Fluid-solid Coupling Simulation Analysis Of Liquid-storsge Tank Under Earthquake Load

With the rapid development of the economy,oil is increasingly important as a non-renewable energy source.From the perspective of national oil resources adequacy,China is accelerating the development of oil reserves,and liquid storage tanks have become the most important oil storage tools.As the most common liquid storage container,vertical liquid storage tanks have been widely used,and the demand is increasing.In recent years,there has been a trend toward large-scale and floating type.Once the reservoir is damaged by the earthquake,it will not only cause economic losses,but also produce a very serious secondary disaster.Especially in a country with frequent earthquakes in China,it is even more necessary to conduct independent and targeted analysis of large-scale liquid storage tanks.In this paper,the response of the vertical liquid storage tank under seismic load is simulated and analyzed.The tool used is the general finite element ANSYS Workbench software.In the calculation,factors such as geometric nonlinearity,liquid-solid coupling,and large liquid sloshing are fully considered.The main contents include:1?Considering the variation of the pressure distribution of the tank wall and the influence of the deformation of the tank wall,the normal stress and strain in the tank wall are non-uniformly distributed,and only the shell element is used to calculate the deformation of the tank wall,which will cause certain errors.In order to determine the error range,for the small tank model,the liquid storage tank is meshed by the three-dimensional solid element and the shell unit respectively,and the simulation analysis is carried out under the same liquid conditions and seismic response,and important results such as stress and deformation are performed.The comparison.The results show that the stresses and deformations calculated by the two elements are basically the same in the value of the most value,and the distribution of results is slightly different in the extreme value region,and the difference is obvious in some special regions.It can be seen from the analysis of the overall comparison results that there is no qualitative difference between the results of the two analysis units,and the results calculated by the shell unit are within an acceptable range.2?The physical unit and the shell unit in the ANSYS Workbench software are low-order units without intermediate nodes,and only nodes exist at corner points and boundary points.When it is used to calculate the fluid-solid coupling problem of a large cylindrical shell or a multi-layer variable thickness shell,it is very difficult to converge the results due to the influence of nonlinear geometry and reduction integral.Considering the existence of the reinforcing ring on the tank body,the overall deformation of the tank body is very small relative to the volume of the tank body,and the liquid pressure in the tank body is not affected by the deformation of the tank body.The tank body is first regarded asa rigid body,and the liquid pressure in the tank body is obtained.The change in seismic load is applied to the tank as a load and the response of the reservoir under seismic loading is calculated.In order to determine the error range of the method,the response of the small tank model under seismic loading was calculated by the above method and the bidirectional fluid-solid coupling method.The results show that the deformation of the tank near the opening calculated by the two-way fluid-solid coupling is affected by the deformation of the tank.The maximum value is larger and the deformation distribution is more uneven.The results at the bottom of the tank are very close,and the stress strain is the same.3.For large-scale actual liquid storage tanks,the response of this method is obtained by using the method of this paper.By analyzing the liquid level of the tank and the deformation,stress,strain and acceleration of the tank,the dangerous area and maximum deformation of the tank under the seismic load were found,which provided the basis for the tank design.