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Analysis of dynamic parameters of laser vibrometers
Pavloň, Martin ; Vágner, Martin (referee) ; Havránek, Zdeněk (advisor)
This diploma thesis deals with the theoretical description of interference methods used to measure vibrations, examines main parasitic effects and analyses its contribution to achievable the resolution. In the practical part, it uses several measurements to verify the effects of the level of reflected beam, stand-off distance and speckle noise. It also proposes a practical experiment for measuring dynamic parameters and signal-noise ratio. Results show that, the noise is exponentially dependent on the level of the reflected beam. The visible maximum of the vibrometer proved to be critical in terms of time stability of the measured signal level in two of the three measurements. Results of the dynamic measurement show that, the measured deviations were not degraded or significantly disturbed by the noise signal. From the measurement of the speckle noise, it emerged that the lowest level of noise is achieved with smooth and highly reflective materials.
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Laser vibrometer with 2D scanning system
Rajm, Martin ; Klusáček, Stanislav (referee) ; Havránek, Zdeněk (advisor)
This thesis deals in the theoretical part with the non-contact vibration measurement by single point Laser Doppler vibrometer and it concretes constructions used in practice. It deals also with the possibilities of the laser beam scanning to measure the vibrations in the plane and there are also listed suitable-commercial systems for this solution. Mentioned sweep is immediately necessary for 2D scanning vibrometer construction. In the practical part, the single-point laser vibrometer OFV-5000 was expanded by scanning galvo system, supplemented by a measuring cards for signal acquisition from the vibrometer and suitable control hardware was chosen for mentioned laser. For the resulting hardware assembly was designed and implemented in LabVIEW measurement software, to control the 2D scanning system, to set the position of the laser beam and to process and to visualize of measured vibration signals in the plane. The functionality of the developed measuring system was checked by performed measurement and visualization of the velocity vibration of restraint girder, excited by shaker.
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Vibration mode shape extraction of bladed disk
Mekhalfia, Mohammed Lamine ; Procházka, Pavel ; Tchawou Tchuisseu, Eder Batista ; Maturkanič, Dušan ; Hodboď, Robert
This research paper deals with the experimental protocol followed to visualize the vibration mode shape of an aero-engine bladed disk. This study is based on a comparison between the numerical results obtained through Finite element methods (FEM) using ANSYS software and experimentally using the laser Doppler vibrometer. Therefore the bladed disk was transformed into a 3D virtual environment and structural analysis was performed. The results demonstrate a match between the numerical and the experimental one, this match offers the possibility for using the model for future studies.
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Analysis of dynamic parameters of laser vibrometers
Pavloň, Martin ; Vágner, Martin (referee) ; Havránek, Zdeněk (advisor)
This diploma thesis deals with the theoretical description of interference methods used to measure vibrations, examines main parasitic effects and analyses its contribution to achievable the resolution. In the practical part, it uses several measurements to verify the effects of the level of reflected beam, stand-off distance and speckle noise. It also proposes a practical experiment for measuring dynamic parameters and signal-noise ratio. Results show that, the noise is exponentially dependent on the level of the reflected beam. The visible maximum of the vibrometer proved to be critical in terms of time stability of the measured signal level in two of the three measurements. Results of the dynamic measurement show that, the measured deviations were not degraded or significantly disturbed by the noise signal. From the measurement of the speckle noise, it emerged that the lowest level of noise is achieved with smooth and highly reflective materials.
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|
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Laser vibrometer with 2D scanning system
Rajm, Martin ; Klusáček, Stanislav (referee) ; Havránek, Zdeněk (advisor)
This thesis deals in the theoretical part with the non-contact vibration measurement by single point Laser Doppler vibrometer and it concretes constructions used in practice. It deals also with the possibilities of the laser beam scanning to measure the vibrations in the plane and there are also listed suitable-commercial systems for this solution. Mentioned sweep is immediately necessary for 2D scanning vibrometer construction. In the practical part, the single-point laser vibrometer OFV-5000 was expanded by scanning galvo system, supplemented by a measuring cards for signal acquisition from the vibrometer and suitable control hardware was chosen for mentioned laser. For the resulting hardware assembly was designed and implemented in LabVIEW measurement software, to control the 2D scanning system, to set the position of the laser beam and to process and to visualize of measured vibration signals in the plane. The functionality of the developed measuring system was checked by performed measurement and visualization of the velocity vibration of restraint girder, excited by shaker.
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