大型立式隔震储液罐的地震响应数值模拟

Numerical simulation on seismic response of large vertical isolated liquid storage tank

为研究储液罐在双向地震波激励下的地震响应,以15×10^4 m^3立式浮放隔震储液罐为对象,利用有限元软件ADINA考虑接触非线性,进行大型立式浮放储罐隔震响应数值分析。整个系统主要分为基础隔离部件和液体-结构相互作用子系统两部分,分别利用壳单元和势流体单元模拟罐体结构和液体区域,并用弹簧-阻尼系统等效代替三维隔震。利用Bathe积分法对储液罐进行提离响应、加速度时程、液体晃动波高、罐壁应力变化、基底剪力及倾覆力矩分析。结果表明:在El Centro地震波激励下,隔震前罐底发生了提离且提离区域呈“月牙形”,隔震后提离现象消失。在储液罐中安装隔震层可以有效降低加速度、罐壁应力、基底剪力及倾覆力矩等动力响应,但隔震后储液罐液面晃动的波高有所增大。研究成果可为储液罐的隔震设计提供参考。

In order to study the seismic response of liquid storage tank under bidirectional seismic excitation,the 15×10^4 m^3 vertical unanchored liquid storage tank was taken as the object,and numerical analysis on seismic response of vertical unanchored tank was conducted with the finite element software ADINA,considering the contact nonlinear.The whole system was mainly divided into two parts,i.e.,the basic isolation components and the liquid-structure interaction subsystem.The structure and liquid region of the tank were simulated with the shell element and potential fluid element respectively,and the three-dimensional isolation was equivalently replaced by a spring-damping system.Subsequently,analysis of uplift response,acceleration time history,liquid sloshing height,wall stress change,base shear and overturning moment was carried out for the liquid storage tank with Bathe integration method.The results show that:under the excitation of El-Centro seismic wave,the tank bottom is uplifted before seismic isolation and the uplift area is in the shape of“crescent”,which disappears after seismic isolation.Installing a seismic isolation layer in the liquid storage tank could effectively reduce the dynamic response such as acceleration,wall stress,base shear force and overturning moment.However,liquid sloshing height of the liquid storage tank after seismic isolation increases.The research results could provide reference for the seismic isolation design of liquid storage tank.