Distortional buckling of a CFS channel section with and without stiffened flanges

Cold-formed steel (CFS) sections are commonly applied to modern engineering structures, such as roof truss, purlin and industrial goods rack. This study proposes an analytical model to investigate the distortional buckling behavior of CFS-lipped channel sections considering two load scenarios (i.e., axial compression and pure bending). The formulae and analytical solution for calculating the distortional buckling critical stress of CFS channel sections are derived on the basis of the total potential energy principle. The proposed model is extended to the channel section columns and beams with a stiffened flange. CUFSM and generalized beam theory (GBT) are used to conduct numerous channel section columns and beams to validate the proposed method. Results obtained from the proposed model are compared with those calculated using GBT and/or finite-strip code CUFSM. These numerical results are consistent with the model calculations for channel section with and without stiffeners.