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Computational modeling of 3D printing structures made of PET-G material
Michálek, Mojmír Cyril ; Halama, Radim (referee) ; Vosynek, Petr (advisor)
Master’s thesis deals with computational modeling of 3D printing process done by FDM method made from PETG material using finite element method. Research section contains a brief description of 3D printing process modeling possibilities using finite element method and summarizes fundamental mechanical properties of thermoplastics. In practical section there is an evaluation of specimens printed of PETG material tensile tests. Further there is performed a sensitivity analysis of various influences on vertical imperfection of printed part Idler and is done its design modification, which is based on results of this analysis.
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Stress-Strain Analysis of Plate for Fixing a Tibial Fracture Type I per Schatzer's Classification
Filková, Alena ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
Fractures of the proximal tibia are the most severe intra-articular fractures with subsequent frequent complications. In most cases, the fracture is treated with an inner plate or screws. This diploma thesis focuses on the stress-strain analysis of the plate fixed in the tibia using bone screws. Computational modeling using the finite element method was used to assess the mechanical interaction between the individual elements of this system. For this purpose, it was necessary to conduct a research study dealing with issues involving bone tissue, their damage and subsequent treatment of fractures. Stress-strain analysis was performed for two variants of fixation of this fracture: fixation with an angularly stable plate with screws and fixation with compression lag screws. Furthermore, these analyses were supplemented by their modifications, which represented different levels of these two variants of the computational model. Screws for fixing the plate in the bone tissue were considered both threaded and unthreaded. The interface between the screws and the bone tissue was solved using the Bonded contact and also the Frictionless contact. The influence of these modifications of the computational model on the resulting deformation and stress characteristics was assessed in the evaluation of the results. The mechanical interaction between the elements of this system was assessed in all performed variants.
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Analysis of Response Variables of Bone Tissue under Mechanical Loading
Vosynek, Petr ; Daniel, Matej (referee) ; Janíček, Přemysl (referee) ; Návrat, Tomáš (advisor)
Dissertation summarizes the results of computational and experimental modeling in the field of biomechanics engineering. Analyses are focused on selected variables that complement or can supplement existing methods of prediction of bone fractures. In terms of computational modeling the variables are based on stress strain analysis. The greater part of the work has been aimed on experimental modeling which is used for monitoring the two dominant components of bone tissue, which are minerals and collagen fibers. The current most widely used variable for the description of bone loss (osteopenia, osteoporosis) is areal bone mineral density (BMD). This variable does not however provide any information about the change in total volume consequently change of mineral and collagen. Proposed mechanical values follow the loss of the two components during simulation of minerals loss (demineralization) and simulation of collagen loss (deproteinization) in vitro for long turkey bones
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Influence of calcifications on stress states in arteries
Macůrek, Michal ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
The first part of this thesis covers anatomy of blood vessel walls, their material characteristics and their computational modeling. Second part is focused on determining the influence of calcifications on stress states in common carotid artery. In the rest of the thesis, models of plate calcification and spheical calcifications distributed in the circumferential and axial directions of the artery are compared.
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A research study of plate for the treatment of tumorous mandible
Mäsiar, Matúš ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
This bachelor’s thesis aims to address the issue of treating tumorous conditions in the lower jaw by implementing a reconstructive plate. The thesis includes an examination of basic anatomy related to the specific problem, along with a research study on the utilization of reconstructive plates based on available literature. Subsequently, a stress-strain analysis of the lower jaw with the two different applied reconstructive plates was performed using computational modeling, specifically employing the finite element method within ANSYS Workbench 22.2. The thesis provides a detailed description of the creation of two variations of the computational model, followed by an evaluation of the stress and deformation exhibited by the system.
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Computational modeling of arterial stents
Ondříšková, Tereza ; Hrubanová, Anna (referee) ; Fischer, Jiří (advisor)
This thesis deals with computational modeling of self-expandable and balloon-expandable arterial stents. The introductory part of the thesis is devoted to a brief overview of basic medical knowledge related to the circulatory system and cardiovascular diseases. Then, a review of constitutive models of soft tissues and arterial stents is processed, including their historical development, classification, and materials used for their production. An experimental tensile test of a nitinol wire is also included, based on which a constitutive model describing the behavior of shape memory alloys is selected. The main part is focused on the computational modeling of the interaction between an artery affected by an atherosclerotic plaque with a nitinol self-expanding stent and with a steel balloon-expandable stent. An analysis of radial displacements on the artery model wall and resulting stress states is carried out. Finally, these two approaches are compared in terms of the enlargement of the cross-sectional area of the given artery.
