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Assessment of impact of arrangement of collagen fibres in arterial wall on its response in tension tests
Kratochvíl, Filip ; Chamrad, Jakub (referee) ; Burša, Jiří (advisor)
This thesis deals with organisation of collagen fibres in human blood vessel walls and with simulation models, which are used to calculate vessel behaviour. Firstly, the thesis focuses on the anatomy of human blood vessel system, mainly on the vessel structure and properties of some vessel components. Next, two models are presented, which can be used for the vessel wall in calculations, specifically models with straight and wavy collagen fibres. Moreover, some methods are described, which can be used to gain information about a vessel. Subsequently, relationships are derived needed for simulation of tension tests of these models, mainly to express the length of collagen fibres. In the practical part simulations of vessel behaviour during uniaxial tension test are carried out and histograms of local direction angles of collagen fibres in the unloaded state are created. In the end, results gained by simulations are compared with real available data.
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Stress-Strain Analysis of Plate for Fixing Proximal Tibial Fracture
Votava, Tomáš ; Chamrad, Jakub (referee) ; Marcián, Petr (advisor)
This master thesis is focused on stress-strain analysis of tibia with fixed proximal tibial fracture. Two types of fixation were considered, for each one two variants of solution were made. In the first part of this theses is presented a review of available literature connected with stress-strain analysis of tibia with fixed proximal tibia fracture. Next one is presented a research study of anatomy and biomechanics focused on lower limb. In the last part of research part are presented proximal tibial fractures and way of their fixation. Computational modeling using finite element method was used as solution method of stress-strain states. ANSYS software was used for solution. Total displacement, contanct pressure between femoral articular surface and meniscus, stress on plate and screws and strain in tibial bone tissue were analysed. Assesment of bone tissue state was made on the basis of Frost's hypothesis.
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A COMPARISON OF THE WATER JET CUTTING AND LASER TECHNOLOGIES
Chamrad, Jakub ; Zlámal, Jan (referee) ; Píška, Miroslav (advisor)
The thesis is focused on the introduction of non-conventional technology into the manufacturing workplace, mainly water jet and laser cutting. The first two chapters are research about water jet machining and laser. A practical part of my thesis was carried out with the assistance of Honeywell and involved comparing the efficiency of an older laser cutting machine against and new one for water jet machining.
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Assessment of surface roughness and its influence on fatigue life
Dziubek, Jan ; Chamrad, Jakub (referee) ; Horníková, Jana (advisor)
This thesis deals with influence of surface roughness on fatigue life. In the thesis, the evaluation of the surface roughness by the profile method according to the standard ČSN EN ISO 4287 is specified. Within the work, the roughness parameters of samples with different surface treatment were determined. Then, SN-curves were drawn for samples with different surface treatments and compared with each other.
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Biomechanical Study of Cranial Implants
Chamrad, Jakub ; Henyš,, Petr (referee) ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
Tato práce s názvem Biomechanická studie lebečních implantátů se zabývá především výpočtovým modelováním jak nepoškozené lebky, tak i lebky s defektem a lebečním implantátem. Přístup řešení pro vyhodnocování deformačně-napěťových stavů systému lebka-implantát-fixační prvky byl prováděn pomocí výpočtového modelování metodou konečných prvků. Pro validní analýzy a interpretaci výsledků je třeba zvolit vhodnou úroveň výpočtových modelů. Výběr úrovně výpočtového modelu je z tohoto důvodu zásadním problémem, kterému jsou věnována značná část této práce. Bylo prokázáno, že volba úrovně má přímý vliv na hodnoty zkoumaných biomechanicky významných parametrů. Dalším faktorem, který ovlivňuje chování lebečního implantátu a jeho funkčnost, je rozměrová přesnost vyrobené kostní náhrady. Bylo pozorováno, že i malá rozměrová odchylka může způsobit změnu deformačně-napěťových stavů na lebce se zavedeným implantátem a způsobit tak rizikovou situaci z pohledu selhání implantátu nebo jeho fixace. Především způsob fixace implantátu bývá rizikový a snižuje spolehlivost implantátu. Je proto vhodné se na tuto oblast zaměřit a navrhnout možné způsoby zlepšení stávajících postupů nebo navrhnout nové způsoby fixace. Jedním ze zlepšení metody fixace implantátu k lebce může být použití hydroxyapatitového potahu na kontaktním rozhraní kost-implantát. To by mělo vést k oseointegraci, což je požadovaný efekt, který byl v této práci výpočtově modelován a vyhodnocován.
