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Final report on the MIT project no. CZ.01.1.02/0.0/0.0ú20_321/0023673
Zolotarev, Igor ; Pešek, Luděk ; Gabriel, Dušan ; Procházka, Pavel P.
The MIT project entitled Development of a switchgear for severe conditions and reduction of risks of critical infrastructure threat was focused on research, development of optimized design and provision of configuration technology for repeated production of different variants of modular system switchgear for use in severe conditions and reduction of risks of seismic threat, to ensure the reliability of critical infrastructure. The output is to be a prototype seismically robust device with a dynamically lightweight design, high reliability of switchgear and electrical equipment assembly function, and a software application for interactive design and documentation.
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Modal Analysis of the Flute
Vojtovič, Adam ; Votava, Tomáš (referee) ; Hájek, Petr (advisor)
The presented bachelor thesis deals with an influence of a fundamental shape and partial sections of flute on frequency of tones. A simple flute is designed and made according to the given formulas. The functionality of the flute is verified by measuring frequencies of each tone. These frequencies are compared with values given analytically and also with values of natural frequencies calculated by finite element method. General information about wind instruments is included in the thesis, too. Besides the clarification of fundamental principles of function of wind instruments, there are also derived fundamental formulas for calculation of natural frequencies of tubes.
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Determination of Cable Weakening using Dynamic Measurement
Bezručová, Kristína ; Nečas, Radim
Paper discusses the possibilities of measuring the dynamic response of cables to impulse excitation. Basic relations between cable force and natural frequency of cable and conditions of use on real structures are mentioned. Methods are applied on a pedestrian bridge in Napajedla. The aim of the measurement was to determine the cable force and to evaluate their condition and stress based on the dynamic response.
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Dynamic and heat transfer analysis of a container with measuring instruments for space probes
Zolotarev, Igor ; Bula, Vítězslav ; Šnábl, Pavel ; Gabriel, Dušan ; Dobiáš, Jiří ; Masák, Jan ; Snížek, Jan ; Souček, Jan
Rocket boosters and spacecraft are subject to intense acoustic environments during launch, which induce high levels of vibration in structural elements and equipment. In addition, elastic structural interactions with propulsion systems and flight control systems can produce low-frequency, high-deflection flight instabilities. Natural vibration of the container with measuring equipment were studied by numerical and experimental methods in the laboratory of Institute termomechanics CAS. Heat transfer analysis inside the container was made by FEM with respect to the conditions during start of the rocket and work in space.\n
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Analysis of the rotor packet prestress on the rotor critical speed
Lekeš, Filip ; Huzlík, Rostislav (referee) ; Lošák, Petr (advisor)
The presented diploma thesis deals with the modeling of the rotor packet in dynamic calculations and analysis of the influence of the packing pressing force on the critical speed of the electric motor. The thesis can be divided into three main parts. The first part discusses the current level of rotor packet modeling in dynamic calculations and also deals with analytical theories for subsequent experimental tests. The second part describes the implementation of two experiments to determine the equivalent modulus of elasticity. The first experiment is a four-point bending test and the second is an experimental modal analysis. The third part is used for comparing the results obtained from experimental tests and describes the calculation of the critical speed of the rotor package pressed on the shaft by the finite element method.
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Pressure and velocity pulsations of liquid in thin cylindrical domain
Oborná, Eliška ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The subject of this diploma thesis is a dynamic analysis of phenomena occurring in the thin cylindrical region, ie in a gab, which flows liquid by the given parameters. Through the simplifications introduced, it comes to the problem of structural and forced vibration for both the horizontal pulsation in a tube and the area of a compensating piston. The described method uses the separation of variables for pressure function. The speed function is derived from the already known pressure field distribution using the Navier-Stokes equation.
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Modal analysis of the swirl turbine runner
Valo, Lukáš ; Fic, Miloslav (referee) ; Čupr, Pavel (advisor)
The bachelor’s thesis deals with modal analysis of the swirl turbine runner. The main aim was to determine natural frequencies and mode shapes of the turbine runner. Both detailed and simplified models of geometry of the turbine runner were analysed for two types of boundary conditions. The ANSYS program was used to carry out numerical simulations. Experimental measurement was realised to verify and to compare results of calculations.
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Explanation of the sloshing motion in a tank, for a moving tank, for a fixed tank
Mrázek, Michal ; Habán, Vladimír (referee) ; Fialová, Simona (advisor)
This bachelor's thesis deals with mathematical model of sloshing in a tank. Laplace's equation is developed. Boundary conditions for a still rectangular container and for a container under sinusoidal translation are established. Expressions for the free surface elevation and natural frequencies in oscillating tank are determined. Baffles are suggested as a method to minimize the free surface elevation. In the final part, analytical model is compared with numerical solution with overall good agreement.
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