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Experimental determination of the liquid influence on an oscillating body
Grešáková, Kristýna ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
Damping and natural frequency of a vibrating body or a system is not easy to estimate during the design phase of~project. If the body is submerged in water, estimating becomes even more complicated. This~work focuses on experimental determination of the liquid influence on an oscillating body. The~presented modal analysis was executed on two bodies when being surrounded by air, but~also when gradually and fully submerged in water using two reservoirs with different dimensions. The collected data was analyzed with a suggested hybrid method, which determined the damping ratio and the natural frequency. Added mass was calculated employing the Ansys software. Part of the presented work focuses on the selection of a suitable time window for the Fourier transform.
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Design of mobile stand for suspending of electrodynamic exciter for aeroelastic phenomena testing in aviation
Vojáček, Jan ; Löffelmann, František (referee) ; Navrátil, Jan (advisor)
This Bachelor thesis deals with the design of mobile stand for carrying out ground vibration tests in aviation applications. These tests mainly judge the tolerance of aircraft against flutter. The start of the thesis deals with the teoretical background of aeroelasticity together with the historical events that led to the origins of research of such phenomenons. The second part of the tesis clarifies the motivation for designing the stand through overview of simmilar equipment avaiable on the market and through introducing the equipment used at the aircraft testing laboratory at the Institute of Aerospace Engineering. Third part of the thesis states possible approaches to the overal design of the stand and then crosses over to the chapter that discusses the chosen solution of the design. At the end there are introduced the results of modal analysis. These results state the natural frequencies occuring in the range of frequencies that normally occur while testing.
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Analysis of the structure for the effects of earthquakes
Švejcar, Martin ; Martinásek, Josef (referee) ; Vlk, Zbyněk (advisor)
This master thesis deals with analysis of a selected construction subjected to a seismic load. In the Dlubal RFEM programme, a basic model was created and analyzed with the spectral analysis using response spectra and with the time analysis using accelerograms from the database of the programme. The outcomes from these analyses were compared. Subsequently, the same calculations were performed on modified models and the results of the internal forces and deformations of the structure were compared with the outputs obtained on the original basic model.
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Ball screw testing
Kukliš, Richard ; Jaroš, Aleš (referee) ; Fiala, Zdeněk (advisor)
The main goal was to design a test rig and create a methodology for evaluating the measured data from the life tests of linear motion systems with ball screws. The first part is the research of basic knowledge about ball screws, which are important for understanding the behavior of the entire ball screw motion system and methods created from previous experiments on similar issues. The next part of the thesis is directed at the design and selection of individual parts and sensors for the testing rig. The methodology is based on the evaluation of measured parameters describing the condition of the tested ball screw and it includes verification of the functionality of the test rig from the first measured data.
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Rubber damper of a four-cylinder diesel engine
Bauza, Erik ; Novotný, Pavel (referee) ; Píštěk, Václav (advisor)
A content of this diploma thesis is construction design of torsional vibration rubber damper of four-stroke diesel supercharged engine. It` s realized evaluation of crankshaft from aspect of torsional vibrations and checked mechanical stress of crankshaft without using rubber damper. Consequently basic parameters of rubber damper are specified, then checked mechanical stress of crankshaft and designed own construction design of damper.
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Modal analysis experimental method verification
Pop, Miroslav ; Lošák, Petr (referee) ; Houfek, Martin (advisor)
This diploma thesis deals with the issue of operational modal analysis, which is one of the newer areas of structural dynamics that makes it possible to estimate modal properties of structures directly during their operation. The aim of this work is to create theoretical basis of operational modal analysis, more specifically of Frequeny Domain Decomposition method. Furthermore, apply this method to a selected structure and verify the achieved results using computational modelling and experimental modal analysis. The technique of dividing the experiment to separate measurements using reference sensor was used. Evaluation of the operational modal analysis was performed using self-created function for the MATLAB software and using the commercial PULSE Operational Modal Analysis software. Obtained results were verified by computational modelling and experimental modal analysis.
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Design of a one-span slab bridge
Sobková, Sára ; Tomečka, Petr (referee) ; Nečas, Radim (advisor)
Subject of bachelor thesis is reconstruction of railway bridge on the route from Český Těšín to Ostrava-Svinov in km 6,482. The structure is located in the extraregion. There are two rail routes on the bridge and local road under the bridge. One-span slab reinforced consrete bridge is designed and placed on the rail as a replacement for bearings. the length of the bridge is 6 m. The sffects ot the load are calculated in the programe AxisVM and static calculation are made in the program Mathcad. Bending and shear steel is designed. Serviceability limit state is verified. Also the resistance of steel concrete to cyclic loading is calculated. Steel of the abuntment is designed to reduce the appearence of cracks above the working joint due to ahrinkage. Dynamic coefficient is verified.
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Modal Properties of 6-cylinder Tractor Engine Powertrain
Poláček, Milan ; Píštěk, Václav (referee) ; Dundálek, Radim (advisor)
Tato diplomová práce uvádí dynamiku klikového mechanismu šestiválcového řadového motoru za účelem návrhu klikového hřídele v CAD programu Pro/Engineer. Následuje popis vibrací klikového mechanismu a analytický výpočet jeho torzních vibrací. Hlavní část diplomové práce se pak zabývá konverzí hřídele do konečno-prvkového modelu v programu ANSYS a jeho importem do prostředí Adams/Engine. V tom je provedena modální analýza klikového ústrojí pro získání vlastních frekvencí a tvarů. Na konec práce je porovnán výstup z analytického řešení a výsledky z multi-body systému.
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Strength analysis of cutting tools
Petrlíková, Helena ; Madaj, Martin (referee) ; Zouhar, Jan (advisor)
This work is focused on the stress-strain analysis of a cutting tool. At the beginning, the study of available literature and scientific articles relating the topic is carried out. The solution of stresses and strains in whole real system has been carried out based on the computational simulation using the finite element method (FEM). The work contains a detailed description of the creation of the computational model. Model of geometry of the system has been created in the SolidWorks program. Computational simulation including the solution was implemented in the ANSYS Workbench program as well as in the classical environment of ANSYS 12.0. This work includes the presentation of results and subsequent stress-strain analysis of the cutting tool. Last part of this work deals with the modal analysis and harmonic analysis of cutting tools made in classical environment of ANSYS program.
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Steel Structure of Observation Tower
Virág, Patrik ; Pilgr, Milan (referee) ; Hron, Lukáš (advisor)
The subject of the diploma thesis is design and structural analysis of loadbearing steel structure of observation tower, which is located southeast of Černá Hora, township Blansko. The design is processed in two options. Parts of the thesis are engineering report, structural design report for both of the options and graphical documentation in specified range. The structure’s height is 25.3 m and maximal ground plan dimension is 6 x 6 m. Steel grade S355 was chosen as main material. The sub-objectives of the structural analysis are load effects calculations (permanent load, imposed load and climatic load), entering of loads to the calculation model and calculation of internal forces and deformations. An assessment of the supporting elements and selected joints is also included. There are dynamic design features considered in the calculation. All calculations were performed in accordance with valid ČSN EN standards.
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