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Determination of Material Properties of Silicone Used for Experimental Modeling of the Human Vocal Folds
Podkalský, Stanislav ; Hrubanová, Anna (referee) ; Hájek, Petr (advisor)
The presented bachelor thesis focuses on a comprehensive analysis of the material properties of silicone models used in experimental vocal fold models. This thesis includes analysis of the literature in which the authors have addressed this issue and appropriately follows up with an own experiment in the form of a tensile test resulting in constitutive models for the accurate determination of the Young's modulus for arbitrary elongation. Models such as the Neo-Hooke model will be used for the hyperelastic nature of the material. At the same time, this work focuses on the statistical treatment of phenomena acting on the silicone material such as material thinning and aging.
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Marginal conditions and their influence in the production of reinforced steel fibres in concrete
Loyková, Markéta ; Řiháček, Jan (referee) ; Císařová, Michaela (advisor)
Constantly increasing demands of customers for the speed of realization of the construction and reduction of all input costs have been reflected in civil engineering by high demand for reinforced steel fibers in concrete. The steel reinforcement has significant role in this composite material. This means that reinforcement (wires) provide the required physicochemical properties to the concrete. It is necessary to pay attention also to the marginal conditions and their influences in the production of wire. In close cooperation with the companies Krampe Harex CZ and Cemex Czech Republic, an analysis of the conditions of the drawing process and subsequent influence of dispersed steel reinforcement on the final product was created. The economic aspects of the production of dispersed steel reinforcement in concrete were also mentioned.
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Seismic test of the switching devices on the low voltage
Dubský, Martin ; Mikyska, Kamil (referee) ; Dostál, Lukáš (advisor)
This work analyzes the seismic tests to valid technical starnards. Here is explained the term technical standard and written summary requirements for seismic resistance circuit breakers low voltage. The work includes devices suitable for the purpose and extreme laboratories dealing with seismic tests. The final section provides a draft test station with estimated economic return. Seismic tests are a very important part in the design of not only switching technology. It allows you to simulate the selected mechanical effects which may on the unit during operation or transportation to work and increase its reliability.
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Welding of the framework from aluminium alloys
Rašek, Ondřej ; Daněk, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
For TIG welding of transformer fame is important enough weld root fusion, however exposed surfaces must remain unaffected. Three types of test were made to determine properties of welds under different conditions. Tests were macroscopic inspection, tensile test and fracture test. Next was economic evaluation of different methods. Best results were for single layer weld with pre-heated material.
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Technological tests of pipes
Horák, Michal ; Staněk, Vojtěch (referee) ; Peterková, Eva (advisor)
The submitted project created in the bachelor studies of B-STI Machinery engineering is focus on problematic of technological tests of pipes. Based on the research of literature and internet mentioned problematic the bachelor thesis describes principle of individual technological tests, the procedure for the evaluation and application. For a complete picture of test tubes in the thesis are also given basic information about the mechanical tests.
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Influence of lamine thickness on bifurcation appearance in ceramic laminate
Sorokina, Kristina ; Ševeček, Oldřich (referee) ; Hadraba, Hynek (advisor)
Z důvodu rozdílných koeficientů délkové teplotní roztažnosti jednotlivých vrstev vzniká ve vrstvách keramického vrstevnatého kompozitního materiálů reziduální napětí. V průběhu chladnutí vrstevnatého kompozitu ze slinovací teploty jednotlivé vrstvy smršťují různými rychlostmi v závislosti na velikosti koeficientu délkové teplotní roztažnosti. Jestliže jsou tyto vrstvy spolu pevně spojeny vzniká v jednotlivých vrstvách různě velké trvalé zbytkové napětí. Velikost residuálního napětí je dána objemovým podílem obou složek v kompozitu. Tato práce byla zaměřena na přípravu a popis 7-mi a 9-ti vrstevných keramických laminátů složených ze střídajících se vrstev dvou rozdílných materiálů. Keramické lamináty byly připraveny pomocí metody suspenzního lití a elektroforetické depozice. U připravených laminátu byl sledován vznik tzv. hranových trhlin (edge cracks) ve vrstvách obsahujících tlaková zbytková pnutí. Výsledky pozorování přítomnosti hranových trhlin pro různou konfiguraci velikosti zbytkových napětí a tloušťky vrstev byly srovnány s teoretickou předpovědí vytvořenou pomocí parametrického 2D modelu. Vliv vzniklých hranových trhlin na průběh lomu byl studován pomocí 3D rekonstrukce lomového povrchu po ohybové zkoušce připravených vrstevnatých kompozitů.
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Analýza tahové-tlakové asymetrie u koeficientů příčné deformace pomocí metody korelace digitálního obrazu
Zadina, Jan
This thesis deals with the analysis of tensile-compressive asymmetry in the coefficients of transverse deformation (Poisson's ratios) of spruce wood (Picea abies L. Karst) in all three principal directions of growth, i.e. for the complete set of 6 Poisson's ratios. Tensile and compressive stress within one direction was applied to the same test specimen, and the digital image correlation (DIC) method was used to analyze surface deformations. For this purpose, the surface of the test specimens in two adjacent planes was recorded by cameras during mechanical loading, and the deformations were fully evaluated from the digital images, from which the Poisson's ratios were subsequently calculated. The evaluation of Poisson's ratios was performed using statistical tests. Statistical t-tests were performed to test the equality of means to compare the tensile and compressive Poisson's ratios, which showed differences between the compressive and tensile Poisson's ratios only in some cases. A one-way ANOVA and Scheffé's test were also performed to compare the different directions with each other, which showed a distribution of large and small Poisson's ratios mainly in tension. A regression analysis was also performed to determine the degree of correlation between the tensile and compressive Poisson's ratios, and correlation was demonstrated in the radial and tangential directions. Regression analysis was also performed to examine the relationship with wood density, which showed a slight correlation with some of the Poisson's ratios.
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Destruktivní metody testování materiálu
Veverka, Vilém
The submitted bachelor's thesis deals with destructive methods of material testing with a focus on tensile testing and material fatigue. The aim of the bachelor's thesis was to prepare an overview of individual destructive methods of material testing and comparison of tensile diagrams of samples. In the bachelor's thesis, 3 types of samples were investigated, which were printed on a Prusa i3 MK3s 3D printer from ABS, PLA and PETG materials. Test specimens were modeled in Fusion 360 according to ASTM D638. The tensile test was performed on a ZDM 5/51 universal tensile machine according to the ASTM D638 standard. The results show that the sample made of PLA material has the highest tensile strength of 41,23 MPa.
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Design proposal and modal analysis of fixture for CubeSat vibration tests
Pospíšil, Jakub ; Bartoněk, Jaroslav (referee) ; Lazar, Václav (advisor)
Hnutí CubeSatů se v současné době těší vzrůstající oblibě, především díky možnosti zapojení širšího okruhu institucí do vesmírného výzkumu. Tento zájem zároveň vyvolává nutnost provádět mechanické zkoušky CubeSatů dříve, než je bude možné vypustit do vesmíru. Tato závěrečná práce zpracovává problematiku mechanických zkoušek u CubeSatů a provádění jejich vibračních zkoušek. Na základě této rešerše je proveden návrh přípravku o velikosti 6U včetně modální analýzy a ověření vyrobitelnosti.
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