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Criteria of multiaxial fatigue life
Bauer, David ; Slámečka, Karel (referee) ; Horníková, Jana (advisor)
This bachelor's thesis focuses on determination of lifetime of material under multiaxial cycle loading. This knowledge is important for a good design of the most machine parts. The thesis includes a short description of the proces of material fatigue, which is consequence of cyclic loading. It contains fatigue criteria for the case of uniaxial and multiaxial loading too. From a large number of multiaxial criteria are chosen energy-based and stress-based models.
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Prediction of furnace tubes corrosion using operating data
Kolomazník, Milan ; Kilkovský, Bohuslav (referee) ; Jegla, Zdeněk (advisor)
The thesis deals with the modeling and prediction of corrosion of radiation tube snake in the heating furnace. Specifically it is focused on vertical cylindrical furnace which is included in the catalytic hydrocracking unit and serves for heating aggressive circulation gas which is the cause of high temperature corrosion. An important basis for the creation of computational models are available records about the operation of the furnace and about the corrosion and degradation mechanisms during the lifetime of the tube system in furnace. Such information enables the creation of a computational model which is based on the prediction of high-temperature corrosive damage of radiation tube snake. The computational model involving all relevant factors may serve as the basis for a predictive life management system of radiation snakes in the heating furnace.
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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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Fatigue life prediction models
Hurta, Filip ; Vaněk, František (referee) ; Sladký, Martin (advisor)
Evaluation of fatigue is essential for determining operational capabilities of mechanical parts. Principles of material fatigue are discussed in this bachelor thesis. Most attention is paid to linear elastic fracture mechanics and variable amplitude loading. There are mathematical models, that describe conditions in the center of damaging. In the text there are described chosen models based on fracture mechanics. On basis of the conducted research, a computer program was developed, solving a crack growth in a specimen, depending on the defined loading. This program does not consider interaction effects during the loading sequence. Program output validation was performed by comparison of given results with the calculation and tests results from the literature. The data correlate with the non-interaction predictions, but comparison with the reality demonstrates the importance of interaction effects in complex loading.
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Defect acceptability according to procedures R6, BS 7910, ASME Xi, and NTD ASI, for given sets of assumptions, input data, and defect characterization.
Joch, Jaroslav
The report compares the approaches of four procedures (R6, B6 7910, ASME XI, and NTD ASI) for the evaluation of defects identified during the NPP shutdown NDT inspections. The focus is on defect characterization, ie. the ideal crack for the evaluation, and on comparing various approaches with the data available and the level of conservatism required. Both similarities and differences in the procedures are highlighted, as well as the historic and philosophical background of the procedures.
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Prediction of furnace tubes corrosion using operating data
Kolomazník, Milan ; Kilkovský, Bohuslav (referee) ; Jegla, Zdeněk (advisor)
The thesis deals with the modeling and prediction of corrosion of radiation tube snake in the heating furnace. Specifically it is focused on vertical cylindrical furnace which is included in the catalytic hydrocracking unit and serves for heating aggressive circulation gas which is the cause of high temperature corrosion. An important basis for the creation of computational models are available records about the operation of the furnace and about the corrosion and degradation mechanisms during the lifetime of the tube system in furnace. Such information enables the creation of a computational model which is based on the prediction of high-temperature corrosive damage of radiation tube snake. The computational model involving all relevant factors may serve as the basis for a predictive life management system of radiation snakes in the heating furnace.
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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.
|
|
|
Criteria of multiaxial fatigue life
Bauer, David ; Slámečka, Karel (referee) ; Horníková, Jana (advisor)
This bachelor's thesis focuses on determination of lifetime of material under multiaxial cycle loading. This knowledge is important for a good design of the most machine parts. The thesis includes a short description of the proces of material fatigue, which is consequence of cyclic loading. It contains fatigue criteria for the case of uniaxial and multiaxial loading too. From a large number of multiaxial criteria are chosen energy-based and stress-based models.
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