Doom-roof steel tanks under external explosion: Dynamic responses and anti-explosion measures

Abstract

Large-scale cylinder storage tank is a kind of typical thin shell space structure, which is widely used in the storage of petrochemical products such as LNG, LPG and so on. The dynamic responses and failure process for steel tank under external explosion shock wave are complex dynamic problems with strong instantaneity, strong non-linearity and strong coupling. In this paper, a coupled analysis model was developed for simulating the dynamic responses of tank under external ground explosion. Compared with experimental datas which were given in existing relevant studies, the validity for numerical model and accuracy for simulation results were verified. Dynamic response for typical cylindrical tank was obtained through coupled numerical simulation, and the influences of scaled distance and tank wall thickness were studied through parameter analysis. Based on the simplified model of explosion loading on tank, the difference of dynamic response between uncoupled model and coupled model was analyzed. The anti-explosion effect for different parameters of anti-explosion bands on tank under external explosion was finally compared. The results show that: 1) The lower two layers tank wall firstly appear inward concave deformation and local plastic state. With the shock wave propagating upward along tank wall, the concave deformation and plastic strain of the front surface of tank wall increase obviously, and the maximum deformation region moves up to the middle part of tank wall, while the maximum plastic region basically remains at the lower part of tank wall. 2) Both the changes of scaled distance and tank wall thickness have significant influences on the deformation and equivalent plastic strain for steel storage tank. The maximum equivalent plastic strain and fracture failure mode generally appears at the lower part of tank wall firstly. The increase of the tank wall thickness is an effective measure to reduce the deformation and plastic strain for tank, and strengthen the anti-explosion performance for tank. 3) Due to the obstacle effect of the anti-explosion bands, the maximum equivalent plastic strain region moves from the bottom part of tank wall to the middle and upper part of tank wall. The displacement and equivalent plastic strain for steel tank decrease with the increase of cross-section and spacing for anti-explosion bands, and the effect of the former (increase height only) is relatively better.