Ultrasonic damage detection with WPT

Non-destructive evaluation technique has been proved to be able to identify microscopic material degradation based on various nonlinear effects of ultrasonic wave propagation in structures. Wavelet transform becomes a promising method, due to its ability to analyze signal with multi-resolution. However, the damage detection results with the conventional wavelet transforms are usually dissatisfied because of the signal complexity and noises. In the present study, a novel damage feature parameter is proposed based on the signal energy of wavelet packet transform (WPT). With the proposed feature parameter, the damage detection results can be obtained. In addition, the simulation results show that the detection of crack with the present method is robust under low SNR environment.