Estimation of Elastic Buckling Strength of a Non-Spherical Tank in the Partially Filled Condition

A method of estimating elastic buckling strength of a non-spherical tank intended for the use in LNG carriers is presented. Partially filled condition that causes combined meridional tension and circumferential compression is considered. Analytical expression of pre-buckling stress distributions is derived based on membrane shell theory. These stresses are applied to the elastic buckling strength analysis employing Hutchinson’s solution for a toroidal shell segment under similar stress condition. The buckling strength of a spherical shell is highly sensitive to initial shape imperfections, but these are not considered as a most fundamental case. The predicted stress distributions and elastic buckling strength are compared with those calculated by the 3D shell finite element analysis.