Reliability Analysis Of Ultimate Strength Of Submarine Sphere-cylinder Combined Pressure Shell

Sphere-cylinder combined shell is the main form of submarine structure. Submarine is mainly subjected to the hydrostatic pressure during navigation underwater. As a submersible combat weapon, serious consequences will cause if the structure is damaged, so, to ensure the safety of submarine structure is very important. The design of submarine pressure hull usually adopts the method of certainty while the submarine's mechanical properties can show better by using the reliability method.This paper firstly describes the uncertainty factors of submarine pressure hull. Five failure modes are established by analyzing the key parts of the ring stiffened cylindrical shell and the specification. The distribution characteristics of random variables in failure mode are studied as well as the correlation coefficient between failure modes, then, the reliability of the whole system is determined by the series system and the bound method. Finally,the reliability of the submarine ring stiffened cylindrical shell is calculated and analyzed by using different reliability analysis methods.Calculation results of submarine strength and stability by classical formula will produce deviation as ring stiffened cylindrical shell and spherical shell of submarine will be affected by geometric imperfections and residual stress. Instability between ribs and overall instability of ring stiffened cylindrical shell will also have a mutual impact. In this paper, the reliability analysis method of ultimate strength of submarine Sphere-cylinder Combined Pressure Shell is presented, which can be used to evaluate the safety of submarine structure more accurately.