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Modal analysis of vocal folds models with descrete parameters
Lekeš, Filip ; Švancara, Pavel (referee) ; Hájek, Petr (advisor)
Bachelor’s thesis deals with modal analysis of computed models of human vocal folds. It’s about finite element and analytical model where values first eigenfrequencies come under male vocal folds. Research part applies to biomechanics of vocal the human voice, which is followed by an overview of computational models. Finite element model is completely created and solved by ANSYS Workbench commercial program, which uses the finite element method to simulate a problem. Solution of analytical model uses freely available Python programming language. Analysis of the results and comparison of approaches belong to main objectives of the presented work. The proposed analytical model can serve future students for detailed understanding of human vocal oscillations.
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Simulation modelling of blower system
Gajdík, Michal ; Švancara, Pavel (referee) ; Hadaš, Zdeněk (advisor)
This diploma thesis is focused on simulation modeling of Roots blowers, which are produced by Kubicek VHS company. First part of this thesis is about oscillations and its damping. In following phase are analyzed each methods realization and control of oscillation damping. Second part of this thesis is focused on Roots blower modelling with rigid and flexible parts and its verification. Output of this thesis is dynamic analysis of Roots blower 3D28C. On attached CD are program annex and project in Adams MSC. Aim of this thesis is proposing adjustments, which would reduce noise and vibration of analyzed machine.
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Influence of exostoses on hearing
Vališová, Šárka ; Švancara, Pavel (referee) ; Pellant, Karel (advisor)
Exostoses are periosteophyte inside the external auditory canal of the human ear. The main objective of this bachelor´s thesis is to determine the potencial impact of the shape modification of the external auditory canal due to occurence of exostoses on the mechanical sound transmission into the internal ear. The task was solved by FEM modelling performed in the ANSYS system. The simple finite element 2D model of the normal human ear has been taken from the diploma thesis B. Ouali: Development of 2D finite element model of human ear (BUT Brno, 2009), the model included the external ear canal, elastic eardrum, otitis cavity with the otitis ossicles and the cavity of the internal ear. The changes simulating exostoses in form of two opposite semicircles were performed. The different size and position of the symmetrical exostoses were studied. The influence of the exostoses on the sound transfer characteristics of the external ear canal was discused. It was processed the set of the audiograms (19 patients). The results of the modelling and the results of the audiology were compared, the preoperativ and the postoperativ stages were considered.
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Noise and vibrations of roots blowers
Smrček, Martin ; Hájek, Petr (referee) ; Švancara, Pavel (advisor)
This thesis is concerned with the spread of noise in the housing sets blowers, blower vibration, due to the shape of the geometry of the individual parts of the blower and the design of a suitable discharge muffler in order to achieve the highest possible attenuation. Analysis blower and silencer discharge was conducted using the finite element simulation ANSYS 15.0
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Computational modeling of the interaction of flowing blood with the artery tube with the atheroma
Freiwald, Michal ; Jagoš, Jiří (referee) ; Švancara, Pavel (advisor)
Předložená diplomová práce se zabývá interakcí mezi proudící krví a krční tepnou, obsahující aterosklerotický plat, za pomoci konečnoprvkové fluid-structure interaction analýzy. První část práce obsahuje souhrn teoretických poznatků, sestávající z kardiovaskulárního systému, cév, souvisejících konstitutivních modelů, reologie krve a úvodu do teorie proudění. Dále je v práci obsažen stručný souhrn současného poznání výpočtového modelování v této oblasti, s důrazem na strukturní a fluid-structure interaction analýzy v oblasti krční tepny, a na použité konstitutivní modely. Experimentální část se soustředí na tvorbu zjednodušeného modelu krční tepny, obsahující aterosklerotický plat, a na tvorbu odpovídajícího modelu krve. Oba modely poté společně vstupují do fluid-structure interaction analýzy, která si klade za cíl pochopit důsledky pulzujícího toku krve na stěnu tepny a na růst aterosklerotického plátu; primárními zkoumanými veličinami jsou první hlavní napětí na stěně tepny, celková deformace stěny tepny, časově zprůměrovaná hodnota smykového napětí na stěně tepny a oscilační smykový index. Všechny výsledky jsou porovnány napříč několika typy analýz, tak aby bylo možné zhodnotit rozdíly a důsledky zvoleného přístupu. Součástí práce je také zjednodušená parametrická studie, která porovnává vliv rostoucího procenta stenózy na vyhodnocované veličiny. V poslední částí práce jsou zhodnoceny výsledky, její limitace a další možnosti výzkumu v této oblasti.
