Study On Stretch-Draw Tecchnology Of Prestress LNG Storage Tank

With the rapid growth of demand for liquefied natural gas (the following refers to as LNG), as well as the strategic reserve requirements for energy,there are more and more requirements for LNG reserving containers. Now, the most widely used in LNG storage tanks are pre-stressed structure. Reasonable calculation for pre-stressed LNG storage tank at a variety of load bearing internal force and deformation has become an urgent requirement for designers.The applications of China for the cylindrical pre-stressed LNG storage tank are becoming increasingly widespread, as it is current lack of detail and systematic theoretical analysis and research, especially, the research of tension process is little.The paper simulates dynamic analysis of the earthquake response,which points to the concrete wall of the 50000m3 prestressed LNG tanks.The main work is as follow:1.Applying to ANSYS finite element software, established finite element model which is suitable for the theory of classical shell of prestressed LNG tanks cylindrical of concrete wall. And selected a reasonable element to simulate the tanks of concrete entity unit and prestressed steel.2.The tension of the pre-stressed LNG tanks: we can get reference from the similar structures (circular pool, silo, coal bucker and etc), draw annular tendons firstly, and consider actual conditions of construction, labors, equipments and so on, draw in the different orders from up to down or from down to up, then draw the vertical pre-stressed steel;At artical aspect, we must do symmetric tension from two points, three, and four points. Using ANSYS finite element analysis software, we imitate the annular tension in quarter of the storage tank and the vertical tension in the whole.3. Through two units mutual coupling, using the equivalent cooling method to simulate the pre-stressed reinforcement effect inentity unit. Through internal force computation analysis to cylindrical wall model of pre-stressed LNG storage tank, get the change of wall in different tension sequence, stress and displacement. Concluded that this method is more suitable to the actual construction conditions, and get a safety, economic, reasonable drawing scheme. Providing the theoretical basis for practical engineering and numerical analysis.