Defect detection and localization in hydrogen pipelinesusing acoustic emission technique

The structural integrity of hydrogen pipelines is critical for ensuring the safe and efficient transportation of hydrogen as a clean energy carrier. Over time, potential defects such as hydrogen embrittlement-induced cracks, weld defects, and leakages may occur along pipelines stretched across long distances. To monitor the health of such infrastructures in real-time, acoustic emission (AE) monitoring has emerged as a promising non-destructive evaluation (NDE) and passive method. This study investigates the application of AE technique to detect and localize controlled defects along metal pipelines. Experiments were conducted on a steel pipe specimen mounted with AE sensors laid out in a triangulation array, and a controlled AE source. The AE signals generated by the source were analysed to identify characteristic parameters, such as amplitude, frequency, rise time, counts, and signal duration for early defect detection. With the sensors laid out in an array configuration, the AE sources can also be accurately localised along the pipe walls. Results demonstrate that AE can effectively in-situ monitor and localise defects in pipeline, providing valuable insights into the infrastructure integrity. Furthermore, triangulation algorithms were employed to improve defect classification and localization accuracy. With the accurate localisation of an AE sensor array, non-destructive testing (NDT) methods can be supplemented for a more thorough inspection and characterisation of the localised defect. This work highlights AE testing as a viable, real-time monitoring tool for enhancing the safety and reliability of hydrogen pipeline infrastructure.