Full-field mode shape estimation of a rotating structure subject to random excitation using a tracking continuously scanning laser Doppler vibrometer via a two-dimensional scan scheme

2022 ◽  
pp. 108532
Author(s):  
L.F. Lyu ◽  
W.D. Zhu
Keyword(s):  
Mode Shape ◽  
Laser Doppler Vibrometer ◽  
Random Excitation ◽  
Scanning Laser ◽  
Two Dimensional ◽  
Shape Estimation ◽  
Field Mode ◽  
Full Field ◽  
Scanning Laser Doppler Vibrometer ◽  
Rotating Structure

scholarly journals Measurement of Translational and Angular Vibration Using a Scanning Laser Doppler Vibrometer

1996 ◽  
Vol 3 (2) ◽  
pp. 141-152 ◽  
Author(s):  
A.B. Stanbridge ◽  
D.J. Ewins
Keyword(s):  
Frequency Response ◽  
Laser Doppler Vibrometer ◽  
Random Excitation ◽  
Laser Doppler ◽  
Scanning Laser ◽  
Scanning Laser Doppler Vibrometer ◽  
Straight Line ◽  
Angular Vibration ◽  
Freely Suspended ◽  
Drive Signals

An experimental procedure for obtaining angular and translational vibration in one measurement, using a continuously scanning laser Doppler vibrometer, is described. Sinusoidal scanning, in a straight line, enables one angular vibration component to be measured, but by circular scanning, two principal angular vibrations and their directions can be derived directly from the frequency response sidebands. Examples of measurements on a rigid cube are given. Processes of narrow-band random excitation and modal analysis are illustrated with reference to measurements on a freely suspended beam. Sideband frequency response references are obtained by using multiplied excitation force and mirror-drive signals.

Operational modal analysis of a rotating structure subject to random excitation using a tracking continuously scanning laser Doppler vibrometer via an improved demodulation method

2021 ◽  
pp. 1-30
Author(s):  
Linfeng Lyu ◽  
Weidong Zhu
Keyword(s):  
Image Processing ◽  
Laser Doppler Vibrometer ◽  
Random Excitation ◽  
Processing Method ◽  
Rotating Beam ◽  
Scanning Laser Doppler Vibrometer ◽  
Rotating Structure ◽  
Fan Blade ◽  
Measured Response ◽  
Demodulation Method

Abstract A new operational modal analysis (OMA) method that is based on a rigorous nonuniform rotating beam vibration theory and an image processing method is developed to estimate modal parameters (MPs) of a rotating structure (RS) under random excitation using an improved demodulation method. The solution to the governing equation of a nonuniform rotating beam is derived, which can be considered as the response of the beam measured by a continuously scanning laser Doppler vibrometer (CSLDV) system. A recently developed tracking CSLDV system can track and scan the RS. The image processing method determines the angular position of the RS so that the tracking CSLDV system can sweep its laser spot along a time-varying scan path on it. The improved demodulation method obtains undamped mode shapes (UMSs) of the RS by multiplying its measured response by sinusoidal signals with its damped natural frequencies (DNFs) obtained from the fast Fourier transform of the measured response. Experimental investigation of the OMA method using the tracking CSLDV system is conducted, and MPs of a rotating fan blade (RFB), including DNFs and UMSs, with different constant speeds and its instantaneous MPs with a non-constant speed are estimated. Estimated first DNFs and UMSs of the stationary fan blade and RFB are compared with those from the lifting method that was previously developed by the authors.

scholarly journals A Continuous Scanning Laser Doppler Vibrometer for Mode Shape Analysis

2002 ◽  
Vol 35 (2) ◽  
pp. 481-486
Author(s):  
Jongpil La ◽  
Jieun Choi ◽  
Jinpyo Hong ◽  
Semyung Wang ◽  
Kyoungsuk Kim ◽  
...  
Keyword(s):  
Shape Analysis ◽  
Mode Shape ◽  
Laser Doppler Vibrometer ◽  
Laser Doppler ◽  
Scanning Laser ◽  
Scanning Laser Doppler Vibrometer ◽  
Continuous Scanning
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