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Digital Holographic Method for Piezoelectric Transformers Vibration Analysis
Psota, Pavel ; Kopecký, V. ; Lédl, Vít ; Doleček, Roman
The paper describes a holographic method for vibration analysis in nanometer range. The method was successfully applied on different types of piezoelectric transformers and the measurement results are introduced. To proof the reliability of the method it was done a comparing simultaneous measurement of a piezoelectric component by the holographic method and the well-established single-point interferometric method. Results showing the minimal deviation of both methods are presented in the final part of the paper.
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Measurement of Vibration Mode Structure for Adaptive Vibration Suppression System by Digital Holography
Psota, Pavel ; Lédl, Vít ; Doleček, Roman ; Mokrý, P. ; Kopecký, V.
Previously the frequency-shifted digital holographic interferometry (FSDHI) for measurement of vibration amplitudes in range of nanometers was introduced and verified by authors [1,2]. The method FSDHI addressed some of the drawbacks of the conventional methods and was used mainly for piezoelectric transformer vibration amplitudes and mode structures measurement [3]. The limiting factor for application of this method is the maximal measured value of the vibration amplitude without the risk of ambiguity. The value is approximately 80nm for the frequency doubled Nd: YAG line. Since FSDHI enables us to precisely measure vibration amplitudes over the whole inspected area with very high lateral resolution, it could also be a very useful tool for measurement of vibration amplitudes and mode structures for research in the field of adaptive suppression systems. Such a measurement would provide a necessary feedback about the system behavior.This was the reason why we put an effort
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Comparison of holographic setups used in heat and mass transfer measurement
Doleček, Roman ; Psota, Pavel ; Lédl, Vít ; Vít, Tomáš ; Kopecký, V.
The authors of the paper deal with measurement of heat and mass transfer for several years and they have frequently used few techniqes for measurement of refractive index distribution based on holographic interferometry. Some of the well known techniques have been modified some and some new ones developped. Every technique could be applied with success in different type of meassurement and obviously every one has set of properties making them unique. We decided to digest few different basic techniques and describe its properties in this paper with the aim to help the reader select the proper one for their measurement. The list of techniques and its properties is not comprehensive but schould serve as a basic orientation in the field.
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Měření piezoelektrického aktuátoru pro posun textilií metodou digitální holografie s frekvenčně posunutou referenční vlnou
Lédl, Vít ; Václavík, J. ; Rusín, L. ; Erhart, J. ; Kopecký, V.
The actuator for moving the fabric is under development. It is necessary to characterize its properties. Time average holographic interferometry seems to be suitable tool for this purpose. However it is impossible with standard technique to resolve amplitudes in tens of microns, which are characteristic for the operation of the actuator. Time average holographic interferometry with frequency shifted reference wave has to be applied to solve this problem. Few expositions of the vibrating actuator have been captured with different frequency shift of the reference wave. Bessel functions obtained from these interferograms were fitted together by the automated software. The shape and the amplitude of the movement were successfully measured in whole area of actuator.
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