Modal Parameters Identification Method Based on Wavelet Transform and Singular Value Decomposition

Abstract:

A novel modal parameters identification method based on wavelet transform and singular value decomposition is proposed. Assuming that the structural system is timeinvariant and the ambient excitations are white noise, the covariance response of structural accelerations were calculated from response data measured at multiple locations of the structure; and wavelet transform was imposed to obtain the wavelet coefficient matrix of the covariance response.Then the singular value decomposition was adopted to decompose the wavelet coefficient matrix at each wavelet scale, and the modal parameters could be identified exactly from the singular value and singular vector.The formulations of the proposed method were derived and the method was verified by numerical simulation using 3 DOF structure.The results show that the method can be used to identify the modal parameters of multidegree of freedom structure and the accuracy is better than that using a conventional wavelet transform method.