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DYNAMIC ANALYSIS OF THE SOIL-FOUNDATION INTERACTION
Martinásek, Josef ; prof. Ing. Alois Materna, CSc., MBA (referee) ; Kanický,, Viktor (referee) ; Salajka, Vlastislav (advisor)
Thesis deals with problems of the soil-structure interaction. In the theoretical part is described the approach to mathematical modeling of structure-foundation-soil interaction. The subsoil models are further described in detail, including the models with piles (both static and dynamics models). In the next chapter there is described the dynamics theory of the systems with single or more degrees of freedom. There is also an analysis of propagation, reflection and refraction of mechanical one-dimensional waves (P-wave, S-wave) and spatial waves (P- wave, SV-wave, SH-wave) and waves in homogeneous half-space (R-wave L-wave). The numerical analysis is logically sorted from hand calculation of the parameter change influence on the modal characteristics to complex computational FEM model of the machine with a foundation on piles placed in the spatial block of soil. Numerical studies aim to determine the influence of the subsoil model on the modal characteristics and thus confirm the absolute necessity of the subsoil model in tasks of dynamics. The next goal is to determine the appropriate key parameters of the computational model: the size of finite element, suitable shape of subsoil model, suitable inclination of boundary condition and suitable boundary conditions. For creating of set of computational models was used language APDL in conjunction with ANSYS software interface. All used input files are listed in the Annex.
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Wave propagation in homogeneous line
Brázda, Daniel ; Steinbauer, Miloslav (referee) ; Friedl, Martin (advisor)
This work deals with the propagation of electromagnetic waves. In the theoretical section describes the propagation of waves in the open space and the line. The main objective of this work is to design a new layout laboratory exercises in which students measure the behavior of waves on a homogeneous line. The design include measuring the standing wave ratio (SWR) using the digital SWR meter, measure the voltage measured along the line and measuring the frequency dependence of the input impedance of the line.
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Wireless Communication in Mobile Robotics
Hricišin, Tomáš ; Burian, František (referee) ; Žalud, Luděk (advisor)
This work deals with the fundamental principles of wireless communications in mobile robotics. It introduces overview of the use of different frequency bands for wireless communications needs and control of mobile devices in Czech Republic. It also contains a brief overview of all applicable technologies and available modules that can be used for wireless communication. The theoretical part deals with some of the protocols that were used in the practical part of this work and the manner of wave propagation in buildings. The practical part consisted of a design of our own application to monitor and control the module Mikrotik Routerboard. With this application we have tested and compared two wireless cards of this module.
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The 2nd International Conference on Advanced Modelling of Wave Propagation in Solids
Kolman, Radek ; Berezovski, A. ; Kruisová, Alena
The proceeding of the 2nd International Conference on Advanced Modelling of Wave Propagation in Solids presents papers related to analytical, numerical and experimental studies of linear and non-linear waves in conventional, advanced and modern materials like metamaterials and auxetic materials, to strongly dispersive wave propagation in inhomogeneous solids and to waves in materials with microstructure, etc. The recent advances and properties of analytical and numerical approaches and strategies are also included. Theoretical, computational as well as experimental contributions on the wave propagation are related to the proceeding.
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DYNAMIC ANALYSIS OF THE SOIL-FOUNDATION INTERACTION
Martinásek, Josef ; prof. Ing. Alois Materna, CSc., MBA (referee) ; Kanický,, Viktor (referee) ; Salajka, Vlastislav (advisor)
Thesis deals with problems of the soil-structure interaction. In the theoretical part is described the approach to mathematical modeling of structure-foundation-soil interaction. The subsoil models are further described in detail, including the models with piles (both static and dynamics models). In the next chapter there is described the dynamics theory of the systems with single or more degrees of freedom. There is also an analysis of propagation, reflection and refraction of mechanical one-dimensional waves (P-wave, S-wave) and spatial waves (P- wave, SV-wave, SH-wave) and waves in homogeneous half-space (R-wave L-wave). The numerical analysis is logically sorted from hand calculation of the parameter change influence on the modal characteristics to complex computational FEM model of the machine with a foundation on piles placed in the spatial block of soil. Numerical studies aim to determine the influence of the subsoil model on the modal characteristics and thus confirm the absolute necessity of the subsoil model in tasks of dynamics. The next goal is to determine the appropriate key parameters of the computational model: the size of finite element, suitable shape of subsoil model, suitable inclination of boundary condition and suitable boundary conditions. For creating of set of computational models was used language APDL in conjunction with ANSYS software interface. All used input files are listed in the Annex.
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Finite element modeling of the signal propagation in a thin tube and comparison with experimental data
Kruisová, Alena ; Kolman, Radek ; Trnka, Jan ; Mračko, Michal
In finite element modeling of wave propagation problems, both the spatial and temporal discretization lead to dispersion errors. It means that the phase velocity of propagated wave is related to its frequency. In framework of temporal-spatial dispersion analysis, the time step size for implicit time integration method based on the Newmark method is proposed for linear and quadratic serendipity plane finite elements. In this paper, we verify the theoretical dispersion analysis by elastic wave propagation in thin tube, where experimental results are known. Such time step size was used in finite element modeling of the stress wave propagating in this thin steel tube, the results of simulations were compared with experimental results.
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