Interference fit joints have been widely used in many engineering constructions, in particular in electric motors. It is of particular importance to calculate the load capacity of press-fit joints, especially in the overload ranges of construction to estimate the safety factor. The article presents a FEM numerical simulation of pressing the shaft into the hub, taking into account various types of fits. The results of numerical simulations presented in the article were positively verified with the MTS measuring device, which confirmed the correctness of the numerical model. So far, the load-bearing capacity of press-fit joints has been calculated from Lame’s formulas. The results of the load capacity of the joints obtained by the FEM simulation were compared with the results obtained from Lame’s formula. The comparison shows that when designing interference fit joints, attention should be paid to the fact that the press-in process, depending on the type of fit, may be elastic-plastic. Plastic deformations in the contact zone of the joint affect its load-bearing capacity. Therefore, the design of press-fit joints should not be based on Lame’s formulas, which do not take into account the range of plastic work of the material.
In the article the analysis of airflow through electrical motor was conducted and optimal design solution was chosen in order to increase cooling efficiency. Numerical simulations allow to determine the areas of temperature occurrence which may have destructive influence on electrical motor parts and on its safe operation. The numerical calculations of airflow was carried out for two different types of fans as well as for two different housings. An analysis of the construction was carried out by CFD method using Autodesk Simulation CFD 2013. Community results of the analysis, we can conclude that the better solution for machines with fixed direction of rotation is to use instead of the radial the axial fan. For axial fan the motor temperature in the same condition was lower by about 5°C.
The innovaTive design concepT of Thermal model for The calculaTion of The elecTromagneTic circuiT of roTaTing elecTrical machines innowacyjna koncepcja budowy obliczeniowego modelu cieplnego dla obwodu elekTromagneTycznego wirujących maszyn elekTrycznych* Operating parameters and reliability of rotating electrical machines are connected to a large extent with their thermal state. The high temperature of these devices has an impact on the life of such elements as bearings, windings, andalso efficiency and possibility of their use. More often, during the analysis of the existingand new designs of electrical machines,the thermal and mechanical calculations are carried out. The finite element method which uses spatial models is commonly used in such calculations. The correct formulation of boundary conditionsand the appropriate model simplifications are the key problems. Parameters calibration of thecalculation model in order to obtain adequate calculations results to the actual device operation is necessary to performed. The innovative conception for determining the thermal parameters of the numerical model for the most complex structure of electrical machinery, which is the electromagnetic circuit, is presented in this paper. During the preparation of the thermal IntroductionGrowing demands on the efficiency of electric motors, as well as economic aspects and diversity of application cause that in the design of electrical machines not only electrical parameters are important.The higher reliability, minimize weight and dimensions, high strength, and appropriate vibration, noise and thermal stateparameters are required from actually designed and manufactured electrical machines [1,[4][5][6]10]. In other words, electrical machines should be optimized to working conditions in which they are operated. This approach necessitate development of newer and more elaborate design. At the same time in the design process of modern electrical machines the interdisciplinary knowledge in the field of electrical engineering, electronics, strength sciENcE aNd tEchNology of materials, thermodynamics, fluid mechanics and acoustics is required from constructor.The development of computer technology and constantly increasing computing capabilities have contributed to the development of numerical methods and increasing popularity of programs supporting the work of design engineers. Skillful use of specialized software in the design of electrical machines can increase the efficiency of project work and motor durability simultaneously reducing their weight, vibration, noise and temperature. In the available publications, it can be seen that more often to thedesign analysis of electrical machine researchers use sophisticated computational programs. In addition to the mechanical analysis, software for thermal and flowanalysis based on FEM and CFD or the Lumped Parameter Modelingis becoming more popular [2].In the literature related to this subject, different ways of modeling and calibration of computational models and related problemscan be...
A hot spot at the outer rim of the accretion disk dominates the light of U Geminorum at minimum light. We take this as evidence that there is no accretion from the disk onto the white dwarf between the eruptions, and we assume there is no viscosity in the disk at that time. The hot spot is produced by dissipation of the radial component of velocity of stream falling from the inner Lagrangian point. Angular momentum per unit massis smaller in the stream than it is in the outer parts of the disk. This leads to angular momentum redistribution in the outer part of the disk. The difference of tangential velocity between the stream and the disk is dissipated in few orbital periods. These processes make the outer parts of the disk look like a torus. We calculated the structure of the torus in U Geminorum between the eruptions and we obtained the following oarameters: mass of the torus: 10-9 - 10-8 M⊙ (assumed), its optical thickness: 106, the large radius (i.e. the radius of the disk): 0.5 R⊙ (assumed), the small radius (i.e. the half thickness of the outer parts of the disk): 0.05 R⊙. Conditions at the surface of the torus are similar as on the solar surface.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.