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Modelling of viscoelastic materials with temperature dependence
Miloš, Vojtěch ; Hron, Jaroslav (advisor) ; Tůma, Karel (referee)
Materials such as asphalt, polymers or the Earth's crust tend to behave in a way that can be described neither with a model of viscous fluid, nor a model from solid mechanics. There are indeed models capable of capturing these so called viscoelastic phenomena far better, but they are based on the presumption of constant temperature. In many cases, e.g. in the glass industry or in geophysics, the properties of a viscoelastic material strongly depend on temperature. That is why it is precisely these changes that need to be described. There are viscoelastic models used in practice that take into account the material parameters' dependence on temperature, however, they do not consider the viscoelastic nature of the material when describing the temperature evolution. The objective of this thesis is to derive thermodynamically consistent viscoelastic models with temperature dependent parameters and the appropriate evolution equation for temperature, implementation of the models and computing simple test simulations. Powered by TCPDF (www.tcpdf.org)
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Modelling of viscoelastic materials with temperature dependence
Miloš, Vojtěch ; Hron, Jaroslav (advisor) ; Tůma, Karel (referee)
Materials such as asphalt, polymers or the Earth's crust tend to behave in a way that can be described neither with a model of viscous fluid, nor a model from solid mechanics. There are indeed models capable of capturing these so called viscoelastic phenomena far better, but they are based on the presumption of constant temperature. In many cases, e.g. in the glass industry or in geophysics, the properties of a viscoelastic material strongly depend on temperature. That is why it is precisely these changes that need to be described. There are viscoelastic models used in practice that take into account the material parameters' dependence on temperature, however, they do not consider the viscoelastic nature of the material when describing the temperature evolution. The objective of this thesis is to derive thermodynamically consistent viscoelastic models with temperature dependent parameters and the appropriate evolution equation for temperature, implementation of the models and computing simple test simulations. Powered by TCPDF (www.tcpdf.org)
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Visualization of computed flows using particle tracing methods
Miloš, Vojtěch ; Hron, Jaroslav (advisor) ; Kučera, Václav (referee)
A mesh of tetrahedrons is build from a real data that were obtained by CT (computer tomography) or MRI (magnetic resonance imaging) scan of a blood vessel and then velocity vectors are computed in every vertex using the nite element method. The objective of the work is to design and implement a particle tracing algorithm in such a mesh with an emphasis on a maximum accuracy of the result. For this purpose, an analytic integration method is presented, which can be used thanks to piecewise linear vector eld. We propose our own modi cation of this method and compare its results with the conventional numerical integration. Furthermore, the work describes modi cations of common step methods that are used to determine the cell that contains a particular particle without the need to search the whole mesh in each step. Powered by TCPDF (www.tcpdf.org)
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