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Dynamic Characteristics of Exhaust System and Noise Transmition to the Car Cocpit
Novotný, Václav ; Ramík, Pavel (referee) ; Svída, David (advisor)
This thesis deals with the complex analysis of dynamic characteristics of the exhaust system and the transmission of noise from exhaust system to the vehicle. In the first part is performed modal analysis, which is compared to experimentally measured data. Modal analysis of the complete exhaust system is made with focusing on the influence of temperature of the exhaust system. There is also performed an analysis of noise transmission from exhaust system to the car cockpit.
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Pedestrian bridge across the lagoon
Bezručová, Kristína ; Kaláb,, Pavel (referee) ; Nečas, Radim (advisor)
The aim of this thesis is the design and analysis of pedestrian bridge across the lagoon. Three variants were designed. The variant of structure, which combines stress ribbon with steel arches, was chosen for analysis. There is a chapter in this thesis which deals with an ideal shape of arches for different types of loads. The calculation of load effects was made in software Ansys 17.0, considering scnstruction stages. Ultimate limit state and state limit state are evaluated. For evaluation of concrete cross sections was used MS Excel. Steel cross sections were evaluated in software Ansys 17.0. d Dynamic behaviour of construction was assessed. The mode shapes and natural frequencies were calculated. The harmonic excitation response was studied. The loss of stability was checked. The design and assessment are according to the european standards.
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Simulation of Noise Emitted by a Single-stage Gearbox
Motl, Daniel ; Hadaš, Zdeněk (referee) ; Lošák, Petr (advisor)
The level of noise and vibration of gearboxes is one of the most important parameters for today´s customers. This thesis deals with mathematical acoustic behavior modelling and its contribution to the gearbox design using finite element method. The process is presented at three computations models. Two of those were validated with experimental measurement. Acoustic analysis were performed with software FFT ACTRAN.
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Comparison of modal properties of steam turbine impeller with blades of different lengths
Havlásek, Michal ; Chromek, Lukáš (referee) ; Lošák, Petr (advisor)
The presented master's thesis deals with the safety assessment of several variants of the impeller with different blades length. The motivation for creating this thesis is to find the solution of the problem situation which is characterized by the breakdown of the steam turbine impeller with blades length of 30mm. As confirmed in this thesis, the impeller with blades length of 30mm is operated in the resonance. Likewise, according to the technical standard ČSN EN ISO 10437 its operation is not safe. As the correction action for the problem situation solving is proposed the prolongation of the impeller's blades. The safety is detected for six variants of impeller with dierent blades length. For each variant, there is executed a modal analysis and its results are drawn up into the Campbell diagram. On the basis of this diagram, the safety of individual components is evaluated. The last part of the masters thesis concerns with the examination of the influence of blades length on the modal properties of the impeller.
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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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Zeroshifting Transmission Mechanism Design
Mičola, Ivo ; Prokop, Aleš (referee) ; Svída, David (advisor)
This thesis deals with no delay gear shifting. The first part is devoted to theoretical introduction. The next part describes comprehensive approach to vehicle dynamics, the choice of gear ratios, the use of reverse engineering to model the interior of the gear housing and the actual structural design of the internal components and strength analysis. Moreover, this work should fill the gap in the available literature which is publicly accessible.
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