Operational deflection shape of rotating object using tracking laser Doppler vibrometer

Khalil, Hossam; Kim, Dongkyu; Nam, Joonsik; Park, Kyihwan

doi:10.1109/icecs.2015.7440411

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…To estimate modal parameters of a rotating structure, encoders were used to track its angular position [18,19]. Khalil et al [18] proposed a method to track a rotating structure and measure its ODSs by attaching an encoder to it.…”

Section: Introductionmentioning

confidence: 99%

“…Khalil et al [18] proposed a method to track a rotating structure and measure its ODSs by attaching an encoder to it. Allen et al [19] developed an EMA method to measure mode shapes of a rotating fan with an encoder attached to its shaft to track its angular position. However, it is difficult to attach an encoder to a rotating structure such as a large horizontal-axis wind turbine; a more convenient OMA method and CSLDV system for tracking the angular position of a rotating structure and estimating its modal parameters and ODSs are needed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Operational Modal Analysis of Rotating Structures Under Ambient Excitation Using Tracking Continuously Scanning Laser Doppler Vibrometry

Lyu

Zhu

2021

Rotating Machinery, Optical Methods &Amp; Scanning LDV Methods, Volume 6

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A continuously scanning laser Doppler vibrometer (CSLDV) system is capable of rapidly obtaining spatially dense vibration measurement by continuously sweeping its laser spot along a path on a structure surface. This paper presents a new operational modal analysis (OMA) method for a rotating structure based on a rigorous rotating beam vibration theory, an image processing method, and a data processing method called the lifting method. A novel tracking CSLDV (TCSLDV) system was developed in this work to track and scan a rotating structure, and the real-time position of the rotating structure can be determined by image processing so that the TCSLDV system is capable of tracking a time-varying scan path on the rotating structure. The lifting method can transform raw TCSLDV measurement into measurements at multiple virtual measurement points as if they were measured by transducers attached to these measurement points. Modal parameters of the rotating structure with a constant speed, including damped natural frequencies, undamped mode shapes, and modal damping ratios, and operating deflection shapes (ODSs) of the structure with a constant or prescribed time-varying rotation speed can be determined by calculating and analyzing correlation functions with non-negative time delays among measurements at virtual measurement points. Experimental investigation is conducted using the TCSLDV system to study the OMA method with which modal parameters and an ODS of a rotating fan blade with different constant speeds, as well as an ODS of the rotating fan blade with a non-constant speed, are successfully estimated.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%