Structural behaviour of fixed ended stocky Lean Duplex Stainless Steel (LDSS) flat oval hollow column under axial compression

This paper presents finite element analyses of Lean Duplex Stainless Steel (LDSS) flat oval hollow slender columns of stocky cross sections, by varying geometrical parameters like flat element length (lf), radius of the curve element (r), distance between the flat elements (w), length/height of the columns (l), and thickness (t), using Abaqus. Based on the FE analyses, structural performance of the columns under axial compression were assessed, with attention towards, load capacity and deformation modes. Based on the parametric study, failure or deformation mechanisms have been identified depending upon ultimate and post ultimate structural behaviour viz., 1) Yield to yield with local bucking (λ¯<0.32, 2) Yield to yield with flexural buckling (0.32≤λ¯≤1.0), and 3) Flexural to flexural buckling (λ¯>1.0). It is seen that semi-circular curve section (r/w=0.5) showed the highest load capacity, with Pu remaining almost flat for r/w≥1.0. Load capacity, in general increases with increase in lf, w, and t. Pu decreases with l, although, the rate of decrease is relatively less sensitive to variations in lf and r; however, it is quite sensitive to variation in w. All the compared design codes, method and their modified versions are reliable and applicable, with βo value of 3.28, 3.52, 3.90 for EN-1993-1-4 (2015), AS/NZS 4673 (2001) and DSM (NAS [38]); and 3.38, 3.50 for modified AS/NZS and modified DSM (Huang and Young [9]) respectively.