Continuous Scanning Laser Vibrometry: A raison d’être and applications to vibration measurements

Maio, Dario Di; Castellini, Paolo; Martarelli, Milena; Rothberg, Steve; Allen, Matthew S.; Zhu, Weidong; Ewins, D. J.

doi:10.1016/j.ymssp.2020.107573

Cited by 43 publications

(8 citation statements)

References 90 publications

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“…Its classical point-scanning operation is convenient to study stationary or phase-referenced excitations, but many real-world cases and procedures such as impact testing involve non-stationary vibration fields. LDV has thus notably evolved since its invention to tackle these specific issues 54 , from multi-point approaches 55 to continuous scanning LDV 56 . Introduced in the 1990s, the continuous scanning technique modified the traditional paradigm of LDV, in which the number of measurement points defines the spatial resolution of the measurement map.…”

Section: Basic Principles Of the Measurement Techniquesmentioning

confidence: 99%

Comparison of three full-field optical measurement techniques applied to vibration analysis

O'Donoughue

Gautier

Meteyer

et al. 2023

Sci Rep

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Digital image correlation, deflectometry and digital holography are some of the full-field optical measurement techniques that have matured in recent years. Their use in vibroacoustic applications is gaining attention and there is a need for cataloging their performance in order to provide, to a broad community of users and potential future users, quantitative and qualitative evaluations of these three approaches. This paper presents an experimental comparison of the three optical methods in the context of vibration measurements, along with classical reference measurements provided by an accelerometer and a laser Doppler vibrometer. The study is carried out on two mechanical structures exhibiting various vibration responses when submitted to an impact.

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Section: Basic Principles Of the Measurement Techniquesmentioning

confidence: 99%

Comparison of three full-field optical measurement techniques applied to vibration analysis

O'Donoughue

Gautier

Meteyer

et al. 2023

Sci Rep

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show abstract

“…However, it requires long-time acquisition at each point, which is timeconsuming. A CSLDV continuously scans the vibrating surface, but it requires multiple reciprocating or cyclical scans for modal analysis [19][20][21][22][23]. In addition, SLDV and CSLDV need cyclical excitation, and thus the mode would not change during measurement.…”

Section: Introductionmentioning

confidence: 99%

Removing speckle noise from the signals of a laser Doppler vibrometer on moving platforms (LDVom) by ensemble empirical mode decomposition

Yang

Dollevoet²,

Li³

2022

Meas. Sci. Technol.

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With increasing requirements for structural stability and durability, effective monitoring strategies for existing and potential damage are necessary. A laser Doppler vibrometer on moving platforms (LDVom) can remotely capture large-scale structural vibrations, but speckle noise, a significant signal issue mainly when {one-way continuously} scanning from moving platforms, restricts its applications. A novel approach based on ensemble empirical mode decomposition (EEMD) is proposed to eliminate speckle noise. Moving root-mean-square (MRMS) thresholds are used to cut off signal drop-outs. With both numerically simulated and experimentally acquired signals, the proposed EEMD-based approach reveals the true vibrations despite the low initial signal-to-noise ratio (SNR). Other methods fail to eliminate the speckle noise. In physical experiments, the despeckled signal energy is concentrated at defect locations in the Hilbert-Huang spectrum. The identified damage locations agree well with the actual damage locations. Therefore, the developed approach demonstrates advantages and robustness of eliminating speckle noise in LDVom signals for damage inspection.

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“…Laser Doppler vibrometer (LDV) is a popular far-field vibration measurement instrument, providing accurate measurements of velocity in challenging applications. The principle is the proportional Doppler frequency shift to a surface that occurs when light is scattered by a moving surface and an exhaustive introduction of LDV systems is given in reference [5]. Both near and far field transducers are very and even extremely expensive for a single channel.…”

Section: Introductionmentioning

confidence: 99%

Orthogonal On-Rotor Sensing Vibrations for Condition Monitoring of Rotating Machines

Xu¹,

Tang²,

Feng³

et al. 2021

JDMD

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Thanks to the fast development of Micro-Electro-Mechanical Systems (MEMS) technologies, MEMS accelerometers show great potentialities for machine condition monitoring. To overcome the problems of a poor signal to noise ratio, complicated modulation, and high costs of vibration measurement and computation using conventional Integrated Electronics Piezo-Electric (IEPE) accelerometers, a triaxial MEMS accelerometer based On-Rotor Sensing (ORS) technology was developed in this study. With wireless data transmission capability, the ORS unit can be mounted on a rotating rotor to obtain both rotational and transverse dynamics of the rotor with a high signal to noise ratio. The orthogonal outputs lead to a construction method of analytic signals in the time domain, which is versatile in fault detection and diagnosis of rotating machines. Two case studies based on an induction motor were carried out, which demonstrated that incipient bearing defect and half broken rotor bar can be effectively diagnosed by the proposed measurement and analysis methods. Comparatively, vibration signals from transitional on-casing accelerometers are less capable of detecting such faults. This demonstrates the superiority of the ORS vibrations in fault detection of rotating machines.

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Continuous Scanning Laser Vibrometry: A raison d’être and applications to vibration measurements

Cited by 43 publications

References 90 publications

Comparison of three full-field optical measurement techniques applied to vibration analysis

Comparison of three full-field optical measurement techniques applied to vibration analysis

Removing speckle noise from the signals of a laser Doppler vibrometer on moving platforms (LDVom) by ensemble empirical mode decomposition

Orthogonal On-Rotor Sensing Vibrations for Condition Monitoring of Rotating Machines

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