National Repository of Grey Literature 24 records found  beginprevious15 - 24  jump to record: Search took 0.01 seconds. 
Modal analysis of a container with measuring equipment for space mission
Zolotarev, Igor ; Bula, Vítězslav
This paper continues investigations of some measuring equipment for space mission. The frequency-modal properties a container with several slots and measured desks are studied. The natural frequencies and corresponded modes obtained using measuring methods are presented for several combinations of the container components.
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
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.
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.
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.
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.
Assesment of assembling inaccuracy on the coil spring lifetime
Stavárek, Václav ; Hadaš, Zdeněk (referee) ; Lošák, Petr (advisor)
This bachelors thesis is focused on helical compression springs with rectangular wire cross-section. In cooperation with an unnamed company it examines few possible causes of their failure rate. This thesis also includes experimental measurement of change of the spring stiffness after it underwent a high number of cycles.
Creation of database of stator core stiffness of rotational electrical machines
Podzemný, Zdeněk ; Donát, Martin (referee) ; Dušek, Daniel (advisor)
In this thesis is wrote up a complete procedure of stator core stiffness determination using finite element method (FEM), subsequently, the stator core stiffness database was created according to this procedure. In the next chapter is carried out a sensitivity analysis of one chosen stator core, which led to identifying parameters that affected its stiffness the most. Finally, a modal analysis of one synchronous machine was performed using FEM, in order to determine the effect of stator core stiffness on modal characteristics of the machine. Several modal shapes and corresponding natural frequencies were computed in this analysis, then only a few shapes with the highest core effect were chosen and compared.

National Repository of Grey Literature : 24 records found   beginprevious15 - 24  jump to record:
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