Seismic Response Analysis And Isolation Study Of Large LNG Storage Tanks

In recent years, the natural gas accounts for larger and larger proportion in theenergy system of our country, it is of an important strategic meaning for energydevelopment in China. It is usually kept in storage in LNG (Liquid Natural Gas)storage tanks as the form of ultra low temperature liquid.The leakage happening tothe LNG storage tanks because the earthquake will result in serious accident such ascasualties, loss of property and environment pollution, so the sduty in LNG storageseismic performance has huge theoretical and practical significance. So far, designcodes for LNG storage tanks in our country is imperfect, and the sduty in LNGstorage tanks always neglect the influence of many factors such as the interactinbetween the outer tank and inner tank, the coupling effect between the inner tankand the LNG fluid and the interaction between the cap and the piles, so the study isdefficult to have a real evaluation of the LNG storage tanks’ seismic performance.Based the aboved problems, this thesis establishs the elaborate finite element modelof160thousands cubic metres LNG storage tanks, and study the seismicperformance of LNG storage tanks, analysis the influence of the base isolation toLNG tanks seismic performance. The specific work is devided into four parts asfollows:Part1: According to the LNG storage tanks prototype in our country, establishthe LNG tanks model with the interaction between the inner and outer tank, fluidsloshing and coupling between kinds of factors.Part2: Accomplish the modal analys is of outer tank alone, inner tank alone,and whole LNG storage tank, and compare the results to that of standard calculationand the existing literature to verify the reliability of finite element model.Part3: According to the seismic fortification intensity of the LNG projectregion, analysis the seismic response of the LNG storage tanks under different kindsof earthquakes with different peak acceleration, analysis the liquid sloshing and thetanks bottom uplift, reveal the seismic failure mechanism of LNG storage tanks.Part4: Establish the LNG storage tanks finite element model with baseisolation, and analysis it’s seismic response, and compare to the structure responseof the tanks without isolation. Evaluate the impact of isolation to the LNG storagetanks.