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Static strength assessment of the weld
Gális, Róbert ; Řehák, Kamil (referee) ; Dlugoš, Jozef (advisor)
This thesis aims to review, summarize and compare the available approaches and standards assessing static strength of welds. In the introductory section, the theoretical knowledge required to assess static strength of welded structures is summarised. In the next section, the algorithms for evaluating static strength of welds using each guideline are reviewed and described in detail. They are also applied to designed T-shaped welded geometry with a two- sided fillet weld. Subsequently, the obtained results are compared and evaluated. Finally, an experiment is drafted to verify the calculations or to determine the most appropriate approach.
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Stress-strain analysis of the process of continuous steel casting
Cabaj, Gabriel ; Petruška, Jindřich (referee) ; Návrat, Tomáš (advisor)
The thesis is focused on the development of a computational model for determination of stress and strain of a round billet in the process of continuous steel casting. The supplied material characteristics, the geometry of the continuous casting machine and the temperature distribution in the billet are applied as input data for stress and strain analysis. The computational model based on the finite element method is developed in the commercial software ANSYS. The thesis can be divided into three parts. The first part includes background information related to the continuous casting of steel and a research analysis of the computational modeling of this process. The second part describes the development of the planar and three-dimensional computational model in detail. Finally, the obtained stress and strain results are analyzed and general conclusions, and recommendations for further development are proposed.
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Analysis of the influence of the fixation setting of the fusion of the spinal vertebrae on the resulting correction of scoliosis
Kopecký, Tomáš ; Ščerba, Bořek (referee) ; Vosynek, Petr (advisor)
This bachelor's thesis deals with the numerical modeling of the spine with an established fixation device under three types of loading, with three types of connection between the last element of the fixator and its guiding rod. The thesis describes the creation of the spine and fixator models, as well as the setting of loading conditions. Three loading states are monitored, in both directions: flexion/extension, lateral bending in both directions, and axial rotation in both directions. Furthermore, the implementation of three types of connections for all these loadings is described. In the first case, the entire fixator is immovable, in the second case, the last element of the fixator can move along the axis of the spine, and in the last case, it can also rotate in all three directions. The evaluation and subsequent comparison of deformation in the direction of the spine axis are the outputs of this thesis. The final evaluation is that the displacement occurring is on the order of tenths of millimeters.
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Using optimization methods to design machine parts
Kubrický, Daniel ; Pokorný, Přemysl (referee) ; Zeizinger, Lukáš (advisor)
This bachelor thesis describes using structural optimization methods to design machine parts. In the first part of the thesis, a description of the current state of knowledge of the optimization process was made together with its theoretical background. In the second part of the thesis, a static analysis and topology optimization or Generative design was developed using the example of a bell crank in six commercial software. In the third part, the resulting models of each software were compared with each other, and the results were compared using the von Mises maximum stress criterion and the overall model deformation. Finally, this work was concluded with an evaluation of the use of the structural optimization software.
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Design and assessment of the load-bearing part of the reinforced concrete structure
Tihelka, Marek ; Lagiň, Juraj (referee) ; Kostiha, Vojtěch (advisor)
The aim of the bachelor thesis is the design and assessment of a reinforced concrete foundation structure of a sports hall. The proposed solution is a monolithic foundation slab. The design software SCIA Engineer 22.0 was used to determine the reactions acting on the slab and slab internal forces. The reactions were also verified by manual calculations. The slab was assessed for ultimate and serviceability limit state and designed by hand. This work also includes design of reinforced concrete monolithic column. A drawing documentation was also prepared for both reinforced concrete slab and column.
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Selected structures of the family house
Kulík, Karel ; Švaříčková, Ivana (referee) ; Perla, Jan (advisor)
The bachelor thesis is focused on the design of selected reinforced concrete structures of the family house, it is a continuous ceiling plate and a staircase. The structures were designed and assessed to the ultimate limit state and the serviceability limit state. Calculations were made using the Dlubal RFEM 6 and Microsoft Excel programs. The outcome of the calculations is a static calculation. The design documentation including form and reinforcment mechanical draws was created in Archicad 26 and CADCON+ RC 2023.
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Modeling electroacoustic systems in COMSOL
Hanuš, Jan ; Honzík,, Petr (referee) ; Schimmel, Jiří (advisor)
The thesis aims to explore the simulation software COMSOL Multiphysics with relevance to the field of electroacoustics. The work covers general introduction to the software, including an outline of the principles of finite element method, which is the most widely used numerical method in COMSOL Multiphysics. It also includes a clear description of the individual steps required to create a simulation. Furthermore, the Acoustics Module is described, Pressure Acoustics physics interface in particular as it is used later on in the simulations. The AC/DC Module and its physical interface Electric Circuit is mentioned briefly as well. Finally, the simulations created by the author are explained in a step-by-step manner. These look at the impact of the membrane’s and waveguide’s geometries on the radiation of the speaker driver, and the shapes of the loudspeaker system’s enclosure with the edge diffraction phenomena in mind. The results of the individual simulations are presented using graphs and discussed afterwards.
