Finite Element Analysis of Structural Steel Elliptical Hollow Sections in Compression (No. R874)

Abstract

This paper presents a finite element investigation of the local buckling behaviour of the structural steel Elliptical Hollow Section (EHS) in compression. The theoretical elastic buckling load of an EHS is similar to that of a Circular Hollow Section (CHS) except that the diameter term, D, is replaced by D12/D2, representing the major and minor diameters of the ellipse. The overall aim is to examine whether an “equivalent CHS” can be used to model the local buckling of EHS when considering imperfections and non-linear material properties. The finite element program ABAQUS was used to examine the local buckling behaviour of EHS with a range of aspect ratios from 1:1 (CHS) to 10:1 to examine the transitional behaviour. Three types of analysis were considered. The first stage was elastic buckling with no material imperfection. The second stage considered inelastic material properties, followed by measured material properties. The final stage was to investigate how geometric imperfection affected the buckling modes. The results are benchmarked against experimental results. It was found that the use of an equivalent CHS was a reasonably good predictor of capacity of slender sections and the deformation capacity of compact sections. However, further benchmarking against experimental results is recommended.