Abstract: In order to ensure the normal operation of manned submersible and the divers′ life safety in deep sea environment, the pressureshell of the 4500 m manned submersible was taken as the research object, and the fatigue analysis was carried out based on structural reliability theory and finite element analysis method, the fatigue reliability was calculated based on stressinterference model. The calculation results show that the shell is safe within 4000 service cycles. Considering the influence of stress concentration at the opening of the shell, the fatigue reliability index was reduced from 4.555 2 to 2.034 5, so necessary reinforcement measures should be taken to reduce the stress concentration at the opening position when designing the structure of the pressure submersible shell. This study provides a theoretical reference for structural design and fatigue life estimation of manned submersible pressure shells.

Key words: manned submersible, pressure shell, structural strength, fatigue reliability