Wind-induced Response And Buckling Analysis Of Large Floating-roof Steel Tanks

As a kind of large storage structure,steel tanks are widely used in many areas of production life,especially in agriculture,industrial and oil plants,with the advantages of small area,large storage,fast building speed and less building materials.Because of the high diameter-thickness ratios and low aspect ratios,tanks are typical wind sensitive buildings.When subjected to strong winds,the steel tanks may buck in a short period of time or be destroyed by long-term energy accumulation.Therefore,it is of great practical significance to study the wind-induced response and buckling of large steel tank structures.In this paper,based on wind tunnel tests,the wind-induced response under mean and fluctuating wind loads and buckling under mean wind loads of three kinds of tanks with different aspect ratios are analyzed by using finite element software ANSYS.The main work includes the following several aspects:1)Based on the parameters and wind loads of a 100,000 m3 steel tank in the existing reference,the finite element model and loading are established,and the eigenvalue buckling analysis is carried out to obtain the first two buckling eigenvalues and buckling modes.Compared with the results in this reference,the results show that the difference of buckling eigenvalues is 4.2%,and the buckling modes are identical,which verifies the correctness of the research methods in this paper and establishes foundation to the subsequent analysis.2)Performing modal analysis of steel storage.The results indicates that the smaller the aspect ratio is,the longer the natural vibration period is;the smaller stiffness is,and the more sensitive the tank is to wind load.Carrying out dynamic response analysis of three tanks with different low aspect ratios by time domain analysis method under fluctuating wind loads,and comparing the results with that obtained under mean wind loads.The results show that the influence of fluctuating wind on tanks can not be neglected.The smaller the aspect ratio is,the more sensitive tanks are to the fluctuating wind load.Besides,the Mises stress and displacements in the windward region and the Mises stress in different heights increases as the aspect ratio decreases.3)Using the eigenvalue method and the arc length method,the buckling analysis of three large open storage tanks with different height-diameter ratios and floating roof tanks with different liquid level heights under mean wind is performed to obtain their buckling modes and critical buckling load factor.The results show that the buckling deformation mainly occurs in the windward region,where the buckling range increases as the aspect ratio decrease in general.It can also be seen that the stockier and thicker the tank is,the more sensitive it is to the initial imperfection in general.The different height of liquid level in tanks has a significant effect on distribution of wind load on the inside and outside tank walls.For full-filled liquid level,the wind buckling loads of all tanks increase greatly.