Analysis of steel tank shell deformation and its impact on further utilisation

Abstract

Recent research in thin-walled structures and steel structures has demonstrated that, in addition to internal forces and membrane stresses of shells, initial deformation and imperfection components should also be considered when calculating design cases. This paper presents a numerical analysis of a steel water tank with an initial deformation of the shell, which is used in an industrial plant for technological purposes. The steel water tank is a typical type of thin-walled structure for which initial deformation may be important. In the numerical example, a round symmetrical steel tank 2.70 m high is analysed under two states: with an undeformed shell and a deformed shell. The complicated interaction between the initial deformation and the vertical and horizontal stresses is analysed in detail. While the initial deformation of the shell may sometimes reduce stresses, in most cases, it substantially increases the overall stresses of the analysed steel water tank shell, up to 820% (for stresses in the horizontal direction) and up to 3554% (for stresses in the vertical direction). This means that initial large deformation and imperfections effects may play an important role not only in the design of industrial structures like silos and tanks but also for very specific slim, thin-walled structural elements.