Buckling behaviour of steel dome cap design under external pressure

Abstract

This study aims to numerically investigate the buckling behaviour of externally pressurised dome caps. Following the recommendations of the European Standard EN 1993-1-6, there was good agreement between the Finite Element (FE) model and the experimental results, with an average difference of less than 7 %. Several imperfection approaches, such as (i) single load indentation (SLI) and (ii) axisymmetric outward bulge (AOB), and (iii) eigenmode-affine (EM) were used to analyse the dome cap. The EM proved to be the worst imperfection for the externally pressurised dome cap, yet the SLI is an attractive technique for simulating realistic imperfections. The imperfection tolerance was designed according to EN 1993-1-6, and the SLI was used for the realistic-case imperfection. From parametric study, a plot of the upper and lower bound curves serves as a design recommendation, similar to the NASA SP-8032 guideline. Through a regression analysis, a first-cut estimation equation of the imperfect dome cap buckling load with reliability of R2 = 0.97. A case study of shell buckling design on pressurization damage to an oil storage tank's spherical shell partition and its stress assessment are evaluated. This study provides a practical solution for the evaluation of buckling of steel domes under external pressure.