Detection of delamination damage in composite plates using energy spectrum of structural dynamic responses decomposed by wavelet analysis

Damage detection of local and tiny delamination in a laminated composite plate is studied in this paper using piezoelectric patches embedded in composite plate and the energy distribution of structural dynamic responses decomposed in various frequency bands by wavelet packet analysis. This method is based on energy distribution of structural vibration sub-signal and can be in situ implemented using a few piezoelectric patch sensors and actuators embedded in the composite plate. The obtained results show that the method for structural damage detection proposed in this paper is much more sensitive than the existing methods. Using this method, a delamination area of only 0.13% of the total area of the composite plate may be detected. The results show that numerical simulation are quite consistent with experiment results.