IMPROVING DESIGN OF NATURAL DRAUGHT COOLING TOWERS AGAINST BUCKLING FAILURE

Abstract

In this paper the buckling of hyperbolic cooling towers containing different forms of stiffening is presented. Stiffeners are sufficiently close in spacing that the stiffened shell may be modelled as a shell having homogeneous and orthotropic material properties.

Analysis is completed by means of a finite element numerical method. The numerical results for critical loads and modes of the cooling towers with different stiffening types are described and compared with those of an equivalent weight smooth tower. A systematic examination of the contribution to strain energy is shown to elucidate the physical behaviour and demonstrate how the various stiffness components of shell and stiffeners affect the critical load spectra and the associated modes. Not only does this analysis provide a clear explanation of how the addition of different stiffening types affect the critical load spectra, but also suggests an effective design procedure for optimizing material efficiency.

KEY WORDS:

• Stiffened shell
• cooling tower
• buckling
• design