Research on hydrogen-indulced damage detection technology using shear horizontal SH ₀ mode nonlinear ultrasonic guided waves

Hydrogen-enriched natural gas pipelines are vulnerable to hydrogen-induced damage, such as cracking, over time, posing safety risks. Regular inspection of high-grade steel pipelines in hydrogen-rich environments is crucial. Ultrasonic testing, known for its sensitivity to early internal defects in plate-like structures, is a promising method for detecting such anomalies. However, its effectiveness in detecting hydrogen-induced damage in pipelines has not been fully validated. This study proposes using Shear Horizontal (SH0) mode nonlinear ultrasonic guided waves for detecting hydrogen-induced damage. X80 steel was selected for the research, with pre-tensile and electrochemical hydrogen charging experiments to prepare the samples. Nonlinear ultrasonic testing with SH0 guided waves was conducted on samples with varying damage levels to observe changes in the ultrasonic nonlinear coefficient during the damage process. A microcrack cluster damage model was developed using MATLAB and COMSOL, combining finite element analysis and 3D X-ray Microscopy (XRM) to explore the relationship between nonlinear ultrasound and hydrogen damage. Results show that as cracks propagate, the nonlinear coefficient first increases and then decreases. Simulations reveal the propagation mechanism of nonlinear ultrasound in hydrogen-induced damage, providing theoretical support for enhanced detection. This approach improves the ability to detect hydrogen-induced damage in pipelines.