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An analysis of the influence of geometric variability of total hip endoprosthesis shank on stress-strain states in the hip joint
Zýbal, Jan ; Chamrad, Jakub (referee) ; Marcián, Petr (advisor)
This master's thesis deals with stress-strain analysis of hip joint after total hip replacement. These stress-strain states are compared between four variable stems. A research study of available literature is presented with the focus on finite element analysis of hip joints. Basics of hip's joint anatomy is described along with total endoprostheses' variants and properties. Computational modeling was chosen as a solution method using finite element analysis. The solution was executed using ANSYS software. For each stem there was created a computational model which consists of several submodels such as model of geometry, material, contacts and loading. The assesed variables were total hip displacement, contact pressure between the head and liner, stress on each stem and strain on femur. The evaluation of femur's bone tissue was accomplished on basis of Frost's mechanostat in seven Gruen zones.
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Biomechanical analysis of bone implant contact for different type of implant profiles
Svobodová, Miriam ; Chamrad, Jakub (referee) ; Marcián, Petr (advisor)
This bachelor thesis deals with the assessment of the influence of the dental implant diameter placed in the bone with a fixed connection between the bone and the given implant on the strain into the bones around the implant,the deformation throughout the system and the stress in the implant. Computational modeling with finite element analysis was used to solve a given task. Two types of the implants with different diameters and bone model with a beam structure and different layer thickness around the implant were modeled. Used material was homogeneous, isotropic and linearly flexible. The overall analysis was carried out at the 2D level. The results show different values for different diameters and thickness of the layers.
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Stress-strain analysis of cranial fixators
Klištinec, Dávid ; Chamrad, Jakub (referee) ; Marcián, Petr (advisor)
Zranenia hlavy si často vyžadujú lekársku starostlivosť, pri ktorej dochádza k stabilizácii alebo náhrade poškodeného tkaniva. Pre tento účel slúži kranioplastika, ktorá prinavracia pacientovi ochranný a kozmetický výsledok. Výber správneho materiálu kraniálneho implantátu je veľmi podstatný. Naviac potrebuje správny druh fixácie, ktorá ho udrží na mieste a predíde sa tak nedovolenému pohybu implantátu počas bežného života pacienta. Táto práca analyzuje deformačné a napäťové stavy dvoch druhov fixačných plátov prichytených na PMMA implantáte a ich mechanickej odozvy na rozličné záťažné podmienky spôsobené rôznymi stavmi kraniálnej hypertenzie a silou pôsobiacou na sústavu z exteriéru.
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Stress and strain analysis of skull implant
Chamrad, Jakub ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
To, jak se bude implantát chovat v lebce, je velmi důležitým faktorem, který ovlivňuje jeho funkci. K ovlivnění dochází především vnějšími silami a nitrolebečním tlakem. Tato zatížení mohou způsobit pohyb implantátu a poškození živých tkání. Tato práce shrnuje poznatky a analýzy, týkající se rekonstrukce poranění lebky. Srovnání implantátů z různých materiálů a fixátorů je založené na napěťově-deformační analýze implantátu, zatíženého vnějšími silami a nitrolebečním tlakem.
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Stress-Strain Analysis of Plate for Fixing Proximal Tibial Fracture
Votava, Tomáš ; Chamrad, Jakub (referee) ; Marcián, Petr (advisor)
This master thesis is focused on stress-strain analysis of tibia with fixed proximal tibial fracture. Two types of fixation were considered, for each one two variants of solution were made. In the first part of this theses is presented a review of available literature connected with stress-strain analysis of tibia with fixed proximal tibia fracture. Next one is presented a research study of anatomy and biomechanics focused on lower limb. In the last part of research part are presented proximal tibial fractures and way of their fixation. Computational modeling using finite element method was used as solution method of stress-strain states. ANSYS software was used for solution. Total displacement, contanct pressure between femoral articular surface and meniscus, stress on plate and screws and strain in tibial bone tissue were analysed. Assesment of bone tissue state was made on the basis of Frost's hypothesis.
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