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Experimental analysis of a fixed beam dynamic behavior
Poduška, Jan ; Houfek, Lubomír (referee) ; Březina, Lukáš (advisor)
This thesis is dealing with analysis of dynamic behavior of a fixed beam. An analysis of the applied mathematical model is proposed in the work. The mathematical model is then realized in MATLAB programming environment. Modal frequencies and mode shapes are con- sequently computed and results are compared to those obtained from the experimental modal analysis.
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Response of atypical vertical rotor of a water turbine to excitation by impeller imbalance and generator rotor imbalance
Sitte, David ; Houfek, Lubomír (referee) ; Fuis, Vladimír (advisor)
This master’s thesis deals with the dynamic behaviour of vertical Francis turbine, which is atypical its shaft length. In the first part of thesis, there is theoretic research of water turbine, which is followed by derivation of equations for the Stodola rotor. The second part deals with the creation of the turbine shaft in 1D and 3D. A modal analysis was performed in the ANSYS Workbench software, based on which the Campbell diagram is created and it was determined the critical speed. And the harmonic analysis from which was determined the forces response in radial bearings, amplitude of deviation in radial direction in the turbine impeller and the generator and the axial displacement located in turbine impeller and axial bearing. 1D and 3D solutions were compared between themselves.
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Models of Dynamics and Responses of Multi-body Systems
Kšica, Filip ; Houfek, Lubomír (referee) ; Hadaš, Zdeněk (advisor)
The aim of this diploma thesis is to evaluate the potential of available methods for simplification and reduction of complex models of technical systems and their integration with experimental models. Finding methods, which would allow us to create models and run simulations in shorter periods of time, is key in design process of modern technical systems. In the beginning of this thesis, a theory necessary for understanding and application of presented methods is given. These methods can be separated into two groups, first as experiment related, second as simulation related. The first group contains methods for experimental evaluation of response and its use for dynamic system identification. The second group contains methods of finite element model creation, with the usage of standard structural elements as well as Component Mode Synthesis substructures, and these models are in the following step reduced into state space models. In the next step, all presented methods are applied on simple experimental structure. In conclusion, the results of simulations are the subject for comparison not only from quantitative point of view, but also, for the purpose of practical application, in terms of time, feasibility, versatility and accuracy. The system identification method along with state space method proved to be very suitable. The results presented in this thesis might help, by selecting the appropriate method, in simpler evaluation of dynamic properties of technical structures.
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Analysis of uncertainties in the calculation of residual stresses
Dubravec, Kristián ; Houfek, Lubomír (referee) ; Návrat, Tomáš (advisor)
This thesis is about analysis of uncertainties in the calculation of residual stresses, which are homogeneous and measured by the hole-drilling method. Stochastic approach is explained using models of beams. Theory of residual stresses is included. Source code for evaluating residual stresses deterministically and stochastically is created using the Python language. Sensitivity analysis of input parameters is performed.
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Simulation modeling of parallel mechanisms
Cintula, Ladislav ; Houfek, Lubomír (referee) ; Březina, Lukáš (advisor)
Parallel mechanisms are characterized by their kinematic structure presented a closed kinematic chain. The end effector of mechanism is then bound to a base of over one arm. This design provides an advantage especially at high stiffness of mechanism and related properties. The disadvantage of such a structure is then usually very limited working space. In terms of simulation modeling is the construction due to its complexity rather problematic. The aim of work is design comprehensive simulation model chosen parallel mechanism and its analysis in selected working modes. Expected to use Adams simulation environment, if necessary. Matlab - SimMechanics and Ansys.
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Rotation Electric Actuator: parameter estimation and control
Palaj, Lukas ; Houfek, Lubomír (referee) ; Grepl, Robert (advisor)
The bachelor’s thesis deals with design of printed circuit board in the first part. The board will be used for connecting rotation electric actuator (REA) to the card MF624. It is written about electronic throttle and it’s particular parts, it’s connection to the card and estimation of parameters necessary for composing a virtual model in Simulink in the second part. After that control for the model is designed.
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Comparison of crack length measurement methods utilizing digital image correlation
Dziubek, Jan ; Houfek, Lubomír (referee) ; Ščerba, Bořek (advisor)
The thesis deals with the measurement of crack length using digital image correlation. The theoretical part of the thesis presents the method of digital image correlation, crack problems, and also introduces conventional methods for measuring crack length. There are currently no universal procedures in the field of crack length measurement using DIC. Different authors have only proposed different procedures to find the crack tip. Three different methods are used to determine the crack length using digital image correlation. Use of the edge detection method in the displacement field, the inflection point search method and the deformation threshold method. The aim of this work is to describe and compare these approaches.
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