FEM analysis of the buckling behaviour of thin-walled CFS columns. Part II-mono symmetric (R) and double symmetric built-up box cross-sections

Abstract

One of the main advantages of thin-walled CFS profiles is the "freedom" the designer has to conceive a cross-section shape tailored for the structural application. Consequently, different cross-sections shapes have been developed and may be found in the market. Furthermore, the combination of thin-walled CFS profiles, in the form of built-up cross-section members, further increases the range of available options. On the other hand, this diversity of solutions brings a challenge to the designer, as for some uncommon cross-section shapes, the mechanical behavior is not entirely known and therefore not covered in the design codes. Hence, in the present paper, the second part of a numerical study on the subject is presented. Columns consisting of the monosymmetric built-up box cross-section (R-section) and doubly symmetric built-up box cross-section (2R-section), comprising lipped and plain channels are investigated by means of FEM. The numerical models were developed and calibrated using experimental results on thin-walled CFS columns using these cross-section shapes. Upon validation, a parametric analysis is performed, to further assess the influence of different parameters, such as steel thickness, column length, boundary conditions and connection spacing.