Effects of process-induced residual stress and geometric characteristics on pressure-resisting capability of corrugation in primary barriers of liquefied natural gas carriers

The primary barrier of a liquefied natural gas (LNG) carrier generally has a corrugated shape, so as to withstand thermal shrinkage at cryogenic temperatures. Over the years, studies have been actively performed to improve the performance of the primary barrier through structural analysis. However, when analyzing the pressure-resisting capability of the corrugation, previous studies have not considered the residual stress generated during the forming process of the corrugation. This can lead to an overestimation of the pressure-resisting capability of the corrugation. In this work, the pressure-resisting capabilities of the corrugation were evaluated by considering the residual stress generated during the deep drawing process of the corrugation; the initial buckling mode was also considered through a linear buckle analysis based on a finite element analysis. Universal hydraulic test equipment was developed for measuring the pressure-resisting capabilities of corrugations of various sizes. By comparing the analytical results from the experiments, it was confirmed that the pressure-resisting capability of the corrugation decreased by 16% when the residual stress and initial buckling mode were considered simultaneously. We believe that this study can be used as a reference to present guidelines when setting design parameters to improve the pressure-resisting capability of a primary barrier.