Buckling and classification of high-strength steel CHS tubular members under axial compression and bending

Abstract

EN 1993-1-1 provisions classify high-strength steel CHS members with relatively low values of D/t ratio as Class 3 or 4, so that their strength is based on elastic behavior only, neglecting their capability of sustaining inelastic deformation before a maximum resistance is reached. To investigate the applicability of the above classification, a special-purpose numerical technique is employed to examine the resistance against local buckling of high-strength steel seamless tubular members with significant thickness, that exhibit local buckling in the plastic regime under axial compression and bending. The numerical technique employs large inelastic strains, accounts for the presence of initial imperfections/residual stresses, and is capable of describing deformation and buckling of tubular cross-sections well beyond yielding of the steel material. Imperfections and residual stresses from real measurements are used. Numerical results are presented in terms of both the ultimate load and the deformation capacity of typical cross-sections, and are compared with available experimental data. The results aim at evaluating the applicability of EN 1993-1-1 for cross-sectional classification of high-strength steel CHS seamless tubular members. © 2012 Taylor & Francis Group, London.