Finite Element Analysis and Buckling Behaviour of I-shaped Beams with RHCFST Upper Flange

Abstract

In order to analyse the buckling behaviour of I-shaped beams with rectangular high-strength concrete-filled steel tubular (RHCFST) upper flange, a total of 7 simply-supported beams are designed with height-width ratio of upper flange and span as the main parameters in this paper. Based on ANSYS software, the finite element models are established, and the eigenvalue buckling analysis of seven simply-supported beams are carried out. The buckling loads of the composite beams can be obtained and the influence of height-width ratio of upper flange and span on eigenvalue buckling loads of each order of the beams can be studied. The results show that the buckling loads of each order of the beams can be significantly improved with the decrease of the height-width ratio of upper flange and span. Height-width ratio of upper flange and span have greater influence on high-order buckling load of beams. When the first-order buckling mode of the beam is analysed, overall flexural-torsional buckling occurs and the overall linear displacement and angular displacement reach the maximum at the mid-span position of the beam. It can be concluded that the displacement of the beam is mainly out-of-plane displacement in Z direction, and the rotation of the beam is mainly in X direction. It lays a foundation for further nonlinear buckling analysis of such composite beams.