Understanding the buckling behavior of cold‐formed steel members with slotted web by using cFEM

Abstract

In this paper the buckling of lipped channel cold-formed steel members with slotted web is discussed. These members typically have complicated buckling behaviour, since it is a combination of various types of buckling, such as lateral-torsional buckling, distortional buckling, plate buckling, web crippling, or shear buckling. Though it is practically desirable to separate the various buckling types, this cannot easily be done without a specific numerical tool. Such a tool is the constrained finite element method, which is perhaps the only method at the moment which can separate the behaviour modes, and which can be applied to a wide range of thin-walled problems including members with holes. Separation is primarily performed by geometrical criteria, but further separation is possible on the basis of the stress components. In this paper one beam problem is presented and discussed. Critical loads and corresponding buckled shapes are calculated by allowing various pure and combined deformation modes. The calculations prove the practical advantage of the constrained finite element method.