Feature Extraction of AE Signal in Offshore Platform Tubular Joints Crack Propagation Based on Wavelet Coefficient Energy Theory

Abstract

To identify the fatigue crack propagation of tubular joints in the offshore platform, we applied the wavelet coefficient energy theory to monitor and analyze the acoustic emission(AE) signal of marine structures with typical fatigue crack propagation. Based on typical tubular joints model fracture experiments of the offshore platforms, we successfully extracted the characteristics of AE signals during crack propagation. Further analysis results demonstrated that the elastic wave generated by the crack extension was superimposed by a variety of high frequency signals, and it changed with the evaluation of crack. The variation of wavelet coefficient energy and the change of crack propagation state showed a strong correlation. Thus the characteristics of AE signals can be used to identify different stages of crack propagation accurately, intuitively, and clearly, so as to label the development process of crack.

Crack detection in plastic pipe using piezoelectric transducers based on nonlinear ultrasonic modulation

“…Thereby, crack damage indicator can be extracted to evaluate the damaged condition using this phenomenon. Wavelet energy method, based on wavelet packet analysis has been proven effective in signal processing and damage evaluation [40,41]. In this paper, a wavelet analysis technique is used to extract data of pipe damage states which may indicate the crack damage severity.…”