Research On Static Behavior Of Pentagon Hollow Flange Beam

The Hollow Flange Beam is a unique cold-formed steel section developed in Australia for use as a flexural member. The HFB is manufactured from a single strip of high strength thin-wall steel by cold forming and electric resistance welding. Because of its section with two torsionally rigid closed triangular flanges and a comparatively flexible web, it is a type of high efficient cross section, and the HFB is widely used in light-weight steel structures in foreign countries. Recent years, our university presented a type of Pentagon Hollow Flange Beam (PHFB), and the earlier research has identified that it is more efficient than HFB under uniform bending, because of its wider cross section and greater flexural rigidity around its minor axis. This thesis presents a further research on PHFB so that we can draw some conclusions good for engineering application.The main contents are listed as follows:1. Finite element analytical model of PHFB under uniformly distributed loads is built up. Eigenvalue Buckling Analysis is performed, and the effects of the span length on the buckling modes of PHFB are analyzed.2. Nonlinear Buckling Analysis including geometry and material nonlinearity of PHFB under uniformly distributed loads is conducted. The load–displacement curve of PHFB is presented. The relative ultimate bearing capacity of PHFB with that of HFB is compared, then the difference between PHFB under uniformly distributed loads and PHFB under uniform bending is analyzed.3. The behavior of PHFB with web stiffeners is investigated. The effects on buckling capacity of PHFB with two web stiffeners and on ultimate bearing capacity of PHFB with different numbers of stiffeners are analyzed.4. Parametric analysis on PHFB under uniformly distributed loads is made. The effects of main geometry's parameters to the buckling capacity are analyzed, and reasonable parameters of geometry are proposed. The static behavior of PHFB under combined compression and bending is tentatively explored. Buckling modes and buckling capacity of PHFB under concentric and eccentric load are analyzed.