Experimental Study About Dynamic Response Of Unanchored Model Tank With Floating Roof Under Lateral Earthquake Excitation

Unanchored oil tanks with floating roof are the key equipments of national strategic oil storage reservoir, which are important safeguard to protect national economic security. With the large-scalization of oil storage tanks, the potential risk is increasing; especially in the earthquake condition, some unanchored oil tanks with floating roof are damaged. To ensure the safety of unanchored oil tanks with floating roof, it is necessary to do some further research on the dynamic response of oil tanks in seismic.In the past research, many scholars treat the tank as no roof and ignore the impact of floating roof on oil tank. However, floating roof has a great effect on the dynamic response of oil tanks, especially for liquid sloshing and the stress of tank wall where the floating roof locates. Therefore, based on large unanchored oil tanks with floating roof, experimental research on the dynamic response of unanchored model tank with and without floating roof under lateral seismic excitation has been carried out. At the same time, numerical simulation software--Adina is used to research on the dynamic response of the unanchored model tank with and without floating roof, by comparing the numerical results with experimental results, some useful conclusions have been obtained. The main research work in the paper is concluded as follows:(1) Summarize the experimental and numerical achivements of seismic research on unanchored oil tanks with floating roof at home and abroad, propose some technical problems and hot issues to be resolved.(2) Introduce the determining method and basic theory of seismic waves used in the experiment; describe basic theory of fluid-structure coupling in finite element method.(3) Experimental research on the sesmic response of the model tank on large three-dimensional seismic platform. By inputing the lateral seismic excitation, the X-direction acceleration, tank uplift, X-direction displacement, sloshing wave height and strain of the model tank are obtained. It can be found that the dynamic response of the model tank with floating roof and the model tank without floating roof is significantly different, for example, floating roof can significantly decrease the sloshing wave height and reduce vibration after earthquake, so it is not comprehensive to research on the sesmic response of large oil tank without considering the impact of floating roof.(4) Numerical simulation software--Adina is used to build the numerical model of the model tank. The dynamic response analysis of the model tank with and without floating roof is carried out. By comparing the numerical results with the experimental results, it is found that the differences between numerical and experimental results of X-direction acceleration and sloshing wave height are small, but the differences between numerical and experimental results of tank uplift and X-direction displacement are a little big, and the reason is analyzed.