LNG 储罐在地震作用下弹性罐壁 Mises 应力理论解

摘要

以典型弹性壁LNG储罐结构为研究对象,探讨了该类结构在地震作用下的结构响应. 对比分析了反应谱理论与欧洲规范枟EN1998-4枠关于弹性壁储罐结构的地震动动水压力,提出并应用曲面拟合方法将该动水压力拟合为三角函数的组合形式. 从薄壳结构理论出发,应用拟合的动水压力与静水压力的叠加,给出了在地震作用下该类结构的Mises应力解. 通过比较本文提出的罐壁Mises应力理论解与ABAQUS耦合欧拉—拉格朗日( CEL)的算法结果,验证并表明了本文理论简化解具有较高的计算精度.%Seismic responses of the typical LNG inner storage tank with the capacity of 160 000 cubic meters are studied under seismic excitations.The response spectrum theory is compared with those in European standard EN1998-4 about the hydrodynamic pressure in the earthquake motion of storage tank with elastic walls.And on this basis, this paper proposes a method of curved surface fitting and applies it to fit such hydrodynamic pressure into a combinatory form of trigonometric function.By the superposition of fitted hydrodynamic pressure and hydrostatic pressure, the Mises stress solution of similar structure under the earthquake action is given based on the thin shell theory.The precision of the theoretically simplified solution in this paper is proven by comparing results from theoreti-cal solution of Mises stress in the tank wall with that from ABAQUS coupled Eulerian-Lagrangian ( CEL) analysis.