for accurate analysis of orientation algorithms in SINS","authors":"Yu A Plaksiy, Yuriy Kuznyetsov","doi":"10.20998/2078-9130.2023.2.293474","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.293474","url":null,"abstract":"Two concepts for constructing analytical angular test motions of a rigid body for testing orientation algorithms when designing strapdown orientation systems are considered. The first concept is based on representing the orientation quaternion in a sequence of three Euler angles. The second concept is based on a formalized representation of the quaternion as a superposition of trigonometric functions of linear arguments and does not have a clear visual interpretation through the angles of elementary rotations. Analytical expressions for the model angular velocity can be obtained from the inverted kinematic equation in quaternions. The general case of linear Krylov and Euler angles is considered, as well as the case when one of the angles does not change over time. Analytical-numerical modeling of the angular motion of a rigid body and an assessment of the accuracy of the algorithm for determining the quaternion based on fourth- and fifth-order expansions with preliminary application of the Miller algorithm were carried out. For this purpose, the test movement model is supplemented by modeling ideal information from the outputs of angular velocity sensors in the form of quasi-coordinates using analytical formulas for the apparent rotation vector. It is shown that fifth-order formulas provide an improved estimate of the accumulated computational drift compared to fourth-order formulas.  \u0000Keywords: Euler angles, orientation vector, quaternion, reference model, test motion, quasi-coordinates, Miller orientation algorithm, numerical-analytical modeling, accumulated drift.  \u0000 ","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"59 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138949847","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":"Minimization of the weight of the blade of the aerial installation by an adaptive hybrid optimization method","authors":"Konstantin Lapitan, Serhii Misura, Daria Listrova, Tetiana Rudenko, Ievgeniia Misura, Anatolii Vasiliev","doi":"10.20998/2078-9130.2023.1.282064","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.282064","url":null,"abstract":"In various fields of engineering practice, such as turbine building, power engineering, elements of thin-walled structures are widely used, which operate under increased loads when interacting with air or water. These include blades of impellers of radial-axial and rotary-blade hydraulic turbines, blades of wind power plants. Designing highly efficient machines and structures with the required level of reliability requires determining their optimal characteristics. The article proposes an adaptive method for finding the minimum of an arbitrary smooth multivariable function. The method was used to solve the benchmark optimization problem of a function in the form of a valley. The essence of the proposed algorithm lies in the sequential approach to the bottom of the valley and the subsequent movement in the direction of decreasing the objective function. Comparison of the results of calculating the minimum point of the function is performed using both non-gradient and gradient methods, namely: Powell, Hook-Jeeves, the steepest descent method and the developed method. It was found that the effectiveness of the proposed method is greater than the usual search algorithms, but it is not without its drawbacks. The method is proposed that represents a number of hybrid methods, which form a hybrid coalition Proposed hybrid algorithm does not provide a satisfactory result in the \"single\" search. The search algorithm reaches a point where all the values of the function at the surrounding points are greater than the values at the obtained point, and the algorithm cannot overcome the barrier. To solve the problem, it is necessary to take the obtained point as a new starting point and repeat the algorithm for finding the minimum of the function, that is, use the multistart method. The proposed method was used to solve the problem of optimizing the blade of an air installation, which was reduced to the problem of unconditional optimization using the method of penalty functions, but the goal function had a significantly valley structure. The optimal values of section thicknesses were obtained, which made it possible to build a blade with improved characteristics.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"10 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138953100","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":"An improved algorithm for solving inverse problems of the dynamics of robotic devices at SCAS KIDYM","authors":"Yuriy Andrieiev, Vasyl Dziuba","doi":"10.20998/2078-9130.2023.2.293010","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.293010","url":null,"abstract":"The paper presents the results of studies of an analytical algorithm for constructing a resolving system of linear equations to determine the driving forces and moments in the links of robotic devices of arbitrary structure during movement. This algorithm is implemented as an analytical algorithm in a special computer algebra system (SCAS) KiDyM, on the basis of which numerical calculations of the specified forces and moments are generated in the process of performing work processes, positioning mechanisms in the required positions, parking movements, etc. The KiDyM software package is used to solve mechanics problems of a wide class of discrete mechanical systems of arbitrary structure and type of motion for engineering and scientific calculations. A theoretical justification for the developed new approach, analytical and numerical proof of its effectiveness from the point of view of the process of automatically obtaining resolving equations, computational efficiency and accuracy of results are presented. The proposed algorithm is the result of the development of an algorithm that was previously implemented in SCAS KiDyM and was similar in purpose. Unlike the previously implemented algorithm, which generates a resolving system of equations after constructing the dynamic equations, the new algorithm is built into the process of generating dynamic equations - it sorts the model elements - inertial, dissipative, elastic and force elements of known forces and moments form the right side, and force elements with unknown forces and moments, they form a matrix of the left side of equations that solve the inverse problem of dynamics. The article gives a comparative analytical conclusion of one and another algorithm and shows the coincidence of the resulting equations. Also, using examples of calculations of the inverse problem of the dynamics of a portal crane and two 6-degree manipulators, the advantages of the new approach are shown.