Nonlinear Finite Element Analysis to Evaluate Lateral Torsional Buckling Moment of Elliptical Cellular Steel Beams

In evaluation the lateral torsional buckling moment of Elliptical Cellular beams, it cannot be directly accurately calculated because the sectional properties of the Elliptical Cellular beam are not constant along the beam length. Consideration of sectional properties at web-post section will certainly affect to unconservative result, and the consideration the sectional properties at web-opening section is also unreal and unduly conservative design. Therefore, the main objective of this paper is to present the guideline to evaluate the lateral torsional buckling moment of Elliptical Cellular beam for conservative result and more precisely. The study has been performed throughout finite element analysis in both elastic and inelastic buckling behavior subject of equal beam-ends moment. More than 15 sections, 120 of beam models were simulated and analyzed with verified finite element modelling by using shell element. The results of this study show that the most of beam has behavior in elastic buckling range, calculation the lateral torsional buckling moment of Elliptical Cellular beam with the original equation given in AISC standard with using the sectional properties at web-post section is given unsafe result about 5% in elastic range and up to 20% in inelastic and plastic range. Evaluation the lateral torsional buckling moment by use the reduction factor, R_ECB, that proposed from this study has yielded the conservative result and has more precisely, more economically and less distribution of the result than the evaluation that using sectional properties at web-opening section.