Strength Comparison of Fixed Ended Square, Flat Oval and Circular Stub LDSS Columns

Abstract

Structural behaviors of fixed supported Lean Duplex Stainless Steel (LDSS) hollow stub columns of flat oval, circular and square cross-sections are presented on the basis of 54 models using finite element (FE) analyses. In order to assess the relative performance of various cross-sections, the material consumption has been made equal (i.e. equal perimeter). It is observed that for thinner sections (t ≤ 10 mm), the influence of local imperfection on decreasing ultimate load (Pu) is in the order square > flat oval > circular cross sections. For t < 10 mm an increase in Pu is seen in the order square < flat oval < circular cross sections, with no significant change in Pu for higher thicknesses. With increase in cross-sectional perimeter of ~24 % from ~828 mm, the percentage change in Pu of thin section (t = 3 mm), are ~ +20, −20, −2.5 % for circular, square and flat oval (l/r i.e., ratio of flat length to curvature radius = 1 to 2; r = 100 mm), while for thicker sections (t = 25 mm) it is ~ +23 % for all sections. The deformation corresponding to Pu, showed relatively similar values for thin section as compared to thicker sections (t ≥ 15 mm) wherein the square section showed greater deformation capacity whereas both circular and flat oval section showed similar values.