Coupling Response Analysis Of Stress Field And Temperature Field For 160000 M~3 LNG Storage Tank

For the LNG tank, the cryogenic environment caused by the leakage of inner tank and the high temperature environment caused by the fire will cause the tank wall to generate a large temperature gradient, and make the temperature stress uneven,weaken the properties of the material, even destroy the tank. Therefore, it is very necessary to analyze the thermal response of concrete tanks under various conditions, and obtain its stress mechanism.Based on the ANSYS/Workbench, a finite element model is established for the actual subject. A thermal structural coupling analysis was carried out under normal operating condition, the leakage of the inner tank conditions and the near fire conditions.Conclusions are as followed:1、The paper set up the 2-D finite model of the LNG tank including the dome,concrete wall, insulation layer and simulated the distribution of the temperature for the tank when it works well in summer and winter. The results shows: the insulation material and the concrete ring beam on the edge of the platform are in adverse temperature conditions. It is necessary to adopt the material with better low temperature performance or take appropriate construction measures; the thermal corner protection structure play an important role to the position where the external wall and the bearing platform contact.2、Based on the existing model, and considering the reinforced bar and steel strand,the paper simulated the situation of thermal field when the LNG leaks. Then the data of the temperature field are introduced into the model for the analysis of the stress. The results shows: a large thermal gradient exist inside the concrete wall between the thermal corner protection layer and the liquid level of the leaking. While ,it brings little influence on the other parts. The deformation and the stress of the wall and the reinforced, steel strand are larger in the middle of the members in vertical.3、Based on the existing model, the paper simulated the thermal-structure coupling response of the LNG tank with other loads under the fire by the way of applying the heat flux on the surface of the wall, according to the codes and standards. The results shows:the temperature of the wall’s lateral side changed a lot compared with the inner side. The stress of the reinforced and the stranded wire remained along the vertical direction and the both of the peak are lower than the respective yield strength. The height of the compression area also remained along the vertical direction depart from the two ends of the wall. The minimum of the height meet the requirement of the standard. The deformation of the wall, reinforced and stranded wire appeared linear growth with the vertical above the pile cap.