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Shock and Vibration
Volume 9, Issue 1-2, Pages 43-56
http://dx.doi.org/10.1155/2002/723561

Linear and Nonlinear Damage Detection Using a Scanning Laser Vibrometer

Steve Vanlanduit,1 Patrick Guillaume,1 Johan Schoukens,2 and Eli Parloo1

1Department of Mechanical Engineering (WERK), Brussel, Belgium
2Department of Electrical Engineering (ELEC), Brussel, Belgium

Received 25 March 2002; Revised 25 March 2002

Copyright © 2002 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Because a Scanning Laser Vibrometer (SLV) can perform vibration measurements with a high spatial resolution, it is an ideal instrument to accurately locate damage in a structure. Unfortunately, the use of linear damage detection features, as for instance FRFs or modal parameters, does not always lead to a successful identification of the damage location. Measurement noise and nonlinear distortions can make the damage detection procedure difficult. In this article, a combined linear-nonlinear strategy to detect and locate damage in a structure with the aid of a SLV, will be proposed. To minimize the effect of noise, the modal parameters will be estimated using a Maximum Likelihood Estimator (MLE). Both noise and nonlinear distortion levels are extracted using the residuals of a two-dimensional spline fit. The validation of the technique will be performed on SLV measurements of a delaminated composite plate.