BEHAVIOR RESEARCH OF TWO NEW KINDS OF COLD-FORMED FLANGE-CLOSED SECTION BEND MEMBERS

Hollow flange beam(HFB) has particular cross section with two torsionally rigid closed triangular flanges and a comparatively flexible web,it is a type of high efficient cross section mainly used as flexural members.Based on the HFB section,it is put forward that two new kinds of cold-formed flange-closed welding sections named HF1 and HF2 through changing the component of section and section parameters of HFB.It is also presented a finite element analytical model suitable for non-linear analysis of HFB flexural members.The model includes all significant effects that may influence the ultimate capacity of such members,including material inelasticity,local buckling,member instability,web distortion,and geometric imperfections.On the base of precise finite element model,nonlinear finite element method is adopted to study the new sections' buckling modes,relative deflection,moment-curvature curves,and ultimate capacity.The static behaviors of the two kinds of sections are analyzed completely.It can be concluded that the new sections have the well characteristic of high rigidity,high ultimate capacity,local buckling of the sections always hard to occur,and can go deep into the experiment study as to be used in the practical engineering.