Pump Tower Analysis For Membrane-Type LNG Ship Based On The Sloshing Load

Liquefied natural gas (LNG) carrier is a sort of appropriative ship built for the transportation of LNG. The cargo it transits is the liquefied natural gas at the temperature of -163. LNG carrier technology is the most complex and difficult during all the traffic ships and goes by the name of "The bright pearl on imperial crown" in the international shipbuilding field. The design of LNG carrier in China shipbuilding field is still being on the groping phase. Hudong-Zhonghua shipyards has carried on the project of real ship and fetched in the design of ship drove by 147,000 stere steam cooperating with North Atlantic shipyards. At the same time, it has completed the construct of terms required by real ship building and pushed the prelude of super LNG carrier building in China.LNG carrier has the characteristics of high tech, high risk and high additional value. High risk has been paid the most attention. In case there is an accident, it would bring a large expense to human being due to its particularity though there have been few accidents in history.Pump tower of the super LNG ship is in whole scale range of the LNG tank, it is the alleyway for goods and persons entering and leaving. During the voyage of the LNG carrier, the pump tower structure is subject to various loads such as: sloshing load due to liquid motion; inertial and gravity load due to tank motion and inclination and thermal load due to thermal contraction/expansion, its structure requires high reliability, so the structural analysis of pump tower and calculation of loads are not only the foundation work but also one of pivotal techniques for design of the LNG carrier. It is requisite to analyze the ship motions during the lifecycle aiming at ship scale and voyage circumstance and carry through the sloshing analysis, then gained the sloshing loads and assess the strength.This paper combined with the demand of the ABS Guidance Notes, set up the hydrodynamics models of the liquid tank and the pump tower, carried through the sloshing analysis in different loading circumstances when the ship motion is decided. At last, it set up the finite element model of the pump tower and carried through the strength finite element analysis. This paper finds out the sloshing law of the LNG tank and calculates the sloshing loads in different loading circumstances, discusses the influence degree of the sloshing loads to the structure. In addition, this paper has set up a reasonable finite element model of the pump tower, carried through the finite element analysis and received the stress and distortion of the tower in different loading rate, discussed the reason of the distortion. It provides certain help for related design and research for the future.