Rotating blade vibration analysis using photogrammetry and tracking laser Doppler vibrometry

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dc.contributor.author Gwashavanhu, Benjamin
dc.contributor.author Oberholster, Abraham Johannes (Abrie)
dc.contributor.author Heyns, P.S. (Philippus Stephanus)
dc.date.accessioned 2016-08-08T05:48:33Z
dc.date.issued 2016-08
dc.description.abstract Online structural dynamic analysis of turbomachinery blades is conventionally done using contact techniques such as strain gauges for the collection of data. To transfer the captured data from the sensor to the data logging system, installation of telemetry systems is required. This is usually complicated, time consuming and may introduce electrical noise into the data. In addition, contact techniques are intrusive by definition and can introduce significant local mass loading. This affects the integrity of the captured measurements. Advances in technology now allow for the use of optical non-contact methods to analyse the dynamics of rotating structures. These include photogrammetry and tracking laser Doppler vibrometry (TLDV). Various investigations to establish the integrity of photogrammetry measurements for rotating structures involved a comparison to data captured using accelerometers. Discrepancies that were noticed were attributed to the intrusive nature of the contact measurement technique. As an extended investigation, the presented work focuses on the validation of photogrammetry applied to online turbomachinery blade measurements, using TLDV measurements. Through a frequency based characterization approach of the dynamics of the two scanning mirrors inside the scanning head of a scanning laser Doppler vibrometer (SLDV), TLDV is employed in developing a system that can be used to achieve a perfect circular scan with a Polytec SLDV, (PSV 300). Photogrammetry out-of-plane displacements of a laser dot focused on a specific point on a rotating blade are compared to displacements captured by the laser scanning system. It is shown that there is good correlation between the two measurement techniques when applied to rotating structures, both in the time and frequency domains. The presence of slight discrepancies between the two techniques after elimination of accelerometer based errors illustrated that the optical system noise floor of photogrammetry does contribute to inconsistences between photogrammetry and other measurement techniques. en_ZA
dc.description.department Mechanical and Aeronautical Engineering en_ZA
dc.description.embargo 2017-08-31
dc.description.librarian hb2016 en_ZA
dc.description.uri http://www.elsevier.com/locate/jnlabr/ymssp en_ZA
dc.identifier.citation Gwashavanhu, B, Oberholster, AJ & Heyns, PS 2016, 'Rotating blade vibration analysis using photogrammetry and tracking laser Doppler vibrometry', Mechanical Systems and Signal Processing, vol. 76-77, pp. 174-186. en_ZA
dc.identifier.issn 0888-3270 (print)
dc.identifier.issn 1096-1216 (online)
dc.identifier.other 10.1016/j.ymssp.2016.02.019
dc.identifier.uri http://hdl.handle.net/2263/56238
dc.language.iso en en_ZA
dc.publisher Elsevier en_ZA
dc.rights © 2016 Elsevier Ltd. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Mechanical Systems and Signal Processing. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Mechanical Systems and Signal Processing, vol. 76-77, pp. 174-186, 2016. doi : 10.1016/j.ymssp.2016.02.019. en_ZA
dc.subject Photogrammetry en_ZA
dc.subject Non-contact vibration analysis en_ZA
dc.subject Turbomachines en_ZA
dc.subject Tracking laser Doppler vibrometry (TLDV) en_ZA
dc.subject Scanning laser Doppler vibrometer (SLDV) en_ZA
dc.title Rotating blade vibration analysis using photogrammetry and tracking laser Doppler vibrometry en_ZA
dc.type Postprint Article en_ZA


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