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Stress-Strain Analysis of Plate for Fixing a Tibial Fracture Type I per Schatzer's Classification
Filková, Alena ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
Fractures of the proximal tibia are the most severe intra-articular fractures with subsequent frequent complications. In most cases, the fracture is treated with an inner plate or screws. This diploma thesis focuses on the stress-strain analysis of the plate fixed in the tibia using bone screws. Computational modeling using the finite element method was used to assess the mechanical interaction between the individual elements of this system. For this purpose, it was necessary to conduct a research study dealing with issues involving bone tissue, their damage and subsequent treatment of fractures. Stress-strain analysis was performed for two variants of fixation of this fracture: fixation with an angularly stable plate with screws and fixation with compression lag screws. Furthermore, these analyses were supplemented by their modifications, which represented different levels of these two variants of the computational model. Screws for fixing the plate in the bone tissue were considered both threaded and unthreaded. The interface between the screws and the bone tissue was solved using the Bonded contact and also the Frictionless contact. The influence of these modifications of the computational model on the resulting deformation and stress characteristics was assessed in the evaluation of the results. The mechanical interaction between the elements of this system was assessed in all performed variants.
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Computational modeling of the interaction of flowing blood with the artery tube with the atheroma
Freiwald, Michal ; Jagoš, Jiří (referee) ; Švancara, Pavel (advisor)
Předložená diplomová práce se zabývá interakcí mezi proudící krví a krční tepnou, obsahující aterosklerotický plat, za pomoci konečnoprvkové fluid-structure interaction analýzy. První část práce obsahuje souhrn teoretických poznatků, sestávající z kardiovaskulárního systému, cév, souvisejících konstitutivních modelů, reologie krve a úvodu do teorie proudění. Dále je v práci obsažen stručný souhrn současného poznání výpočtového modelování v této oblasti, s důrazem na strukturní a fluid-structure interaction analýzy v oblasti krční tepny, a na použité konstitutivní modely. Experimentální část se soustředí na tvorbu zjednodušeného modelu krční tepny, obsahující aterosklerotický plat, a na tvorbu odpovídajícího modelu krve. Oba modely poté společně vstupují do fluid-structure interaction analýzy, která si klade za cíl pochopit důsledky pulzujícího toku krve na stěnu tepny a na růst aterosklerotického plátu; primárními zkoumanými veličinami jsou první hlavní napětí na stěně tepny, celková deformace stěny tepny, časově zprůměrovaná hodnota smykového napětí na stěně tepny a oscilační smykový index. Všechny výsledky jsou porovnány napříč několika typy analýz, tak aby bylo možné zhodnotit rozdíly a důsledky zvoleného přístupu. Součástí práce je také zjednodušená parametrická studie, která porovnává vliv rostoucího procenta stenózy na vyhodnocované veličiny. V poslední částí práce jsou zhodnoceny výsledky, její limitace a další možnosti výzkumu v této oblasti.
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Computational modelling of mechanical tests of animal cell
Orlová, Lucie ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
Předkládaná diplomová práce se zabývá stavbou živých živočišných buněk a jejich odezvou na mechanické zatěžování. Zobecněným zaměřením práce je popis mechanického chování buňky nejenom ve fyziologickém, ale i v patologickém stavu. Výchozím předpokladem pro úspěšné řešení zadané úlohy je vysoce interdisciplinární přístup kombinující výpočtové přístupy mechaniky těles (v~tomto případě metodu konečných prvků) s lékařským výzkumem. Nejdůležitějším bodem při tvorbě výpočtového modelu, pomocí něhož je možné aproximovat chování živé buňky při zatížení, je zejména identifikace mechanicky významných komponent a~jejich materiálových parametrů. V tomto případě jsou jako mechanicky význačné identifikovány spojité součásti jádro, membrána a cytoplazma, které jsou nově propojeny s prvky diskrétními (mitochondriální sítí) v hybridním modelu, jehož platnost je ověřena pomocí experimentálních dat. Tento model slouží jako podklad k vyhodnocení míry vlivu mitochondrií na celkovou tuhost buňky.
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Modelling of pressure equipment bolted flange connections
Kolátor, Matyáš ; Pernica, Marek (referee) ; Létal, Tomáš (advisor)
The bachelor thesis deals with computational modeling of flange connections. Due to its separability, bolted flange connections are a frequently used in piping systems or pressure vessels. For the right functionality of the connection, it is necessary to ensure the required tightness. In order to be able to describe the tightness, it is necessary to know the stresses and deformations in all parts of the connection. These days, standard calculation methods are at a high level of accuracy, on the other hand, in order to achieve this accuracy, they have to follow a lot of corrections, in which the original model based on the strength of material theory should be lost. The aim of bachelor thesis is to create computational models based on the strength of materials theory. Computational models are created to illustrate the application of strength of materials theory. At the end of the thesis, the results using several models will be summarized and compared.
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