Acoustic emission technique for momitoring stay cable fatigue damage evolution of multi-aged bridge

Acoustic emission(AE) technique was used to monitor the fatigue damage evolution process of stay cables in bridge systems. The relation between stress and strain was gained through tensile test for corroded and non-corroded steel wires, and the results show that the mechanical performance of corroded cable experiences great change. The changing process of AE characteristic parameters during the whole fatigue damage period was obtained. It is found energy cumulative parameters of AE can be used to accurately describe the fatigue damage evolution of multi-aged stay cable. Based on wavelet singularity theory, in each stage of AE, the burst signal was obtained and its time-frequency distribution was achieved through wavelet and FFT analysis. According to the analysis results, failure modes in each phase and types of acoustic emission source can be then easily determined. The characteristics of waveform, types of damages, and frequency distribution of multi-aged stay cable in different damage phases were collected.