A combined crosstalk cancellation method based on wavelet packet denoising and Welch's method for operational transfer path analysis

To increase the accuracy and reliability of the transmissibility function evaluation, a combined crosstalk cancellation method based on wavelet packet denoising and Welch's method for operational transfer path analysis (OTPA) is proposed. Firstly, prior tests are carried out with pulsed excitation, and the signals at reference points are measured concurrently. Secondly, wavelet packet denoising is adopted to process the measured signals, which can effectively reduce the effects of measurement noises and other random errors. Thirdly, Welch's method is adopted to evaluate auto-power spectrums and cross-power spectrums, and thus the prior transmissibility functions can be accurately obtained. Fourthly, a crosstalk cancellation method is proposed and the signals at reference points without crosstalk are obtained. Finally, the crosstalk problem is solved and an efficient and accurate OTPA is obtained. Furthermore, numerical case studies and experimental case studies on a test bed with shell structures are carried out to study comparatively the performances of the proposed method. Generally, this study provides an effective crosstalk cancellation method for OTPA, which can increase the accuracy and reliability of transfer path identification and contribution evaluation, and thus benefit vibration and noise monitoring, reduction and control. (paper)