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Design of the composite rotor sleeve of a high speed rotary machine
Pavlík, Ondřej ; Ševeček, Oldřich (referee) ; Návrat, Tomáš (advisor)
The diploma thesis focuses on manufacturing carbon fiber and epoxy composite material using filament winding method. Material properties of manufactured composite are ap-proximated using analytical and numerical homogenization models. Calculated material properties are applied to design and evaluate reserve factor of retaining sleeve for high speed brushless permanent magnet synchronous motor. Margin of safety of designed rotor is evaluated using composite failure criteria. Test stand for both static and dynamic testing is designed, static test stand is manufactured and assembled. Static strength test is carried out.
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Mechanical design of impact simulator under reduced gravity
Melichar, Marek ; Pokorný, Jan (referee) ; Návrat, Tomáš (advisor)
The diploma thesis is focused on the development of the concept of a mechanical device that would meet the necessary requirements to achieve a successful simulation of reduced gravity or microgravity on the tested body at its impact. The choice of a suitable mechanism is based on a literary research of all available variants and highlight of their specifics. Target values are created for the selected method of testing, upon reaching which the concept will be considered successful. In order to verify the functionality of the concept, a mechanism is assembled on a smaller scale. The individual components of the mechanism are tested and carefully selected. All essential physical processes taking place in the system are mathematically described and combined into a MATLAB script. A separate application is created to calculate the behavior of the system based on the specified input parameters.
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Stress-strain analysis of the thin wall structure subjected to impact load
Tatalák, Adam ; Peč, Michal (referee) ; Návrat, Tomáš (advisor)
This master thesis deals with stress-strain analysis of simplified model of the thin wall transformer case subjected to impact load of electrical blast. Electrical blast is replaced by chemical blast (detonation of high explosive). The problem is solved using computational modeling utilizing the Finite Element Method (FEM) and LS-DYNA solver. After the introduction where detonation and shock wave propagation is explained the analytical approach is presented. This approach serves to results verification. In the next chapter is conducted research of applicable methods from which ALE method is chosen. In preliminary study is performed the mesh size analysis that is focused on finding the size of element which is both computational effective and gives accurate results. Next the infulence of input conditions (shape, location and parametres of high explosive, location of detonation point, boundary conditions) on distribution and time progress of pressure is investigated. Then influence of the opening on upper side of the case on overall pressure redistribution and strain and stress of the case is analysed. The stress-strain analysis of the case´s door which are connected to case by various types of contact models is performed as well as stiffness analysis of these types of contact.
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Calculation of natural frequencies of a bar system using finite element method
Svoboda, Petr ; Kubík, Petr (referee) ; Návrat, Tomáš (advisor)
The task of the presented bachelor thesis has been to program an algorithm of the finite element method to calculate natural frequencies of beam systems. To solve this problem a freely available SW products (Python, libraries NumPy, SciPy, Fortran compiler etc.) should have been primarily used and thereby to check possibilities of freely available SW product application in science purposes in the field of the Continuum Mechanics tasks. For a functionality verification of the program the ANSYS code is to be used.
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Design adjustment of vacuum ejector assembly for medical application
Boháč, Petr ; Štefan, David (referee) ; Návrat, Tomáš (advisor)
This bachelor's thesis deals with the design of a two-stage suction ejector for medical use with the working name Medieject II. The proposed modifications are to achieve a reduction in the value of the created vacuum compared to the original value, and thus also enable a more precise regulation of the created vacuum. The first part of the thesis presents the theoretical assumptions, functions and requirements for a multistage suction ejector, which is to serve in a medical environment. The second part describes the analytical calculation of the original variant, which serves as a partial check of subsequent numerical simulations. The third part deals with CFD simulations, which are used as the main solving method for adjustments. Using flow simulations two design modifications and their several partial variants are proposed. Then these modifications are supported by experiment. The second design proposal will be used to manufacture equipment that will fulfill the requirements.
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Stress-strain analysis of artery with atheroma
Janík, Rostislav ; Návrat, Tomáš (referee) ; Burša, Jiří (advisor)
This master thesis analyses stress and strain of iliac artery with atheroma. Model of artery is created as 2D and symmetric about the y-axis. The first part of the thesis deals with a research, which includes obtaining information from medicine, which is necessary fort the right solution of the task. Next part dedicates to nonlinear mechanics, constitutive modeling from the view of biomechanice and computational modeling of arteries. In the next part is made analysis for load on artery by physiological and also by high blood pressure. In the end were specified uncertainties of the used model and evaluated chance of atherosclerotic plaque rupture.
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