Method of modal identification based on wavelet transform in LTI system under non-stationary random excitation

Modal parameters' identification of linear system to non-stationary random excitation has been a hot research topic in recent years. A new synthesis stationary signal y(b) based on wavelet transform of original response x(t) and wavelet coefficients' orthogonality is presented in this paper. The new signal, which satisfies structural motion equation, instead of original response, is used in identifying the modal parameters of non-stationary linear system, combined with the method of modal identification under stationary random excitation. The numerical results show that the method can remove the non-stationary of output signal under non-stationary random excitation to a certain extent.