Wavelet-based technique for structural damage detection

A wavelet-based technique is proposed for structural damage detection and health monitoring. In this technique, characteristics of representative vibration signals under the wavelet transformation are examined for damage identification. The proposed method is based on only the output data without the need for measuring the excitation forces, any modal identification or numerical models. The method is described theoretically and verified both experimentally and numerically using a railway steel bridge. The applicability of utilizing piezoelectric actuators for exciting large structures such as steel bridges is also investigated in this paper. Several damage scenarios were introduced to the test structure by removing bolts from some stiffeners located on the web of the main girder. Similar damage scenarios were introduced to the finite element model of the test structure. The results indicate that the current approach can identify the location of small damage effectively. The proposed method combined with the use of piezoelectric actuators is shown to be very suitable for continuous health monitoring of steel bridges. Copyright © 2009 John Wiley & Sons, Ltd.