Pressure Hull Optimization Using General Instability Equation Admitting More Than One Longitudinal Buckling Half-Wave

Abstract

Current design procedures often assume that the critical buckling shape in general instability contains only one longitudinal half-wave. This assumption may be incorrect for optimal hulls if what appears to be a questionable independent frame buckling constraint, often employed in pressure hull design, is relaxed. A method for predicting general instability admitting more than one longitudinal l half-wave is, therefore, adapted to an automated optimal design procedure for the synthesis of frame-stiffened, cylindrical, submersible hulls. Design studies demonstrate that substantial weight reductions are possible for hulls designed for conventional operating depths (around 1000 ft) if ultrahigh-strength steels are utilized.