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Computational modelling of aerodynamic noise caused by the car’s side mirror
Vobejda, Radek ; Hájek, Petr (referee) ; Švancara, Pavel (advisor)
The master’sthesis deals with numerical modelling of aerodynamic noisewhich arisesinside of the carcabin. In the first part ofthe thesis simplified model of geometry of the car and of the inside acoustic pressure arecreated. After that numerical analysis of created models of geometry are doneandvarious models of turbulenceare discussed. The results of these CFD simulationswhere then used for changing the model of geometry of the wing mirror. Outputs of these simulations were used for solving the numerical analysis of noise in the car cabin.
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Computational modelling of function of the human vocal tract
Ryšavý, Antonín ; Hájek, Petr (referee) ; Švancara, Pavel (advisor)
In the first part of this bachelor's thesis is a brief summary of the biomechanics of the creation of the human voice and an overview of the published computational models of the vocal tract and the area around the head. The second part deals with the computational models of the human vocal tract set to the pronouncing the Czech vowels /a:/ and /i:/ with using the method of transfer matrices and the finite element method. By these methods is perform modal and harmonic analysis. Are investigated the natural frequencies and own vibration shapes of both vowels and course of sound pressure in a specific areas of the vocal tract. The method of transfer matrices is highly depend on the geometry of the tract, particularly on the density of the reference sections and its results in this thesis do not completely agree with the results in the literature. Finite element method is more accurate and its results agree well with results reported in the literature, but the opposite of the transfer matrices method is significantly time consuming. Method of the transfer matrices is more suitable for a large number of calculations or tuning certain parameters. Models created in this bachelor's thesis can serve for the analyse of pathology of voice production, eventually for prediction of surgical procedures in the area of the vocal tract.
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Using finite element method for modelling of movement and stress of vocal folds during setting to phonation position
Šíbl, Michal ; Šidlof,, Petr (referee) ; Švancara, Pavel (advisor)
This Master´s thesis deals with use of finite element method for modeling motion and stress of vocal folds during setting to phonation position. The thesis contains a description of the relevant anatomical structures and of the closely related formation of the human voice. A list of some previously published models of the function of human vocal folds follows. A part of my work was to create a model of geometry of the larynx using CATIA V5 and PTC Creo 2.0 on the basis of data acquired by MRI (magnetic resonance imaging). After that the model was converted into the calculation system Ansys Workbench 15.0 and, for solving contact problems, into Ansys Classic 15.0. To solve given problems, these programs use the finite element method (FEM). Solution was carried out for six different variants simulating individual motions of cartilages, corresponding to the activation of individual muscles. For each variant, the movements and stresses in the soft tissue of the vocal folds were evaluated. For variants with activation of IA, TA and LCA muscle it was also evaluated the contact pressure between the vocal folds. Finally, the thesis mentions the preparation of the model for the activation of the vocal folds movement by the muscles of the larynx.
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Influence of Glottal Shape of Human Vocal Fold on its Modal Characteristics
Zelinka, Martin ; Švancara, Pavel (referee) ; Hájek, Petr (advisor)
The main goal of the bachelor thesis is to create a parametric model with a variable angle of the human vocal fold and to determine the first two frequencies of vocal fold oscillations for all angles from -40 ° to + 40 °. The result is supported by a review of the anatomy of the human vocal system, the creation and modification of the voice, and current models of the human vocal fold. The model used for this work is created in the 3D CAD Inventor model software. Modal analysis is solved in the computer program ANSYS Workbench, solved using finite element methods.
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