Delamination detection base on wavelet correlation damage index of time reversal guided wave

The self-focusing ability of Time Reversal Guided Wave (TRGW) is studied in the damage detection of composite laminates. The finite element modelling of delamination is developed to investigate the potential of TRGW as non-based damage detection system. The similarity index and the damage index are used to evaluate the self-focusing ability at different excitation frequencies, based on which the optimal excitation frequency is determined. The wavelet correlation damage index is proposed based on the correlation between the TRWG wavelet coefficients of response signal and excitation wavelet, whose normalised value is taken as the damage index to locate the delamination in the plate with the probabilistic imaging algorithm. Simulation results showed that using the proposed index can accurately image the delamination damage with high-resolution, which would enchance the capability of TRGW-based techniques for damage detecting and imaging.