Lateral-torsional buckling resistance of cold-formed high strength steel rectangular hollow beams

Hollow sections have been widely used for steel structures. Applications of High Strength Steel (HSS) on cold-formed hollow sections lead to thinner and lighter structures. This paper presents numerical investigations on the lateral-torsional buckling resistance of the cold-formed high strength steel rectangular hollow beam. Results from finite element analysis using Abaqus software are compared to calculations accroding to Eurocode 3. First, buckling analyses are carried out to investigate buckling behaviors of the rectangular hollow beams. In this step, elastic critical moments have been investigated and compared to calculations according to SN003. Buckling shapes have been also obtained in this step. Secondly, nonlinear analyses using Riks method have been performed. Buckling resistances of the beams with various thicknesses, various high strength materials S460, S650 and S960 have been compared to calculations according to EC 3. Further investigations on geometric imperfection sensitive have been carried out with different amplitudes L/1000, L/750, L/500 and L/250. EC 3. Buckling shapes have been also obtained in this step. Secondly, nonlinear analyses using Riks method have been performed. Buckling resistances of the beams with various thicknesses, various high strength materials S460, S650 and S960 have been compared to calculations according to EC 3. Further investigations on geometric imperfection sensitive have been carried out with different amplitudes L/1000, L/750, L/500 and L/250. 2 FINITE ELEmENT modELS 2.1 Geometry of models Rectangular hollow beams with end moments have been considered. Length (L) of the beam is 6000 mm. dimensions at center of the beam cross section is presented in Fig. 1. The height and width of cross section are 300 mm and 100 mm respectively. Radii at the corner is 25 mm. Various thicknesses (t) 6 mm, 8 mm, 10 mm, 12 mm, 14 mm have been taken into this study. Various lengths of beam have been used to construct a buckling curve of the rectangular hollow section.