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"9 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138948613","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 simulation of creep of a cylinder in contact with rods of semi-cylindrical cross-section","authors":"D. Breslavsky, P. Palamarchuk","doi":"10.20998/2078-9130.2023.1.286192","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.286192","url":null,"abstract":"The paper is devoted to the description of the problem statement, the modeling approach, and the obtained results on the creep of a thick tube when it is in contact with rods of semi-cylindrical cross-section, which are located symmetrically to its center. An overview of research papers made in the direction of creep contact modeling, including the FEM use, is presented. The formulation of the problem is presented taking into account finite strains and displacements. The contact conditions are described, the variational functional used for the finite element formulation of the problem is presented. Due to the existing symmetry of the geometric parameters and boundary conditions of the problem, it was solved using the plane strain statement. The area of FEM discretization is the fourth part of the tube cross-section, which is in contact with the cross-section of the rod in the form of a half circle. The results of verification studies performed to assess the reliability of solving the creep problem for the cylinder loaded with internal pressure are presented. Different models are discussed for describing the contact interaction, which can be used in the ANSYS software. The advantages of using the Normal Lagrange Method are shown. The tube contact deformation during creep for 10,000 hours was analyzed. The distributions of the components of the stress-strain state obtained by computer modeling along the sections of the contacting elements and the plot of the redistribution of von Mises equivalent stress at the point of contact are presented. The characteristics obtained by calculations of the deformed state of the surface of the cylindrical tube, which arises due to the influence of the contacting rod, are discussed. An approximation was made and analytical expressions of the dependence of the von Mises stress and the length of the contact line on time were presented. The obtained results of solving the creep problem indicate that within approximately 1.25 years due to the contact of the tube with the rods, dent-type defects are formed on its surface.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"55 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138951933","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 simulation of a rotor creep","authors":"D. Breslavsky, P. Palamarchuk, A. Senko, Oleksiі Marusenko","doi":"10.20998/2078-9130.2023.2.292052","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.2.292052","url":null,"abstract":"The issue of determining the stress-strain state during creep in models of rotors of steam and gas turbines is considered. The formulation of the problem is based on the general approach of Solid Mechanics using incremental theory to describe creep strains. The Finite Element Method was used as a solution method in the implementation of professional engineering software. The influence of the centrifugal forces on the stress-strain state, which varies during 10,000 hours of creep of the rotor material, is analyzed. Two models of the rotor are considered: a simplified cylindrical and a drum-type rotor, which is described by the geometry of the body of revolution and which consists of several cylindrical parts. Due to the symmetry of the models, the calculation schemes are built on the basis of the use of a two-dimensional finite element of the body of revolution. Algorithms are applied for the preparation of input data can be recommended for use in the design practice of energy industry enterprises. The Norton law was used for creep calculations. The creep of the models in different temperature conditions with the use of various steels used in turbo-building as their material was analyzed. According to the results of the performed computer simulation of the creep of rotor models, the levels of deformation and the nature of the redistribution of stresses that occur under the same load by centrifugal forces in different temperature conditions caused by the operational processes in the turbine have been established. The stress and strain levels in the drum-type rotor were analyzed and the most loaded and deformed areas of it were determined. It is noted that according to the simulation data for the considered model of the drum-type rotor, the level of accumulated strains, is moderate and does not exceed 0.4%, which is suitable from the point of view of the analysis of operational properties.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"37 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138948123","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":"Analysis of the state of the problem of improving the armor-piercing properties of personal protective equipment: a review study","authors":"Serhii Dobrotvorskiy, Dmytro Trubin, Y. Basova, Borys Aleksenko, L. Dobrovolska","doi":"10.20998/2078-9130.2023.1.293516","DOIUrl":"https://doi.org/10.20998/2078-9130.2023.1.293516","url":null,"abstract":"The object of the study is personal protective equipment such as body armour, and the subject of the work is the study of the processes of destruction of the integrity of personal protective equipment such as body armour in order to find ways to improve their strength characteristics. Protective body armour is a key element of protection for the military, law enforcement agencies and other professions involving risk to life. Modern materials and technologies make it possible to produce bulletproof vests of the highest level of protection, providing not only protection against bullets but also against other hazards such as explosions and shrapnel. However, the systems must have improved ballistic efficiency, be lightweight, flexible and comfortable for effective work. In general, the effectiveness of protective body armour is determined by various factors, including the construction technique of the vest, the type of materials and the finish of the protective panels. \u0000This paper provides a detailed overview of the current state of the art in body armour panel design and various materials for the manufacture of protective plates. A detailed analysis of the different types of protective body armour and their categories is provided. Next, various methods of panel construction, their problems and possible solutions will be presented. Finally, various polymeric fibre and future possible advanced materials, including carbon nanotubes (CNTs), graphene CNTs and super thickened fluids (STFs), will be discussed for the development of enhanced protection panels.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"54 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138949535","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}