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Processing of electromagnetic and acoustic emission signals during mechanical stressing of solids
Šopík, Martin ; Holcman, Vladimír (referee) ; Koktavý, Pavel (advisor)
Electromagnetic emission and acoustic emission are physical phenomena evoked in non-conductive material by the sudden release of energy that generate rising cracks in material structure. The significant is a fact that these emission signals are detected already in stadium of materials loading whereof can be used e.g. at non-destructive diagnostics of building materials and constructions. In the appropriate manner processing of the emitted signals then make possible to obtain valuable informations for study physical properties of cracks. Master’s thesis describes methods designed for important signal data ascertainment in time, frequency even time-frequency domain. It can be e.g. start time, maximum value, dominant frequency in spectrum etc. All these methods are implemented into main program. Next load is formularization of source signal transformation which is given by used measuring circuit. Analytical method is chosen for solving. It means finding out reserve electrical circuit with constant element values. Resultant circuit approaches original circuit with less square error than existing way. The signal transformation is described by differential equation of second order with constant coefficients. MATLAB software is used for all computations and projections.
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Power amplifier for 2 metres radio amateur transmitter
Klapil, Filip ; Vařacha, František (referee) ; Prokeš, Aleš (advisor)
This work deal with development a solution of a power amplifier for 2 metres radio amateur transmitter with a minimum output of 1 kW. Part of the solution is to use a commercial module of power amplifier. In addition, the design of the input attenuator, the switching elements in the signal path, the output filter and the protection circuits including cooling. The bachelor thesis contains a proposal of a system solution with a discussion of required performance and legislative requirements. This is followed by a hardware section, where the work is devoted to the design of the hardware, the theoretical calculation of the components and the simulation. In the last part of the work deals with practical implementation, verification of function and measurement of achieved parameters and their evaluation.
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Application of electromagnetic and acoustic emission signals for localization of cracks generated during mechanical stressing of solids
Burděj, Václav ; Sadovský, Petr (referee) ; Koktavý, Pavel (advisor)
Terms of acoustic emission (AE) and electromagnetic emission (EME) designated physical effects and also as diagnostic methods based on these effects. These effects are caused by generated cracks in materials that rank among non-destructive techniques of material diagnostics. The advantage of them is that they do not affect the measured object and give us information about the current dynamic state of a tested material. One disadvantage of these effects is that they provide very low energy of signal emissions and make it difficult for broader usage. It is expected better localization of cracks in non-conductive materials by connecting of these two techniques (diagnostics). There are designed and described new methods for crack detection with usage of AE and EME signals in this work. Also there is description of measuring arrangement intended of crack detection and experimental sample for checking accuracy of methods for crack detection. There was performed comparison of accuracy of methods in crack detection.
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Power amplifier for 2 metres radio amateur transmitter
Klapil, Filip ; Vařacha, František (referee) ; Prokeš, Aleš (advisor)
This work deal with development a solution of a power amplifier for 2 metres radio amateur transmitter with a minimum output of 1 kW. Part of the solution is to use a commercial module of power amplifier. In addition, the design of the input attenuator, the switching elements in the signal path, the output filter and the protection circuits including cooling. The bachelor thesis contains a proposal of a system solution with a discussion of required performance and legislative requirements. This is followed by a hardware section, where the work is devoted to the design of the hardware, the theoretical calculation of the components and the simulation. In the last part of the work deals with practical implementation, verification of function and measurement of achieved parameters and their evaluation.
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Application of electromagnetic and acoustic emission signals for localization of cracks generated during mechanical stressing of solids
Burděj, Václav ; Sadovský, Petr (referee) ; Koktavý, Pavel (advisor)
Terms of acoustic emission (AE) and electromagnetic emission (EME) designated physical effects and also as diagnostic methods based on these effects. These effects are caused by generated cracks in materials that rank among non-destructive techniques of material diagnostics. The advantage of them is that they do not affect the measured object and give us information about the current dynamic state of a tested material. One disadvantage of these effects is that they provide very low energy of signal emissions and make it difficult for broader usage. It is expected better localization of cracks in non-conductive materials by connecting of these two techniques (diagnostics). There are designed and described new methods for crack detection with usage of AE and EME signals in this work. Also there is description of measuring arrangement intended of crack detection and experimental sample for checking accuracy of methods for crack detection. There was performed comparison of accuracy of methods in crack detection.
|
|
|
Processing of electromagnetic and acoustic emission signals during mechanical stressing of solids
Šopík, Martin ; Holcman, Vladimír (referee) ; Koktavý, Pavel (advisor)
Electromagnetic emission and acoustic emission are physical phenomena evoked in non-conductive material by the sudden release of energy that generate rising cracks in material structure. The significant is a fact that these emission signals are detected already in stadium of materials loading whereof can be used e.g. at non-destructive diagnostics of building materials and constructions. In the appropriate manner processing of the emitted signals then make possible to obtain valuable informations for study physical properties of cracks. Master’s thesis describes methods designed for important signal data ascertainment in time, frequency even time-frequency domain. It can be e.g. start time, maximum value, dominant frequency in spectrum etc. All these methods are implemented into main program. Next load is formularization of source signal transformation which is given by used measuring circuit. Analytical method is chosen for solving. It means finding out reserve electrical circuit with constant element values. Resultant circuit approaches original circuit with less square error than existing way. The signal transformation is described by differential equation of second order with constant coefficients. MATLAB software is used for all computations and projections.
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