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Introduction
LNG cargo pump tower has been used for the handling of LNG. It consists of pipes and pumps for loading and discharging the liq-uefied cargo and tubular members for supporting the structure. LNG cargo pump is a vertical submerged centrifugal pump, designed to load and unload the liquefied gas in a cryogenic temperature (Det Norske Veritas, 2006; Lloyd’s register, 2008). The design of the LNG cargo pump should produce a deep-well pump able to handle the cargoes in the temperature of 165 C. Also, the pump should be assembled in materials which can resist the cryogenic environment since the pump experiences the excessive thermal load, vibratory load, and impact load.

引言

LNG船液货泵塔已用于液化天然气的处理。它包括装卸货物和管状构件的液体，这些工作的基础支撑结构的管道和泵。LNG船液货泵是立式液下离心泵，设计荷载和在低温下卸载液化气（挪威船级社，2006；劳埃德的寄存器，2008）。LNG船液货泵的设计应产生一个深井泵能够处理货物在165 C的温度，泵应安装在能抵抗低温环境，因为泵的经验，热负荷过大，材料的振动荷载，冲击荷载。

Stainless steel alloy i.e. SUS304 has been used for the membrane type LNG cargo containment because of its structural capacity for sloshing loads. The sloshing loads concentrate on the containment membranes and pipes. Therefore, there are less loads with the pump than there are with the pipes or cargo containment membrane. The concern of pump is the increased thermal cycling and vibratory loads. As the components of the pump such as pump casing, motor frame, etc., aluminum alloy cast (AC4C-T6) has been a subject of discussion in several LNG pump manufacturers.

SUS304不锈钢合金即已用于薄膜型LNG货物围护由于其晃荡载荷的结构能力。液体晃荡载荷集中在安全壳膜和管。因此，有与泵比有管道或货物无膜负载。泵的关注增加的热循环和振动载荷。作为泵的泵壳等组成，电机架，等，铝合金铸件（ac4c-t6）已在几个LNG泵制造商讨论主题。

Aluminum alloys have attracted attention in the vehicle compo-nents that are operated in high temperature or cryogenic temper-ature. The alloy has good castability, high corrosion resistance, good machinability, and good thermal conductivity which prevents local overheating. Aluminum alloys have also have attracted special interest with respect to applications requiring high cryogenic toughness and reliability such as the components of vehicles
(Ishihara & McEvily, 2002 ). These characteristics make the aluminum alloy be used for the pump instead of stainless steel although it has less strength than the stainless steel. Furthermore, the stainless steel is more expensive than the AC4C-T6. However, the material properties of AC4C-T6 have not yet been investigated to LNG pump industry’s satisfaction. To evaluate the strength of the material, experimental data from several specimen tests should be used in failure and strength analysis of the pump under the cryogenic and the expected loads.

Present study investigates the features of material model of AC4C-T6 under monotonic load and cyclic load. Not only the experimental data but also a relationship between the stress and strains is investigated to find the appropriate material models. The model includes Young’s modulus and material nonlinearities of plasticity. To investigate the tensile properties and cyclic properties of AC4C-T6 in the cryogenic temperature and room temperature, uni-axial and cyclic tests were conducted. FEA is used to obtain a material model that is a proper description of the test data. FEA makes it possibl本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。