Distortional Buckling Of Perforated Cold-form Steel Channel-section Beams With Circular Holes In Web

Thin-walled,perforated cold-formed steel(PCFS)sections are constantly utilized in civil engineering because of its extensive advantages while the distortional buckling behavior of PCFS sections with respect to the capacity of members is not negligible.This paper presents the detailed investigations on the distortional buckling of perforated cold-formed steel channel-section beams with circular holes in web.The existing work on the distortional buckling of CFS channel sections includes the EN1993-1-3 distortional buckling model,Hancock distortional buckling model,Zhu-Li distortional buckling model,as well as numerical simulation including generalized beam theory,finite strip method and finite element method.Besides,the load bearing capacity is performed by finite width,direct strength method,Strength reduction method.In this paper,the distortional buckling of PCFS channel-section beams with circular holes in web is investigated by using the commercial software ABAQUS to examine the influence of the web openings on the critical loads.Similar distortional buckling curves are obtained from members with holes of variety sizes.The critical stress of distortional buckling of PCFS channel-section beam with circular holes in web decreases with increased hole size.Finite strip method is used for the buckling analysis of CFS members,verifying the validity of the finite element results.According to the EN1993-1-3 distortional buckling model,a formulation is proposed for the prediction of critical stress and critical moment of distortional buckling of PCFS channel-section beams with circular holes in web by reducing the energy of the web and calculatingthe spring stiffness ?.Finally,the critical stress and critical moment of local buckling and the node corner bearing bending was examined using finite element method.The reduction factor of angular stiffness k? is obtained by comparing with CFS members.Critical stress and critical moment of distortional buckling of PCFS channel-section beams with circular holes in web are determined using Hancock method.