Comparison between Elastic and Inelastic Lateral Torsional Buckling Load on Circular Fixed Channel Section Arches under Transverse Point Load

Abstract

This paper presents a Finite Element Analysis (FEA) investigation on the elastic and inelastic prebuckling behaviour and Lateral-Torsional Buckling (LTB) loads on circular fixed ends arches of 6061-T6 aluminium alloy channel sections subjected to a transverse point load at the shear centre. The software package Abaqus was used to study a total of 110 arch models from three separate channel sections with an additional 16 arch models for validation. From the channel arches, 66 were developed at a constant length, while the remaining 44 arches were formed at constant slender ratios using 11 discrete included angles. The analytical and FEA prebuckling results showed good agreement, indicating that the FE models were reliable, efficient, and accurate. From this comparison, the elastic axial compressive forces were found to be higher than those of inelastic prebuckling ones and the opposite was true for the bending moments. For arches developed at constant span length, the maximum elastic LTB load overestimated the real LTB load by over 48 percent and decreases as the web to flange width ratio increases. Furthermore, the maximum elastic LTB load for arches developed constant slender ratio, ⁄ = 60 overestimated its inelastic counterpart by 38.8 percent. While at ⁄ = 90, the elastic LTB load overestimated its inelastic counterpart by only 14.1 percent. It was also found that as the slender ratio increased, the difference between the elastic and inelastic LTB loads drops and vice versa.