Fibre optic acoustic emission sensor system for hydrogen induced cold crack monitoring in welding applications

A fibre optic acoustic emission method to monitor hydrogen induced cold crack activities during welding is presented in this paper. A high sensitivity fiber Bragg grating (FBG) based acoustic emission (AE) measurement system is developed to monitor the cold crack induced AE events during a titanium aluminide alloy welding using gas tungsten arc welding method Frequency ranges of the AE where cold cracking occurs in the metal also has been evaluated. The measured frequency components of the AE events were within 270 kHz. The results of this feasibility study shows the potential of FBG based AE detection method to accurately predict the defects in welding, which will improve the quality of the final weld product in applications where higher welding standards are required.