Three-dimensional Dynamic Response Analysis Of The Structure Of Natural Gas Tank Under The Action Of Near-field Earthquake

In modern industry,large liquefied natural gas(LNG)storage tank is applicated widely,and most of them are built forcely in the earthquake area by the restriction of the various social conditions and environmental factors.Once the storage tank is broken,that is easy to happen the damage under the earthquake,and is likely to lead to tank damage,fire and other secondary disaster,and then,resulting in severe economic losses and casualties.Therefore,it is urgent to carry out the research on LNG storage tanks under the near-field earthquakes.Most seismic and isolation studies show that horizontal and unidirectional seismic damage is relatively large.Otherwise,vertical seismic action is often overlooked.whence,this paper will use the finite element analysis method is study the dynamic response of the structural LNG storage tank with lead core rubber vibration isolation pad under the near-field three dimensional seismic action.Based on this,the finite element model of ABAQUS of 1000m3 reservoir was established in this paper and the seismic response of the reservoir with isolation and no isolation was analyzed in the near and far-field triaxial earthquake.At the same time,the finite element model and test model are established to verify the validity and reliability of the finite element model.The conclusions are as follows:(1)Under the effect of three seismic waves in the near and far fields,making the comparative analysis of the base shear,the overturning moment and the sloshing wave height of the tank with and without isolation,the base shear and the overturning moment of the base isolation tank are significantly reduced,and the shock absorption effect isobvious.There is no significant difference between the three near-field and the far field seismic waves,and the level of the sloshing wave height is not obviously reduced,and even the sloshing phenomenon of the liquid surface appears.(2)Under the action of three to different earthquakes,the acceleration of the horizontal to non isolation tank is increased along the bottom of the tank first,and the acceleration is maximum in the middle of the tank structure.With the close to the liquid surface,the acceleration begins to decrease,and the acceleration of the tank wall decreases rapidly in the upper part of the liquid surface.The acceleration of tank varies little along the height of tank wall,and the isolation effect is very good after isolation.Under the action of seismic wave,the acceleration has amplification effect along the direction of the tank wall relative to the input acceleration,and the acceleration of the tank wall increases with the height of the tank wall.When the shock is isolated,the tank wall has a decrease effect relative to the input seismic wave,and the acceleration along the tank wall height of the tank is nearly vertical.The difference between Near-Field Seismic Wave and far-field seismic wave is not very large,which shows that the isolation effect is very good.For the displacement response,the horizontal direction of the horizontal non isolation tank varies linearly along the height of the tank wall,and the displacement response of the non isolated tank wall from the bottom to the top of the tank is very large.When the isolation is applied,the displacement varies little along the height of the tank,and the displacement response is almost the same.Vertical,isolated and non isolated bearing tanks all move vertically up and down the whole rigid body movement,and the vertical displacement of isolation is smaller than that of non isolated ones.The vertical displacement of the far field seismic wave is much smaller than that of the near field seismic wave,so the horizontal direction has good isolation effect to both the far field seismic wave and the near field seismic wave.In the vertical,the far field seismic wave of the isolation effect is better than the near field seismic wave.(3)Stress analysis of tank wall,including equivalent stress,average section stress of tank wall,ring stress and axial stress.In non isolation,the maximum stress location is at the bottom of the tank,and decreases along the height of the storage tank.In isolation,at the same,the maximum stress tank wall is the distance from the bottom ofthe tank,and decreases along the height of the storage tank.The effect of isolation and non isolation is not very significant from the effect of isolation.The equivalent stress,the average interfacial stress and the circumferential stress on the tank wall are better than those under the near-field seismic wave.The distinction between the isolation of the axial stress under the action of far-field seismic wave and the near-field seismic wave is not very obvious.