Identification of modal parameters of a system with high damping and closely spaced modes by combining continuous wavelet transform with pattern search

First, the free-decay response (FDR) of a system is established using all the initial identification results obtained by continuous wavelet transform (CWT) method. Then, the initial identification results are corrected using the pattern search method with the residual sum of squares between the FDR and the actually measured free-decay signal as the objective function. An integrated method based on both CWT and pattern search is thus developed for more accurate identification of modal parameters of a system with high damping and closely spaced modes. Both simulation and experimental results indicate that the proposed method can be used to achieve more accurate identification of modal parameters in a shorter sampling period of time.