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Computational study of the impact of disorders in excitation propagation on left ventricular contraction
Vaverka, Jiří ; Rohan,, Eduard (referee) ; Horný, Lukáš (referee) ; Burša, Jiří (advisor)
Tato disertační práce se zabývá výpočtovým modelováním kontrakce levé srdeční komory pomocí metody konečných prvků. Primárním cílem práce je vyhodnotit vliv blokády levého Tawarova raménka na ejekční frakci komory. Dále je vyšetřován dopad blokády na pohyby komory během srdečního cyklu, na lokální hodnoty přetvoření a na rozložení napětí ve stěně. Průběh elektrické aktivace jak zdravé komory, tak i komory s blokádou je modelován pomocí monodoménové rovnice svázané s pseudo-modelem buněčné membrány, který byl navržen za účelem snížení výpočetní náročnosti monodoménové rovnice. Rychlost šíření vzruchu v myokardu je uvažována ortotropní. Vypočítané časové průběhy elektrické aktivace ukazují, že blokáda levého Tawarova raménka prodlužuje dobu depolarizace komory o 50 %, což je v souladu s udávanými délkami trvání QRS komplexu na EKG u zdravých jedinců a u pacientů s blokádou. Průběhy elektrické aktivace jsou následně využity v simulacích kontrakce komory pro předepsání počátku kontrakce jednotlivých prvků sítě. Pasivní mechanická odezva myokardu je v těchto simulacích popsána pomocí ortotropního hyperelastického modelu. Aktivní napětí vyvolané svalovou kontrakcí je do modelu zahrnuto prostřednictvím časově závislého tenzoru aktivního přetvoření. Do počáteční konfigurace modelu, reprezentující stav komory na konci diastoly, je před zahájením kontrakce zahrnuto předpětí odpovídající end-diastolickému tlaku v komoře. Časový průběh komorového tlaku během ejekční fáze je modelován pomocí dvouparametrického modelu Windkessel. Výsledky simulací ukazují, že blokáda levého Tawarova raménka nesnižuje významně čerpací schopnost komory. Predikovaný pokles ejekční frakce v důsledku blokády činí pouze 2,3 %, což je v souladu s některými publikovanými klinickými výsledky. Vypočítané časové průběhy posuvů a přetvoření ve vybraných místech modelu taktéž vykazují některé charakteristiky popisované klinickými nebo experimentálními studiemi. V oblasti mezikomorového septa byly pozorovány výrazně vyšší hodnoty napětí než v ostatních částech komory; tyto výsledky však bude nutné ověřit dalšími výpočty, neboť v současném modelu není septum zatíženo silovými účinky vyvolanými kontrakcí pravé komory.
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Determination of residual stresses from strain field around drilled hole
Horák, Richard ; Návrat, Tomáš (referee) ; Halabuk, Dávid (advisor)
The master’s thesis focuses on determining homogeneous residual stresses using the hole-drilling method. The optical method of digital image correlation (DIC) is used for measuring released strains. In order to evaluate residual stresses using the entire strain field, it is necessary to know the functional dependencies of calibration constants on this field. Therefore, a significant part of the master’s thesis includes finding these dependencies in relation to the dimensions of the drilled hole and coordinates of the measured points. Another part of the thesis deals with the evaluation of homogeneous residual stresses based on provided experimental data obtained from the measurement of uniaxially loaded steel flat bar with a through-hole. At the end of the thesis, a sensitivity analysis is performed, which examines the influence of input variables in the calculation algorithm in relation to computed residual stresses.
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Deformation analysis of the bearing of the main shaft of the wind power plant
Doležel, Miroslav ; Pokorný, Jan (referee) ; Vosynek, Petr (advisor)
This work studies a load distribution in spherical roller bearings of a main shaft in a wind power plant. The effect of the shaft and bearing houses as flexible bodies is considered for a particular geometry. The data are collected and processed by numerical computational modelling using the finite element method. Several complexity levels of models are studied. These analyses are also compared with the data obtained from the software Mesys. The results show that an inclusion of a flexible bearing housing has the greatest effect on the load distribution in the internal geometry of the bearing. The load distribution is also dependent on the direction of the radial load force. The most complex models are dependent on the friction coefficient in the internal bearing geometry, thus revealing the problem of interactions among the bearings. Knowledge of the load distribution contributes to the design of more reliable rolling bearings.
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