| Vertical cylindrical steel storage tanks can be used to store petroleum,liquefied natural gas and other energy sources,and are a typical thin-walled kind of structure,which may fail due to uneven foundation settlement or earthquakes,resulting in liquid storage leakage,economic losses,and casualties.Therefore,studies should be made on it to ensure the safe service of the storage tank.In this paper,a numerical analysis method for the seismic dynamic response of liquid storage tanks under uneven settlement was established to study the influence of uneven settlement on the seismic response of liquid storage tanks,and research on the strength of large fillet welds of liquid storage tanks under the action of uneven settlement and seismic loads was carried out.The main works and results are as follows:(1)Based on the two-way fluid-solid coupling technology,a time-history analysis method for seismic response of liquid storage tanks considering the tank-liquid coupling was established,and a numerical simulation analysis of the seismic dynamic response of a 4000m~3 fixed-roof liquid storage tank was carried out.First,wet modal analysis on the liquid storage tank with different liquid storage heights was performed to prepare for transient dynamic analysis.It was found that the natural frequency of the storage tank decreased as the liquid storage increased,and the natural frequency of the liquid sloshing mode was relatively lowest,and most easily to be motivated.An artificial seismic wave with a basic design acceleration of 0.2g was fitted for loading.The nonlinear dynamic time history analysis method of the liquid storage tank under the action of the horizontal seismic wave was introduced in detail,and the seismic response of the storage tank was analyzed.The results showed that the height of the liquid sloshing wave was smaller than the calculated value of the formula in the standard,and the lifted-up of the tank bottom,the stress and deformation of the tank wall were small,indicating that the loaded seismic wave had little influence on the liquid storage tank,which was relatively safe.Finally,the seismic time history analysis method was verified by wave height,which proved the reliability of the method.(2)Aiming at the liquid storage tank with the uneven settlement,a numerical simulation method of its dynamic response under the action of seismic load was established.Change the direction angle of the horizontal seismic wave and load them on the liquid storage tank under uneven settlement every 30°respectively to study the influence of the circumferential distribution of uneven settlement on the seismic response of the liquid storage tank.It was found that the maximum stress on the tank wall was mostly concentrated on the tank wall in the upwardly swelled area of the foundation,indicating that the upward swelling of the foundation had a greater weakening effect on the strength of the tank wall than the downward settlement.The influence of the liquid storage height in the tank on the liquid sloshing wave height and tank wall stress and deformation was analyzed.As the liquid storage height increased,the liquid sloshing wave height and tank wall stress gradually increased,while the tank wall deformation gradually decreased.(3)Based on the multi-unit hybrid modeling method,the strength analysis of the large fillet weld of the liquid storage tank under the action of uneven settlement and seismic load was carried out.A comparative study was carried out on the strength of large fillet welds of liquid storage tanks under the sole action of uneven settlement,under the sole action of seismic load,and under the action of uneven settlement and seismic load.Analyze the changes of Mises stress at the location where the maximum peak stress occurs over time during the earthquake action time.It was found that the variation range was relatively large,indicating that the stress of the large fillet weld was sensitive to changes in hydrodynamic pressure. |
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