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Strain, stress and strength analysis of the frame construction.
Kysilko, Vít ; Damborský, Petr (referee) ; Vrbka, Jan (advisor)
The bachelor´s thesis is intent on the computation of a plane frame which is used for test the resistance of composite tubes to a changing pressure. As a computational model I used simplified frame loaded by solitary forces which work eccentrically from the axis of symmetry of the frame. Because I cannot exactly use the theory of simple elasticity and strength in this task I make two calculations with various shapes of midline. This is twice internally statically indeterminate task, appropriate deformation conditions were solved by Castigliano’s theorem. Bending stress is dominant but in calculation is also composed energy of normal and displacement forces. Inspection of cyclic fatigue was made in possible hazardous places. Analytic calculation was carried out in MAPLE 12 and it was compared with Finite Element Method analysis with Ansys Workbech 12 software.
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Fatigue analysis and life of steel structures
Dostál, Petr ; Šťastný, Antonín (referee) ; Kubín, Martin (advisor)
The thesis is focused on solutions fatigue´s analysis and consequently on persistence steel structures of engineering and building aspects. The theoretical part describes the influence of cyclic fatigue in steel structures, describe the basic characteristics of fatigue and its application, a description of the fatigue life curves and their subsequent mathematical approximation of both engineering and the building terms. The study also includes the calculation of fatigue real parts (structure) in mechanical engineering, depending on the operating conditions of the structure. The work is further prediction of the life of steel structures using damage accumulation hypothesis according to the nominal stress. The practical part composes an example of life calculation of drawbar tractor-trailer bogie suspension of engineering and building terms. An example serves as an algorithm solving the life prediction of engineering and building terms, and reveals the possibility of solving the life of engineering structures in terms of building. The comparison of both approaches is done in conclusion.
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Evaluation of the properties of NiTi instruments in current endodontics
Bumbálek, Michal ; Klíma, Karel (advisor) ; Németh, Tibor (referee) ; Barényi, Igor (referee)
Introduction: One of the key prerequisites of high-quality endodontic treatment is the use of endodontic NiTi instruments for the preparation of root canals. The purpose of this dissertation is to evaluate the effect of individual factors which influence the life of endodontic instruments during the clinical treatment of root canals. The dissertation will evaluate the effect the curvature of the canals, the shape of the tip of the instrument, the speed and type of rotation, and the influence of sterilization. The effect of low-temperature plasma nitriding on the fatigue life of the instruments will also be investigated. Materials and methods: Several endodontic systems used for the machine preparation of root canals were studied. The study focused predominantly on the cyclic fatigue of rotary endodontic instruments, wherein the files were rotated in artificial curved root canals. Additionally, the influence of sterilization on the life of the instruments was also examined. Finally, the instruments were treated using thermal plasma nitridation for the purpose of improving their properties. The instruments were then analyzed using a scanning electron microscope and a microhardness meter. Results: Testing cyclic fatigue in artificial root canals with radii R3 and R5 revealed that instruments with a...
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Fatigue analysis and life of steel structures
Dostál, Petr ; Šťastný, Antonín (referee) ; Kubín, Martin (advisor)
The thesis is focused on solutions fatigue´s analysis and consequently on persistence steel structures of engineering and building aspects. The theoretical part describes the influence of cyclic fatigue in steel structures, describe the basic characteristics of fatigue and its application, a description of the fatigue life curves and their subsequent mathematical approximation of both engineering and the building terms. The study also includes the calculation of fatigue real parts (structure) in mechanical engineering, depending on the operating conditions of the structure. The work is further prediction of the life of steel structures using damage accumulation hypothesis according to the nominal stress. The practical part composes an example of life calculation of drawbar tractor-trailer bogie suspension of engineering and building terms. An example serves as an algorithm solving the life prediction of engineering and building terms, and reveals the possibility of solving the life of engineering structures in terms of building. The comparison of both approaches is done in conclusion.
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Strain, stress and strength analysis of the frame construction.
Kysilko, Vít ; Damborský, Petr (referee) ; Vrbka, Jan (advisor)
The bachelor´s thesis is intent on the computation of a plane frame which is used for test the resistance of composite tubes to a changing pressure. As a computational model I used simplified frame loaded by solitary forces which work eccentrically from the axis of symmetry of the frame. Because I cannot exactly use the theory of simple elasticity and strength in this task I make two calculations with various shapes of midline. This is twice internally statically indeterminate task, appropriate deformation conditions were solved by Castigliano’s theorem. Bending stress is dominant but in calculation is also composed energy of normal and displacement forces. Inspection of cyclic fatigue was made in possible hazardous places. Analytic calculation was carried out in MAPLE 12 and it was compared with Finite Element Method analysis with Ansys Workbech 12 software.
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