An outline of the application of reliability based techniques to structural design and assessment of submarines and other externally pressurised cylindrical structures

The paper outlines the potential application of a general purpose finite element program (ABAQUS) together with reliability based methods in the structural design and analysis of externally pressurised vessels. The approximate closed form solutions validated through linear finite element models are used in reliability based methods, deriving partial safety factors for direct use in design. It is hoped to extend the analysis to the non-linear range in which material non-linearity, shape imperfections and mode interaction effects will be taken into account. Investigations on complex geometries, innovative materials and deeper operation pressures could be guided by such analytical methods, hopefully reducing the number of costly experiments required. These methods could also be used to assess the safety of in-service structures, as well as the evaluation of the most important variables which influence their failure.