Simplified Analysis Based On Shaking Table Test Of Storage Tank And Study Of Liquid Sway And Tank Wall Pressure

Storage tanks are often used to store some fuels and combustible substances,and large unanchored tanks are important equipment for storing these substances.Therefore,the occurrence of seismic isolation in the area where the tanks are installed can cause many direct losses and secondary disasters.Therefore,it is important to conduct research related to seismic isolation of storage tanks.Although many scholars have conducted research on seismically isolated storage tanks,there are still deficiencies in some aspects.For this reason,this paper presents a shaking table test of seismically isolated storage tanks,a study of a simplified method for calculating the basal shear of seismically isolated storage tanks,a shaking analysis of the liquid in seismically isolated storage tanks,and the stress distribution law of the tank walls.The research and related conclusions of this paper are as follows:The prototype tank volume of 1000 m3 was studied,and the test model tank for shaking table test was designed according to the prototype tank: model tank ratio of 5:1.(1)The comparative analysis of the basal shear of the seismically isolated tank and the single-mass model was analyzed,and the results showed that the basal shear of the seismically isolated tank was related to the basal shear of the equal-mass block.The test shows that the maximum value of the wall stress appears below the middle of the tank.The test results of the basal shear of the tank and the basal shear of the equal-mass block obtained from the test were used to propose a single-mass point mechanical model of the seismically isolated storage tank,which was improved on the basis of the existing theory;the seismically isolated single-mass point program was written using MATLAB software.Two methods for calculating the basal shear force of seismically isolated storage tanks,the mass correction coefficient method and the force correction coefficient method,are proposed,using the seismic site category as the classification criterion.Through extensive analysis and calculation,it is shown that the values of the correction coefficients of the two methods are basically the same,and the errors of the single-mass point calculation model and the current mature three-mass point calculation model are controlled at about 10%.The finite element software ADINA was used to establish the test model of the seismic isolation tank and analyze the relationship between the shaking wave height of the liquid in the isolation tank and the excellent frequency of ground vibration;the results show that the shaking of the liquid in the isolation tank is a long-period motion,the shaking frequency of the liquid is 0.628 Hz,and the peak value of the shaking wave of the liquid in the tank is the largest when the excellent frequency of ground vibration is 0.2Hz.The wall stress analysis of the seismically isolated storage tank was analyzed with the prototype tank used for the test,and the distribution law of the wall stress was studied at different seismic intensities,different seismic frequencies and different liquid level heights.The results show that: the wall stress reaches its maximum value when the seismic frequency is 0.5 Hz;the distribution of the wall stress has the same trend at different seismic intensities,and the wall stress is relatively smaller at low intensities;the size of the stress on the tank wall and the height of the liquid inside the tank,the greater the height of the liquid inside the tank wall stress,and vice versa,the smaller the stress on the tank wall.Therefore,the analysis is proposed to divide the liquid inside the tank into two parts for correlation,i.e.,the tank is composed of the outer tank and the inner tank,and the diameter of the inner tank is taken to be 50%,60% and 70% of the outer tank diameter;the distribution law of stress and liquid shaking wave height of the outer tank wall is analyzed at different inner tank diameters,and the results show that: when the inner tank diameter is 60% of the outer tank diameter,the stress and shaking wave height of the outer tank can be effectively,it can effectively reduce the stress and shaking wave height of the outer tank of the vibration isolation tank.