Time-variant reliability analysis of pressure-resistant structures of disk-shaped underwater gliders in corrosive environments

Corrosion considerably affects the safety and life cycle of underwater vehicles. Using the linear buckling analysis method, the mesh sensitivity of the pressure hull of the glider was analyzed to determine the size of the finite element unit. Furthermore, the random uniform corrosion model of the pressure hull was also developed, and the statistical characteristics of time-variant degradation of ultimate strength were determined. In addition, the limit state equation was constructed based on the hydrostatic pressure and ultimate strength, and the instantaneous and time-variant reliability of the pressure hull under multiple working conditions were calculated using the Joint Committee on Structural Safety method, time discretization method, and out-crossing rate methods. The results revealed that corrosion attenuated the reliability every year. Among the several methods compared in this study, the PHI2+ method exhibited the best computational efficiency and accuracy, and the time-variant reliability analysis considerably improved the life prediction accuracy.