Study On Seismic Behavior Of LNG Liquid Storage Tank With High Damping Rubber Isolation Bearing

Liquefied natural gas(LNG)is a safe and clean new energy source,and LNG storage tank is widely used.However,under the action of strong earthquake,LNG storage tank is easy to be destroyed,which will cause unmeasurable losses to social economy,environment and life safety.In this paper,the numerical models of high damping rubber isolation tank and non-isolated storage tank was established by the finite element analysis software ADINA,and the research of damping control under near-field earthquake excitation were carried out.The main contents are as follows:(1)The finite element numerical model of 1000m~3 vertical liquid storage tank was analyzed by using finite element software ADINA.The sloshing frequency and mode shape,fluid-solid coupling frequency and mode shape were obtained,and the influence of various parameters on the inherent characteristics were discussed.The initial seismic response of the non-isolated tank model was analyzed.The finite element results are compared with the results of the code calculation and the Haroun-Housner method.The validity of the model was verified by comparing the results of the finite element method with the results of the code calculation and the classical method of seismic analysis.(2)Aiming at the structure of 1000m~3 storage tank,a kind of high damping isolation bearing was put forward.Combined with the common mechanical model and application of the isolation bearing,the calculation formula of the mechanical parameters of the high damping isolation support was given.The relationship between elastic modulus of bearing rubber and material constant was deduced.Based on the finite element software ADINA,the mechanical properties of the high damping isolation bearing and the free vibration characteristics of the high damping isolation tank model were analyzed.The results show that the natural vibration period of the storage tank system is increased by about 1.64s,and the vibration modes are mostly the translation of the superstructure,so the damping effect is better.(3)The shaking table test was carried out on the model of 1:5 scale storage tank.The results show that the acceleration and displacement of storage tank are magnified along the direction of tank height before isolation,and the amplification effect is significantly reduced after isolation,and the damping rate is more than 60%.(4)The dynamic responses of high damping rubber isolation and non-isolated tank models under near-and far-field horizontal unidirectional and horizontal-vertical earthquakes were compared and analyzed.The results show that the dynamic response of the non-isolated storage tank under the near-field action is much greater than that under the far-field action,and the high-damping rubber isolation bearing can effectively reduce the seismic response of the tank structure under the near-and far-field action,but the control effect on the sloshing wave height is not obvious.Amplification of response of non-isolated storage tanks under horizontal-vertical earthquakes;High damping rubber isolation energy effectively reduces horizontal response caused by fluid-solid coupling of vertical ground motion.(5)The finite element parameter analysis of high damping isolation tank and non isolated storage tank was carried out with ADINA.The effects of seismic intensity,height to diameter ratio,liquid level height,isolation period and damping ratio of isolation layer on dynamic response and damping effect of tank structure were studied.The reliability of the numerical model was further verified by comparing the finite element results with the shaking table test.