张  恒¹，  谢  剑^1,2
    （1天津大学建筑工程学院，天津300072；2 滨海土木工程结构与安全教育部重点实验室（天津大学），天津300072）

[摘要] 为分析大型LNG低温储罐的振动特性，根据实际工程情况分为空罐和满罐两种工况，利用ANSYS软件对处于空罐和满罐两种状态下的储罐分别进行了合理建模和模态分析。从理论分析出发，考虑了流固耦合问题，较为精确地分析了两种工况下的储罐的自振特性。结果表明：液体的存在使得储罐的固有频率降低；在满罐情况下，液体对于低阶频率的影响大于对高阶频率的影响。为储罐的安全使用提供了可靠的依据，并为进一步的动力响应分析打下了基础。
[关键词] LNG储罐；模态分析；流固耦合；动力响应
中图分类号：TU378.7    文献标识码：A  文章编号：1002-848X(2011) S2-0123-04

    Modal analysis of large-sized LNG low-temperature tanks
    Zhang Heng¹, Xie Jian^1,2
    (1 School of Civil Engineering, Tianjin University, Tianjin 300072, China; 2 Key Laboratory of Coast Civil Structure Safety ( Tianjin University),  Mirustry of Education,  Tianjin 300072,  China)

Abstract: As a large special structure, the seismic response analysis of tanks has profound strategic significance. In order to analyze vibration properties of large-sized LNG low-temperature tanks, modal analysis of tanks under the conditions of the slack tank and fullliquid state were performed through reasonable modeling by ANSYS. Beginning with the theory of fluid-solid coupling, the free vibration properties of tanks under the two conditions were analyzed precisely. The result shows that, in the full liquid state, the tank's free vibration is lower. In the full liquid state, the influence of the liquid on the low-frequency vibration is more apparent. This method has provided the reliable basis for the safety using of tanks, and has built the base of the further dynamic response analysis.
Keywords: LNG tanks; modal analysis; fluid-solid coupling; dynamic response