Frequency identification based on power spectral density transmissibility under unknown colored noise excitation

Abstract

In this paper, a new natural frequency identification method is proposed for the modal parameter identification under an unknown colored noise excitation. The presented method can effectively eliminate the influence of incentive frequency on the identification of the natural frequencies when there are several colored noise excitations applied to the structure. However, it would be cumbersome or even difficulty to determine the natural frequencies when there is only one unknown colored noise excitation applied to the structure. In this paper, a new frequency indicating function using the second singular value of the transmissibility matrices is proposed for the first time to determine the natural frequencies of the structure under only one unknown colored noise excitation. The reason for using the second singular value in theoretically is also a novelty of this paper. The proposed method is verified using a six-degree-of-freedom system and a laboratory plane frame. The results show that the proposed method can effectively eliminate the resonant peak that does not belong to the structural model and is robust to noise.