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Numerical simulation of failure of ceramic foams upon mechanical loading
Hanák, Jiří ; Skalka, Petr (referee) ; Ševeček, Oldřich (advisor)
The master’s thesis deals with a numerical simulation of failure of ceramic foams with open-cell structure and with understanding of conditions required for the failure of the structure under various mechanical loading conditions. To this purpose, the so-called stress-energy coupled criterion was utilized. The motivation for this thesis was to create a model able of the most accurate prediction of the ceramic foam strength in comparison with experimental observations. First part of the thesis is focused on the theoretical background required for solving the problem. More specifically there are mentioned methods of the foam material modelling, Linear Elastic Fracture Mechanic (LEFM) and coupled stress-energy criterion used for definition of the crack initiation. In the second part of the thesis, numerical Finite Element Analyses (FEA) whose main purpose was to determine critical conditions necessary for the initiation of strut failure within the foam structure, were performed. These pieces of knowledge were then used for creation of the numerical simulation algorithm of the mechanical test of foam material with regular cell pattern. Outputs of numerical simulations were at the end of this work compared with experimental results (of the compression test) made on the real Al_2 O_3 foams prepared by 3D printing technology and provided by the Institute of Physics of Materials Czech Academy of Science. It can be concluded that a good agreement between results of both approaches was reached and the prediction of the ceramic foam mechanical strength using the developed model is in the meanwhile the most accurate estimation from recently published approaches.
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Design of laminate handlebars for mountain bikes
Hanák, Jiří ; Ševeček, Oldřich (referee) ; Polzer, Stanislav (advisor)
This bachelor’s thesis describes design of laminate handlebars for mountain bikes. The first part describes the mechanical properties of composite materials, with the emphasis on fiber composites. The algorithm for acquiring material characteristics of fiber composite by analytical method is presented. In the next part, it is shown how to control the direction of fibers in lam-inate in the finite element calculations and its impact to resulting stresses in the material. The aim of the last part is design geometry model of laminate handlebars for mountain bikes with following stress – strain analysis by FEM and software ANSYS. The analysis is performed for static loading.
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Sino-american economic relations at the begining of the 21st century and their impact on the world economy.
Hanák, Jiří ; Neumann, Pavel (advisor) ; Němcová, Ingeborg (referee)
The thesis deals with sino-american economic cooperation with the emphasis on the period after 2000 and the current situation. The objective was to evaluate these relations and to analyse selected problems associated with the international trade. The thesis is dividend into six chapters. First two deal with general description of both economies and short summary of up to date relations. The third chapter concentrates on the structure of mutual trade and investment, with the emphasis on the concentration of foreign exchange in present China and its role in the U.S. federal debt. The fourth chapter targets three selected problems -- mutual cooperation within the WTO and the existing trade barriers, current Chinese exchange rate policy and the problem of unemployment and open economy. The fifth chapter targets the international trade theory, especially sustainability of long term deficit in the current account, problem of foreign debt and international investment position. The last chapter is handling with the impact of USA and China on the imbalance in the world economy and changes associated with the rise of China as the second-largest world economy.
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Selected Topics of the Common Agricultural Policy of European Union - the impact of the Czech agricultural sector
Hanák, Jiří ; Štěňhová, Božena (advisor) ; Nigrinová, Lenka (referee)
Práce se zabývá Společnou zemědělskou politikou Evropské unie a změnami, které přinesla českému zemědělství. První část se věnuje obecně tématu Společné zemědělské politiky, druhá část je zaměřena na zemědělství české. Jeho specifika, období před a po vstupu do Unie. Obecně je charakterizována změna dotačního systému, agrárního trhu a agrárního zahraničního obchodu. Podrobněji rozebrána jsou aktuálně krizová odvětví výroby cukru, lnu a vepřového masa. Poslední část se věnuje perspektivám českého a evropského zemědělství v podobě ekologického zemědělství, biopaliv a geneticky modifikovaných organismů.
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