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The modal damping ratio analysis of the mechanical part using the OMA method
Sodomka, Tomáš ; Lošák, Petr (referee) ; Houfek, Lubomír (advisor)
In one of the first hours of study at the Institute of Mechanics of Bodies, Mechatronics and Biomechanics, the author of this work received three basic recommendations regarding measurement: 1) Do not measure! 2) If you measure, do not repeat the measurement!! 3) If you repeat the measurement, do not compare the measurements!!! However, this thesis boldly violates all three recommendations. In the introductory theoretical part, it briefly introduces the vibration of multi-degree of freedom damped systems and describes experimental ways of determining the modal damping. It also summarizes the Operational Modal Analysis (OMA) approach, explains the principle of the FDD method, and introduces EFDD (Enhanced Frequency Domain Decomposition) method which allows to determine not only natural frequencies and shapes as FDD does, but also modal damping of the shapes. A script in Matlab environment for processing vibrations using EFDD method is one of the thesis outputs. The script is first tested by computational model, where a model system with known damping is tested and damping is determined by the script. Subsequently, the work moves to the actual measurement of the real system - a bonded bar which is analysed by Experimental Modal Analysis and OMA, while the second variant uses commercial EFDD method (Brüel a Kjr company) and programmed script. In the conclusion of the thesis the damping results are compared to each other. The diploma thesis continues in Ing. M. Pop’s thesis – Modal Analysis Experimental Method Verification. From this work a part of measured data is taken. Specific cases of data use are always listed in the appropriate section of the text.
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Mechatronic drive systems
Pulec, Václav ; Houfek, Lubomír (referee) ; Kratochvíl, Ctirad (advisor)
The purpose of this bachelor's thesis is to describe terms like mechatronics, mechatronics approach and mechatronics product. The thesis systematically compares mechatronic and conventional drive systems and defines their specific differences. It introduces several innovation examples which were created thanks to mechatronics.
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Testing platform with 3 dof
Spáčil, Tomáš ; Houfek, Lubomír (referee) ; Grepl, Robert (advisor)
This thesis deals with development and construction of parallel manipulator with three degrees of freedom whose assumption of usage is testing tanks for NH3. In this work we are going to investigate the design of the mechanism in Matlab Simulink. Design of the electronic is introduced and also the control program is developed. The result of the work will be a prototype of manipulator.
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Dynamic analysis of oscillations with multiple degrees of freedom
Schulmeister, Jiří ; Houfek, Lubomír (referee) ; Březina, Lukáš (advisor)
This thesis is dealing with analysis of oscillating with multiple degrees of freedom and with example of dynamic behavior of system with two degrees of freedom with different input signals for purposes of dynamic lessons. Conventional method of making equations of motion by Lagrange’s method and their consecutive analysis is inscribed in the work. As example of system with two degrees of freedom is chosen quarter car model. Responses to different input signals are shown for the model. It is made in MATLAB/SIMULINK.
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Design and implementation of education model "Oscilator 1 dof"
Deďo, Michal ; Houfek, Lubomír (referee) ; Grepl, Robert (advisor)
The purpose of bachelor’s thesis is the design, implementation and testing of the educational model oscillator with one degree of freedom ", which should provide students with the possibility of closer assimilation of events generated by the oscillation, as well as to familiarize the student with the control model through Real Time Toolbox and evaluating the results of measurement. Work should provide students with real-time overview of these problems, which, in the future may bring to light the causes, or even prevention of disorders caused by oscillation.
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Three dimensional force sensor
Černý, Hynek ; Krejčí, Petr (referee) ; Houfek, Lubomír (advisor)
The bachelor’s thesis dealt with the design of a force sensor, which was supposed to do measurements of forces in three axes independently. The another required output of the work was creation of drawings. The design and optimalization of shape and dimensions of the sensor was made mainly in program called ANSYS. An important part of the work was the expression of final relations for the calculation of forces both analytically using simple elastic strength and the numerical finite element method. The last part of the work was an experimental measurement, which was supposed to verify accuracy of both methods for forces expression and also correct functionality of the sensor.
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Implementation of control software of device for measuring residual stresses by drilling method
Švehla, Lukáš ; Houfek, Lubomír (referee) ; Krejčí, Petr (advisor)
The diplom thesis deals with modernization of older drill out machine MTS3000 for measurement of residual stress. To make the device work it is necessary to keep running computer control card and necessary software. Because a producer does not provide any upgrade, it was decided to put the device into operation by creating new software. At first an analysis of drilling method and function of device MTS3000 - Restan was made. Next step was to disassemble and analyze the station of the drilling device. Then the station was put into operation and modified for control via USB device NI USB 6009. Finally a computer program in LabVIEW environment was created to automate the measurement process. Program has two main tasks: one is to control the drilling cycle of the machine. Another one is to acquire data from measuring amplifier station.
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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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Simulation of vehicle dynamics using V-REP software
Borek, Dušan ; Houfek, Lubomír (referee) ; Grepl, Robert (advisor)
This theasis deals with modeling dynamics and visualization of experimental vehicle CAR4 in software V-REP. The first part shows introduction with V-REP and its possibilities for usage in simulations. The second part presents modelling of CAR4 vehicle and its control by using software V-REP and Matlab. In last part are models of vehicle tested in simulation
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