Građevinski Materijali i Konstrukcije (Jan 2019)
Flexural buckling of hot-finished and cold-formed elliptical hollow section columns: Numerical comparative analysis
Abstract
Even though structural elements of the elliptical hollow section (EHS) have been introduced to the construction market in the past years, the rules for their design were only partially introduced into the suitable codified procedures. The aim of this paper is to present a comparative numerical analysis of behaviour of coldformed and hot-finished EHS columns exposed to flexural buckling under pure axial compression. Pinended columns of a various slenderness without lateral restrains and with incorporated geometrical imperfections are analysed. Material nonlinear behaviour is included through published experimental tensile test results, conducted in previous researches. In addition, numerical simulations of stub column behaviour are performed in order to obtain a cross-section compressive resistance. Results of the finite element analysis are compared to the design criteria defined in the draft version of Eurocode EN 1993-1-1:2015 and in North American specification for cold-formed member design AISI-S100. It is observed that North American standard provides more accurate predictions of both a crosssection resistance and a buckling column resistance. Equivalent diameter method described in Eurocode 3 led to more conservative results. According to the obtained numerical results, similar buckling behaviour is observed for both hot-finished and cold-formed columns of higher slenderness, while in the lower slenderness region, coldformed compressed members tend to lower buckling curves. Underestimation of a column buckling resistance according to Eurocode regulations is noticed for coldformed members of a higher slenderness.
