Analysis For The Dynamic Characteristics Of Large Storage Tanks

Tanks belong to the thin-walled structure,they are often used to store toxic,flammable and explosive liquid medium,if the anti-seismic is not fully considered in the design,once the earthquake breaks out,it will lead to serious disaster,and the consequence is unimaginable.Due to the large-scale storage and thin-wall of tanks,which makes the stability of the wall of tanks is poorer,we should pay more attention to the anti-seismic research.In the anti-seismic research of tanks,researchers also consider that tanks have larger strength reserve on the vertical load,so they often give more consideration to the horizontal earthquake incentive issue.However,the actual seismic records show that some places(especially the region near the epicenter),the peak value in the direction of vertical acceleration may exceed the peak value in the direction of horizontal acceleration,it is an urgent need to research the dynamic characteristics of the large scale tanks and analysis of seismic response.In the paper,I took a large vertical-floating tank wich was the largest tank builded in Yizheng distribution station as the object to study,analyzed the static strength on the condition of that we considered the edge effect of hydrostatic pressure and variable wall thickness and the plate with edge plate joint.Because of the characteristic coefficient of seismic response of the tank has a huge impact to the anti-seismic research,so I carried out the modal analysis of the system,and it shows that the natural frequency of the system is extremely concentrated.In order to get the better achievement,I carried out the analysis of the earthquake response.Including the following aspects:the analysis of the hydraulic pressure of the large no-anchored tank when it was stimulated by horizontal and vertical seismic wave.Taking into account the stress of the frist lap from the tank bottom lap,a researcher firstly proposed the theory method on the basis of combining advantages and disadvantages of cylindrical shell theory method.In the paper,I combined testing data from practical engineering to validate its rationality;I researched dynamic characteristics of solid-liquid coupling system of the large scale tank,and studied the influence by different factors wich were the diverse level of liquid medium and the floating roof.Additionally,I adapted the transient module of the finite element software to complete the analysis of the seismic response,acquired the distribution and variation of displacement and stress during the earthquake,and then compared with the calculated results.Finally,I summarized the content of this research and proposed further research which was closely related with this article.