Finite Element Analysis Of Large Vertical Oil Tank Based On Contact Simulation Of The Interaction Between Tank Bottom Plate And Foundation

With the rapid development of petrochemical industry and in the light of the increasingly importance of energy security, a great number of large-scale oil storage tanks have been built worldwide. The large unanchored oil storage tank is the key equipment of the national strategic oil storage reservoir. Any failure of these tanks will be a catastrophe. Therefore, it is very important to conduct research on the safety assessments of these tanks. In this thesis analysis on the strength and deformation of the 5×10~4m~3 oil tanks have been conducted by the finite element numerical simulation. Following are the main research contents and results.With the aid of ANSYS software, the 2D axisymmetric and 3D solid FEA (Finite Element Analysis) model of large vertical oil tank was constructed. Contact elements were used to simulate the interaction between tank bottom plate and its foundation. Several types of element such as Solid95, Solidl85, Plane183, Targe169, Conta172, Targe170 and Conta174 were adopted to build the model. With the help of APDL (ANSYS Parametric Design Language), the FEA model was of parametric function.In the 2D axisymmetric FEA, through intensive analysis on the case of tank dead load and hydrostatic pressure, the stress strength and its distribution at the tank parts were obtained. It was found that the maximum stress intensity appeared in the connection between tank bottom and inside of grand welded joint. The maximum hoop stress was located at the middle and lower part of the tank wall and the axial change of hoop stress was no longer simply proportional to the hydrostatic pressure. In the whole sand filling area, the amount of settlement of the foundation is basically the same. The largest settlement gradient took place in the edge area of concrete foundation, producing large radial and hoop stresses in the corresponding area of bottom plate.For the 3D finite element model which considered the combination of dead load, hydrostatic pressure and wind load, results showed that wind load has nearly no impact on the settlement of the foundation, but has considerable influence on the strength of the grand welded joint between tank wall and the edge of the tank bottom.