Simulation of creep-fatigue crack growth in aluminum alloy layers of hydrogen storage cylinders

Hydrogen storage cylinders are crucial to hydrogen production and storage systems. During the service of the hydrogen storage cylinders, they undergo frequent hydrogen charging, dwelling, and discharging. The ceep-fatigue problems in the liner of the cylinders typically made of AA6061-T6 should be taken into account. In this paper, the creep-fatigue crack growth experiments on the compact tension specimens of AA6061-T6 are conducted. Based on it, simulations of creep-fatigue crack growth in the liner under six different dwell conditions are performed. Comparative analysis of the stress intensity factor range curves reveals that under the same working conditions, as the dwell time and initial crack depth increase, accelerating the crack growth rate leads to the life decreasing of the liner, thereby hastening the failure of the liner and the overall structure, which should be considered during life assessment.