Burst pressure prediction and failure mechanism analysis of composite overwrapped pressure vessels under cryogenic conditions

Composite overwrapped pressure vessels (COPVs) for storing cryo-compressed hydrogen face significant safety challenges under cryogenic high-pressure conditions. While previous studies have primarily evaluated COPV safety through empirical testing, comprehensive analyses of their failure mechanisms remain limited. This study investigates the cryogenic burst pressure and failure mechanisms of COPVs using a finite element model. The results indicate that under cryogenic conditions, matrix failure in the composite layers occurs at a lower internal pressure, which is detrimental to the vessel's burst pressure. Conversely, at cryogenic temperatures, the composite develops longitudinal compressive stresses that partially offset the tensile stresses induced by internal pressure, and the composite strength is simultaneously enhanced. Ultimately, the combined effect of these three factors leads to an enhanced burst pressure for COPVs at cryogenic temperatures. • A progressive damage failure analysis model for the COPV was established. • Composite layers of COPVs show longitudinal compression at cryogenic temperatures. • Matrix damage promotes load transfer to the fibers during pressurization. • The burst pressure of COPVs increases under cryogenic conditions.