Nonlinear Structural analysis of membrane-type LNG carrier cargo containment system under cargo static pressure loads at the cryogenic condition with a temperature of −163°C

Abstract

Liquefied natural gas carriers (LNGCs) have become larger in size but without any accompanying increase in the number of cargo tanks, thus resulting in a subsequent increase in both cargo pressure loads and sloshing impact pressure actions. This trend raises the question of whether the cargo containment systems of LNGCs in their existing proportions are strong enough to withstand the abnormal actions that may occur in service. Answering this requires an investigation of possible changes in the structural design of the membrane corrugations in cargo tanks, which essentially necessitates precise analysis of strength performance. The objective of the present paper is to investigate the structural behaviour of membrane-type LNGC cargo containment system under cargo static pressure loads at the cryogenic condition with a temperature of −163°C, while a sequel to the present paper will be reported in a separate paper dealing with structural behaviour under sloshing impact pressure loads. In the present study, ANSYS non-linear elastic–plastic large deflection finite element method is employed for analysing structural behaviour under cargo pressure loads. Important insights obtained from the study are summarised.