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Verification of nonlinear material models of concrete
Král, Petr ; Němec, Ivan (referee) ; Hradil, Petr (advisor)
Diploma thesis is focused on the description of the parameters of nonlinear material models of concrete, which are implemented in a computational system LS-DYNA, interacting with performance of nonlinear test calculations in system LS-DYNA on selected problems, which are formed mainly by simulations of tests of mechanical and physical properties of concrete in uniaxial compressive and tensile on cylinders with applying different boundary conditions and by simulation of bending slab, with subsequent comparison of some results of test calculations with results of the experiment. The thesis includes creation of appropriate geometric models of selected problems, meshing of these geometric models, description of parameters and application of nonlinear material models of concrete on selected problems, application of loads and boundary conditions on selected problems and performance of nonlinear calculations in a computational system LS-DYNA. Evaluation of results is made on the basis of stress-strain diagrams and load-displacement diagrams based on nonlinear calculations taking into account strain rate effects and on the basis of hysteresis curves based on nonlinear calculations in case of application of cyclic loading on selected problems. Verification of nonlinear material models of concrete is made on the basis of comparison of some results of test calculations with results obtained from the experiment.
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Virtual modelling of computional domain for CFD simulations
Volek, Matěj ; Naď, Martin (referee) ; Dohnal, Miloslav (advisor)
This thesis is devoted to open-source software for meshing in CFD simulations. In the opening chapter, there is introduced the computational modeling of fluid, briefly described governing equations and an introduction to the discretization of computational domain. The second chapter deals with the available mesh software. The programs are described in this chapter from the perspective of the user interface, the ability to create meshes, etc. The last chapter, there is a comparison of two selected programs on a real problem. In both programs was created a mesh which was calculated in the software Fluent. Then the calculation results are compared.
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Simplified computer models of elements for an air distribution
Mishuk, Aliaksandra ; Gebauer, Günter (referee) ; Šikula, Ondřej (advisor)
The goal of this master thesis is to create a simplified model of an actual swirl diffuser using CFD (Computational Fluid Dynamics) simulation, so that it would be easy to calculate (would have a simple geometry, a proper mesh and would enable quick definition of the model’s boundary conditions) and would also create an airflow pattern in space as close to reality as possible. In the process a CFD model with a certain geometry was created. Subsequently, various model settings were tested. Calculation results were compared with the results of the experimental measurement done using the PIV method.
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Change of magnetic susceptibility during the germination of plants
Sedlář, Petr ; Fiala, Pavel (referee) ; Vlachová Hutová, Eliška (advisor)
The work examines the changes in the magnetic susceptibility during the early germination of the somatic embryo (RSE) of the Norway spruce. Susceptibility is in the physically view the property, which can be used to determine a variety of parameters and properties of the measured objects. The aim of this work was to create a automatic to evaluate the susceptibility of the tissue RSE and take measurements to prove or disprove the contrary of the accuracy of this assessment. This work contains the results obtained by modeling a script in Matlab, in which can be shown the correctness of the theoretical concepts.
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Simulation of toroid coils in Ansoft Maxwell 3D
Daněk, Michal ; Pfeifer, Václav (referee) ; Hanák, Pavel (advisor)
The master thesis is focused on the simulation of the toroid coils in Ansoft Maxwell 3D software, which uses finite element method for electromagnetic field simulation. Firstly the process creation of the geometric model toroid coil with seventy-five threaded is presented. It is necessary to debug this model and prepare it for the mesh generation. Physical properties are assign to this model and it gives rise to the physical model. We will set boundaries, excitation current, core material, winding material and the parameters for the mesh generations. New material Kashke K4000 will be created in the materials library and subsequently we will define its BH curve on the basis of datasheet. Analysis is made in two modes. Direct currents (7,5A; 10A; 15A; 20A; 25A) and (non)linear materials are used in magnetostatic solution. Toroid coil is excited by current pulse in transient solution. In Ansoft Maxwell Circuit editor a source which generates current pulse will be created. This excitation will be assigned to the toroid coil as an extern source through a terminal. Core material is linear in the case of transient analysis, because Ansoft Maxwell 3D doesn´t allow to use nonlinear material in this solution. Settings are different in transient and in magnetostatic analysis. End time and time step are entered to solve this task in transient analysis. Time points are entered too. Flux density and electromagnetic field strength are calculated in these time points and later it will be possible to view the results. Calculated fields are shown as the pictures in this thesis. The procedure how to use a field calculator in the postprocessing is given as well. The achievements are summarized in the conclusion.
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Unstructured Mesh Generation
Rozehnalová, Petra ; Roupec, Jan (referee) ; Hlavička, Rudolf (advisor)
Meshes based on triangulation (2D) or tetrahedralization (3D) are widely used in applications such as computer graphics, interpolation, surveying, and terrain modelling. Although the most important use is in numerical methods for the solution of partial differential equations. This solution is use for simulation of complex physical processes, which are described by this equations. The main topic of this thesis is mash generation.
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System for digital short-range wireless communication
Rébl, Miroslav ; Kolka, Zdeněk (referee) ; Tošovský, Petr (advisor)
This project includes the design of the System for digital short-range wireless communication. The methodology of the communication between net only one device type based system is proposed. The thesis describes system communication rules and used ways for protection of a correct transmission. Furthermore,the project descibes realizasion of the digital wireless communication with selected functions.
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Analysis of the stator and rotor pack termination effect on the synchronous machine by FEM
Michailidis, Petr ; Valenta, Jiří (referee) ; Skalka, Miroslav (advisor)
This thesis deals with simulation’s possibilities of the electromagnetic fields in electrical machines. A finite element method is the final element technique. The content of this thesis is a model and mesh creation and electromagnetic simulation of synchronous machine. The stator and rotor pack termination effect on the synchronous machine.is analyzed by finite element method in ANSYS program. The type of the stator termination pack is described by four segments. The magnetic field distribution is deformed due to the material properties of used segments. In the next part a methodics of mesh creation is shown. The mesh quality (in term of elements number and elements shape) is important due to the solution accuracy and speed.
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