Dynamic Response Analysis Of Large Storage Tank Group System Based On Additional Mass Method

With the rapid growth of our country’s energy demand and strategic reserves,storage tanks are developing in the direction of large-scale and group tanks.China is a country with frequent earthquakes,and strong earthquakes can cause obvious deformation of the foundation soil.Due to the interaction between the tank and the soil,as well as between the adjacent tanks through the soil,it is very easy to cause damage to the storage tank during an earthquake,resulting in oil leakage,fire and explosion,and serious damage to people’s lives and property.In our country’s current storage tank design codes and standards,most of the interactions between soil tanks and the cross interaction between adjacent tanks are not considered,but the seismic design is based on the assumption of rigid foundation.The seismic design of storage tanks should consider the group tank effect and the soil-structure interaction effect.It is very important to ensure the safe operation of the storage tank.Based on this,this article carried out the following work:1.First,it summarizes the common analysis methods of the seismic response of storage tanks.Then based on the assumption of rigid foundation,the mass spring tank model,the tank model based on the additional mass method,and the fluid-structure coupled tank model using the fluid element method were established using ANSYS software.With the three seismic waves of El-centro wave,Qian’an wave and Shanghai artificial wave as input,the dynamic characteristics and seismic response analysis of the three calculation models were carried out.The natural frequency of each model and the difference with the theoretical calculation results were compared.From the calculation accuracy Considering comprehensively the safety margin and calculation efficiency,this paper adopts the additional mass method to study the seismic response of the storage tank model.2.The equivalent linearization method is used to consider the nonlinear characteristics of the soil under the action of strong earthquakes.Through the secondary development of ANSYS software,the realization of equivalent linearization model in ANSYS software was studied,and a processing method of selecting representative units in different areas of the site for linear iteration was proposed.The results showed that this method can be applied to large storage tanks-Seismic response analysis of soil interaction system.3.The finite element model of the storage tank-soil interaction system is established based on the additional mass method,and the improved equivalent linearization method is used to consider the nonlinearity of the soil.Compared with the seismic response results of the storage tank based on the assumption of rigid foundation,the soil is studied.-The influence of structure interaction effect on the seismic response law of storage tank.At the same time,the change law of the seismic performance of the storage tank caused by the properties of the soil material(linear elasticity and nonlinearity)is analyzed.4.Under the previous ground motion input,the finite element model of the interaction system between the group tank and the soil was further established,and the deformation,stress and buckling instability of the tank wall in the group tank site were studied,and compared with the situation when only a single tank was considered.The influence of the group tank effect on the seismic response law of the storage tank is analyzed,and the location of the tank wall where the buckling failure occurs is determined,which provides a reference for the seismic design of large storage tanks.