Instantaneous frequency tracking method for composite cable-stayed bridge

This paper presents an instantaneous frequency (IF) tracking method based on conjugate-pair decomposition, and describes a signal filtering methodology that is employed to eliminate unwanted frequencies. The proposed methodology is verified and compared with Hilbert-Huang transform method by numerical simulation, steel beams and composite cable-stayed bridge experiment. The results show the proposed method has good robustness, adaptability and anti-noise capability which can be used to accurately extract the instantaneous frequency in complex environments; in addition, the extracted frequencies are close to each other using conjugate-pair decomposition and Hilbert-Huang transform. Moreover, the proposed method may be further applied in structural damage identification.