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High-Frequency Pulsations Modeling
Střecha, Ludvík ; Kubálek, Jiří (referee) ; Habán, Vladimír (advisor)
The diploma thesis deals with the mathematical modeling of high-frequency pressure pulsations in water turbines. Pulsations are caused by the interaction between stator a rotor blades. These high-frequency pressure pulsations then cause high cycle fatigue of the head cover, spiral casing, runner and distributor. The mathematical model is solved by transfer matrix method. Data are processed in F-A char and MS Excel programs. Final results are demonstrated by frequency amplitude characteristics and by pressure mode shapes, where comparison of the mathematical model with the measurement is shown.
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Effect of the environment on the dynamic properties of simple parts
Nováková, Soňa ; Himr, Daniel (referee) ; Habán, Vladimír (advisor)
The dynamic characteristics of the object are influenced by the changes of the envi-ronment. The objective of this report is to examine how the changes of the environment influ-ence the dynamic characteristics of the object. The main aim is to compare the natural fre-quencies of the object when suspended and then actuated when being surrounded by air and submerged in water. The object in question is a cylindrical pipe, which was gradually short-ened during the experiment. These changes in size also affected the natural frequencies and the mode shape, which is discussed as well. The results of the experimental modal analysis are compared to calculations run in ANSYS software.
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Printed Circuit Board Modal Analysis Results Comparison from Experimental and Computational Modeling
Oplt, Tomáš ; Vosynek, Petr (referee) ; Tošovský, Jiří (advisor)
Modal analysis of printed circuit board results, gained from computional and experimental modeling, have been compared. Anylyses have been performed on dummy boards (models without electronic components), created as one-layered at first, then as three-layered PCB. Board is usually clamped by its longer edges with wedgelock. In order to enable the realization of boundary conditions in computional and experimental modeling, real clamping has been simplified to simply supported. Computional models have used FEM elements, which are comomnly used in this type of problem. Determined results have been evaluated by comparing the experimental modeling results. Models‘ sensitivity on modification of element length and number of elements through thickness have been performed.
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Effect of the environment on the dynamic properties of simple parts
Nováková, Soňa ; Himr, Daniel (referee) ; Habán, Vladimír (advisor)
The dynamic characteristics of the object are influenced by the changes of the envi-ronment. The objective of this report is to examine how the changes of the environment influ-ence the dynamic characteristics of the object. The main aim is to compare the natural fre-quencies of the object when suspended and then actuated when being surrounded by air and submerged in water. The object in question is a cylindrical pipe, which was gradually short-ened during the experiment. These changes in size also affected the natural frequencies and the mode shape, which is discussed as well. The results of the experimental modal analysis are compared to calculations run in ANSYS software.
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|
|
Printed Circuit Board Modal Analysis Results Comparison from Experimental and Computational Modeling
Oplt, Tomáš ; Vosynek, Petr (referee) ; Tošovský, Jiří (advisor)
Modal analysis of printed circuit board results, gained from computional and experimental modeling, have been compared. Anylyses have been performed on dummy boards (models without electronic components), created as one-layered at first, then as three-layered PCB. Board is usually clamped by its longer edges with wedgelock. In order to enable the realization of boundary conditions in computional and experimental modeling, real clamping has been simplified to simply supported. Computional models have used FEM elements, which are comomnly used in this type of problem. Determined results have been evaluated by comparing the experimental modeling results. Models‘ sensitivity on modification of element length and number of elements through thickness have been performed.
|
|
| |
|
|
High-Frequency Pulsations Modeling
Střecha, Ludvík ; Kubálek, Jiří (referee) ; Habán, Vladimír (advisor)
The diploma thesis deals with the mathematical modeling of high-frequency pressure pulsations in water turbines. Pulsations are caused by the interaction between stator a rotor blades. These high-frequency pressure pulsations then cause high cycle fatigue of the head cover, spiral casing, runner and distributor. The mathematical model is solved by transfer matrix method. Data are processed in F-A char and MS Excel programs. Final results are demonstrated by frequency amplitude characteristics and by pressure mode shapes, where comparison of the mathematical model with the measurement is shown.
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