Leakage Detection in Composite Pressure Vessels Type IV Using Acoustic Emission Testing

Abstract

Composite pressure vessels (CPVs) Type IV, featuring a plastic liner that is fully overwrapped using the filament winding technique, represent the state of the art of pressure vessels on the market. CPVs used for hydrogen storage and transportation may suffer various types of damage, potentially affecting their safe operation as well as their residual useful life. The damage mechanisms in Type IV CPVs may include delamination, matrix cracking, fiber breakage, or failure of the plastic liner. Existing damage may grow under pressurization and depressurization cycles and lead to a catastrophic event, such as burst, causing financial loss and loss of life. This study investigates the use of acoustic emissions (AE) as a non-destructive technique for the detection and localization of leakage in artificially damaged Type IV CPV. Damage was introduced through a low-velocity impact generated by the free-fall of a mass from a predefined height. AE was monitored during an ad-hoc designed experimental setup and pressurization history. Results for a vessel selected from the test set are shown and discussed in the study. The present work has been carried out within a joint research project between the University of Bologna and TÜV AUSTRIA, in collaboration with FABER Industrie.