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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.
Na pracovišti TUL je vyvíjen aktuátor pro po posun textilií. Při vývoji je nezbytné charakterizovat jeho vlastnosti pro čež se zdá být užitečná metoda časově průměrované digitální holografie. Ovšem s touto metodou je nemožné přímo měřit amplitudy kmitů s amplitudou desítek mikrometrů, které jsou charakteristické pro vyvíjený aktuátor. Místo ní musí být použita metoda časově průměrované digitální holografie s frekvenčně posunutou referenční vlnou. Bylo zaznamenáno několik interferogramů aktuátoru s rozdílnými posuny referenční vlny. Ze zaznamenaných intenzitních průběhů, odpovídající Besselovým funkcím, byly pomocí softwaru rekonstruovány amplitudy kmitů v celé ploše aktuátoru.
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