Original title: Výpočet pravděpodobnosti porušení keramické hlavice endoprotézy s tvarovou odchylkou
Translated title: Calculation of the probability of the endoprosthesis ceramic head with shape deviation
Authors: Kučerková, Miroslava ; Fuis, Vladimír (referee) ; Kovář, Jaroslav (advisor)
Document type: Master’s theses
Year: 2022
Language: slo
Publisher: Vysoké učení technické v Brně. Fakulta strojního inženýrství
Abstract: [slo] [eng]
Hlavnou náplňou diplomovej práce je určenie pravdepodobnosti porušenia keramickej hlavice endoprotézy bedrového kĺbu za predpokladu trojosového stavu napätosti. Pre jej stanovenie sú potrebné tri hlavné napätia určované pomocou metódy konečných prvkov. Keramické materiály, endoprotézy bedrového kĺbu a Weibullovu teóriu najslabšieho článku, ktorá popisuje výpočet pravdepodobnosti porušenia keramických súčastí, chronologicky približuje rešeršná časť práce, po ktorej nasleduje výpočtová časť. Prvý z modelov, pre ktorý bola napätosť a pravdepodobnosť porušenia určovaná, je valcové teleso. Rozloženie napätia v ňom bolo určované numericky, ale aj analytickým spôsobom. Jeho primárnym účelom je teda overenie vytvoreného algoritmu pre výpočet pravdepodobnosti porušenia použitom pri výpočtoch hlavice endoprotézy. Takisto tu bola overená vhodnosť využitia spriemerovaných hodnôt napätia. V ďalšej časti práce bol počítaný model ideálnej keramickej hlavice. Analyzovaný bol vplyv trenia, penetrácie a citlivosti siete modelu. Zhodnotené poznatky boli v práci následne využité pri výpočtoch modelu hlavice s imperfekciou typu ovalita, ktorej vplyv na výslednú pravdepodobnosť porušenia v porovnaní s ideálnym stavom bol v závere zhodnotený. The main content of the diploma thesis is to determine the probability of failure of the hip joint endoprosthesis ceramic head. The assumption is the three-axis state of stress. To calculate the probability of failure three principal stresses, which are determined numerically using finite element method, are needed. Ceramic materials, hip joint endoprosthesis and Weibull weakest link theory, which describes the calculation of the probability of failure of ceramic components, are described in the first part of the thesis, after that, the second part with calculations follows. The first model, for which the stress and probability of failure were calculated, is a cylindrical body. The stress distribution in it was determined numerically as well as analytically. Its primary goal is to verify the developed algorithm of calculating the probability of failure. This algorithm is also used in calculations of probability of failure of ceramic femoral head. The suitability of using averaged principal stress values was also verified here. In the next part of the thesis, a model of an ideal ceramic head was created and its probability of failure was calculated. The impact of friction, penetration and the size of elements used for discretization of the model on the value of probability of failure were all analysed. The evaluated findings were subsequently used in the calculations of the model of ceramic head with an deviation from the ideal ovality. The impact of this change on the resulting probability of failure in comparison with the ideal state was evaluated in the conclusion.
Keywords: ceramic head of the endoprosthesis; ceramic materials; deviation from ideal ovality; probability of failure; Weibull weakest link theory

Institution: Brno University of Technology (web)
Document availability information: Fulltext is available in the Brno University of Technology Digital Library.
Original record: http://hdl.handle.net/11012/206145

Permalink: http://www.nusl.cz/ntk/nusl-503719


The record appears in these collections:
Universities and colleges > Public universities > Brno University of Technology
Academic theses (ETDs) > Master’s theses