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Computational modelling of noise inside cabin of aircraft VUT 100 Cobra
Prnka, Jiří ; Houfek, Lubomír (referee) ; Švancara, Pavel (advisor)
This master’s thesis deals with the computational simulation of low-frequency noise inside the cabin of small commercial airplane VUT 100 Cobra. For this low-frequncy range deterministic methods: Final Element Method (FEM) and Boundary Element Method (BEM) are used for simulation of the dynamic behaviour of the object. FEM has been used to compute eigenmodes and eigenfrequences of the structure of the aeroplane cabin and of the acoustic space inside cabin. Then response to harmonic excitation of engine represented by unit forces in place of contact has been computed. Obtained velocities on the surface of the cabin are then used as the basis for the noise calculation inside the cabin using BEM. After that effect of some construction modifications on sound level inside cabin are evaluated by computational modelling.
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Static and dynamic assessment of an outlook tower construction
Valíček, Jan ; Kala, Jiří (referee) ; Salajka, Vlastislav (advisor)
This thesis deals with static and dynamic analysis of an lookout tower construction. For dynamic analysis a computational model in ANSYS software is created. Static analysis is performed by Scia Engineer software. Both of this software use finite element method. It is also focused on wind load determination by Eurocode 1, structural factor calculation, modal analysis and vortex shedding. Verification of selected parts according to Eurocodes is included.
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Study of Power Plant Connection to Power Network
Sýkora, Martin ; Kurfűrst, Jiří (referee) ; Paar, Martin (advisor)
It is necessary to judge the influences of producers on the electric compounds while creating electrical energy or during the regulation of those existing. These analyses are sorted out by so called studies of connectivity. These calculations analyze the degree of connection of the producer and the standby unit during a break-down. The results of this report are several recommendations for creating such unit and succeeding steps leading to secure the stability and safety of the electric compound operation. The aim of this thesis is to discuss about software for PC solutions for static and dynamic network model, to draft power outlet into a network of generating high voltage, to complete a study of connectivity with respect to all the distortion factor, as increased voltage, inrush current at startup, flicker, harmonic currents, interference ripple, contribution to short-circuit current, reactive power control options, and demands for compensation.
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Remote measuring systems and its utilization in practise
Kukla, Zdeněk ; Škoda, Jan (referee) ; Baxant, Petr (advisor)
This master’s thesis is dealing with remote measuring systems and their utilization in power engineering. In the first part there are described requirements on an autonomous measuring system and description of AMM and AMR systems. Communicating and data flows working on accurately defined communicating layers are also depicted in this part. The attention is devoted to the possibility of data processing and functions of devices offered by these attributes. In the following part there are described reasons for utilization of remote measuring systems in power engineering and the main advantages of connection of more devices into one unit. After finding of required parametres and functions of systems, a suggestion of terminal device is created in the same way. The suggestion is described in the measuring part with A/D converter, processing in microprocessor, measuring and evaluating alogorithms and attributes of communication of bus used. The last part is devoted to utilization of remote analysis in small power stations in dispersed production. Formation of deformation of voltage, harmonic analysis of signal and its application for data processing are described there. Described analysis was tested on data acquired from a cogeneration unit.
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Modeling of thin-walled frames mechatronic systems with fillet welds and their influence on the natural frequency
Appel, Martin ; Hadaš, Zdeněk (referee) ; Vosynek, Petr (advisor)
This bachelor thesis is focused on methods of reduction degrees of freedom and their application in mechatronical system. Next part is focused on fillet welds and their modelling in Ansys Workbench software. Individual possibilities of geometry of welds are analysed by modal, static and harmonic analysis. Aim of this thesis is comparison of results of analysis for different methods of geometry of welds. Then it compare results of modal analysis in Ansys Workbench and Adams software. Finally the work deals with possibilities of exporting from Ansys Workbench to Adams, Matlab and Excel software.
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Porovnání usměrňovače s šířkově pulzní modulací s usměrňovačem fázově řízeným
Lettl, Jiří
The presented paper deals with measured waveforms of realized PWM rectifier with practically sinusoidal input current and controllable phase shift between input current first harmonic and supply voltage first harmonic. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.
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Kritický stav v tenkém Nb filmu
Youssef, A.E. ; Švindrych, Z. ; Hadač, J. ; Janů, Zdeněk
We present high resolution measurements of temperature dependence of low frequency ac magnetic susceptibility of superconducting Nb thin film in perpendicular time-varying periodic applied magnetic fields. We map this data, including harmonics, to the ac susceptibility calculated on basis of the complete analytical model of magnetization of thin superconducting disk in critical state. We find an excellent agreement between the measured and model data for temperatures up to 0.9997Tc
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Carpe diem – Raymond E.A.C. Paley: life and scientific work (1907-1933)
Zolotarev, Igor ; Žitný, K.
Raymond Edward Alan Christopher Paley, the student of G.H. Hardy and J.E. Littlewood, influenced the progress of harmonic analysis in the 20th century not only through the proper scientific publications about Fourier analysis in the complex domain, lacunary series, trigonometric interpolation and developments in polynomials, but by means of the collaboration with the co-authors J.E. Littlewood, A. Zygmund and N. Wiener, too.
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