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Stability analysis of swinging props turbines
Bukovský, Petr ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
Master thesis deals with a computing simulation of two props turbines lines. The thesis output is gaining maximum possible load, at which a commencement of deformation stability critical state for various geometrical imperfections has not arisen yet. The calculation has been done by FEM in two different ways: linear solution (using a calculation conversion into eigenbuckling) and nonlinear solution (using a FEM deformation option). Result analysis compares both methods outcomes. Safety factor for the props operation has been proposed taking into consideration known influences on operating state.
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Stress and strain analysis of different total knee endoprostheses on tibia bone tissue performance
Boháč, Petr ; Borák, Libor (referee) ; Marcián, Petr (advisor)
This diploma thesis deals with the stress-strain analysis of the influence of various total knee endoprosthesis on the periprosthetic bone tissue of the tibia. The first part of the thesis describes the problem situation and the research study related to the issue. The second part of the thesis describes the basic knowledge suitable for understanding the issues addressed. The third part of the thesis describes in detail the process of creating computational models, which should make the used methodology reproducible for possible further studies. The next part of the work analyses and presents the results of computational modelling using the finite element method. Based on the Frost hypothesis, the effects of various total knee endoprosthesis on the periprosthetic tibial bone tissue at a specified maximum load appearing in the walking cycle are evaluated and compared. At the end of the thesis, the possible consequences of this analysis are mentioned.
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Vibration Propagation Analysis of Coupled Structure Acoustic Space
Kostelník, Jan ; Pellant, Karel (referee) ; Novotný, Pavel (advisor)
The aim of this Master’s thesis Vibration Propagation Analysis of Coupled Structure Acoustic Space is to analyze vibration propagation in combustion engine, from combustion space through solid structure to fluid surroundings. Then analyze the noise increase as pressure changing in fluid space around the solid structure. There was made a analyze of single piston engine in different frequency and piston location. A simulation of distribution of a pressure waves was made in an ANSYS application.
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Methods of fixation of the upper limb fractures
Litera, Jan ; Marcián, Petr (referee) ; Florian, Zdeněk (advisor)
The presented bachelor thesis is focused on current methods of a fixation of upper limb fractures. Part of the thesis is a literature review and a description of the upper limb anatomy. This is necessary to solve the problems associated with upper limb fractures. The history of the treatment of upper limb fractures enables to gain an insight and a benefit of the current methods of the fixation of the upper limb. Based on the acquired knowledge, there is created a simple computational model of a humeral fracture fixation using a LCP and a classical plate. The computational model for the specific load models was solved in the Ansys Workbench 18.2 computing system. The biomechanical analysis based on the results presentation of the solution of the described simple model showed differences between the application of the LCP and the classical plate.
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Analysis of residual stresses in arterial wall
Novák, Kamil ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
This thesis deals with computational modeling of the influence of residual stresses in idealized geometry of blood vessels and subsequent application of acquired knowledge to abdominal aortic aneurysm. In the terms of quality of the computational model, we reduced the uncertainties that are included in the computational model without considering the influence of residual stresses. The basic assumption of homogenization significant peaks of the stress between inner and outer vessel wall was met for each level of the computational model Methods that have been used are: deformation method (opening angle method), inverse mechanics of large deformations, fictitious temperature – for linear elastic material and hyperelastic material defined by the constitutive model. Numerical verification was carried out using program ANSYS.
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Quantification of Hydraulic Descaling Mechanisms
Hrabovský, Jozef ; Toman,, Zdeněk (referee) ; Dobeš, Ferdinand (referee) ; Horský, Jaroslav (advisor)
The issue of descaling is an important part of the forging and heat treatment of steel and semi products of steel production. Rising of new information and study of this process can increase efficiency and improve the surface quality after descaling. This thesis is focused on the mechanisms of the high pressure hydraulic descaling qualification and study of the chemical compounds of which the scales grown. To achieve all goals of this work and to get a comprehensive view of descaling process, few experimental measurements and numerical analyses were performed. All experimental measurements were focused on obtaining data about fundamental parameters and effects of the hydraulic descaling. The data obtained from measurements were applied to numerical analyses, which aimed to discover a deeper relation and to confirm the experimental results. This thesis can be divided into two main parts. The first part is devoted to parameters of the water jet study. The main studied characteristics of the high pressure hydraulic water jet were heat transfer coefficient and impact pressure at different modes such as standard or pulsating water jet. Experimentally measured data of these parameters were applied in numerical analyses. The numerical analyses were focused on studying the impact of the water jet parameters on the stresses in the oxide scale layers. A further water jet analysis was focused on the influence of the individual parts of the hydraulic system (such as water chamber or stabilizer) on its characteristics. In this part different types of the water chambers in combination with different types of stabilizers on the impact pressure values were investigated. These measurements were supported by fluid flow analysis through the hydraulic system. The second part of this work was focused on getting mechanical properties of the oxide scales from specimens prepared from standard structural steel and specimens from silicon steel. In this thesis, the influence of various parameters and characteristics was studied on these two types of steel. Mechanical properties of oxide scale structures were carried out by the Small Punch Test method. To obtain the fundamental mechanical properties such as Young´s modulus, yield strength and ultimate strength, material parameters based on the measured data were optimized. The whole work was carried out in order to get valuable and comprehensive results about high pressure hydraulic descaling process and influencing factors as well as about oxide scales themselves.
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Deformation and stress analysis of the parts of the total replacement of the trapeziometacarpal joint
Svojanovský, Tomáš ; Marcián, Petr (referee) ; Fuis, Vladimír (advisor)
The presented diploma thesis builds on author’s bachelor’s thesis of the similar name which was focused, in particular, on rhizarthrosis. Because of this joint disease, implantations of the total joint replacement are performed. The bachelor’s thesis also served as a familiarization with the finite element method and contact analyses issues, giving a theoretical framework for this diploma thesis. As opposed to that, the diploma thesis aims entirely at deformation and stress analysis of the total replacement. The main objective is to carry out analyses of different variants of geometric models. In addition, there is a tendency to analyze contact pressures of advanced model concerning all the total replacement, bone tissues, ligaments and tendons guaranteeing the static equilibrium of components. The bachelor’s thesis has been developed in ANSYS Workbench, whereas the diploma thesis in ANSYS APDL. Work in APDL allows user to control better over the entire computational process, however, requires more skills and theoretic knowledge. Contact analyses bring a lot of problems associated with convergence of procedures and accuracy of results. Therefore, explanations of important terms and set of recommendations are included for the purpose of easier solving of the contact problems.
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Use of Retomo software for computational modeling in biomechanics
Filková, Alena ; Lisický, Ondřej (referee) ; Marcián, Petr (advisor)
This bachelor thesis deals with the issue of musculoskeletal biomechanics. More precisely, of creating a geometry model based on CT data using the RETOMO program and then a computational model. The introductory part is devoted to a brief explanation of the concepts of computed tomography and finite element methods. The following chapter provides a search of programs used to create models of geometry from CT data in biomechanics. Furthermore, the work deals with the description of selected functionalities and user environment of the RETOMO program, with the greatest emphasis on the creation of a geometry model from CT data. During the implementation of the bachelor's thesis, two models of geometry were created in the analysed program, using different segmentation functions, which were then compared with each other and then compared with a model of geometry created in another program. The GOM Inspect program was used to compare the geometry deviations of individual models. Finally, computational models were created using the CATIA program and then deformation and stress analysis was performed using the ANSYS program. The results of individual solutions were analysed, compared and evaluated.
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Evaluation of elastic parameters for models of isolated cells
Krbálek, Jaroslav ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
This diploma thesis focuses on computational modeling of the cell mechanical tests. The goal of this thesis is to build a cell model and to simulate compression test on this model. If necessary, the model should be adjusted so the model reflects real cell behavior. It was created the cell model reflecting cytoplasm, nucleus, membrane and cell cytoskeleton. Cytoskeleton was modeled as tensegrity structure. After this, the pressure test was simulated on this model. The behavior of the cell model and real cell was compared using the stress force. The stress force - cell deformation curve was markedly different for the cell model and the real cell. For this reason, the cytoplasm material model was adjusted. The difference between the curves was acceptable after this modification. It was found during computations that the cytoskeleton model influence on the cell load is minimal. These results does not reflects real cell behavior, which means that the model is considered inadequate for performing stress load simulation.
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Literature search of possibilities of computational modelling of brain aneurysms
Lipenský, Zdeněk ; Polzer, Stanislav (referee) ; Burša, Jiří (advisor)
This bachelor thesis is focused on gathering general information about a cerebrovascular disorder called Cerebral Aneurysm (or also Brain Aneurysm) which is a medical condition consisting in an abnormal bulging outward of one of the arteries in the brain. The initial attention is given to the human cardiovascular system, a description of which is fatal for understanding the problem of brain aneurysm. The next attention is focused on the solution of eliminating the tension within the aneurysm by using knowledge gained in lectures "Flexibility and Strength II" during the sixth semester. The last chapter shows a summary of three works dealing with computational modeling of cerebral aneurysm.
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