Finite element modelling of cold-formed steel beams under local buckling or combined local/distortional buckling

• Published in: Thin-walled structures 2011-12, Vol.49 (12), p.1554-1562
• Main Authors: Haidarali, Mohammad Reza, Nethercot, David A.
• Format: Article
• Language: English
• Subjects: Beams (structural); Buckling; Cold-formed steel; Distortion; Distortional buckling; Exact sciences and technology; Finite element analysis; Finite element method; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Local buckling; Mathematical analysis; Mathematical models; Nonlinearity; Physics; Solid mechanics; Steel structures; Structural and continuum mechanics; Structural steels; Ultimate strength
• ISSN: 0263-8231; 1879-3223
• DOI: 10.1016/j.tws.2011.08.003

The finite element (FE) method is capable of solving the complex interactive buckling of cold-formed steel beams allowing for all important governing features such as geometrical imperfections, material nonlinearity, postbuckling, etc.; this is unlikely to be achieved by analytical methods. In this paper, two series of finite element models for buckling behaviour of laterally-restrained cold-formed steel Z-section beams have been developed with special reference to material and geometrical nonlinearities: one to allow for the possibility of combined local/distortional buckling and the other to allow for local buckling only. Four-point bending tests carried out by previous researchers have been used to verify the FE models. A simplified configuration of the test setup has been modelled in ABAQUS. In the local buckling FE models, distortional buckling has been restricted in the member using translational springs applied to the lip/flange corner of the beam. Predictions of load carrying capacity and deformed shapes exhibit excellent agreement with both the results from the more extensive models and laboratory tests. Further papers will exploit the developed FE models to investigate the different forms of buckling that occur in laterally-restrained cold-formed steel beams i.e. local, distortional and combined local/distortional. ► Presents an FE model to simulate combined local/distortional buckling of thin-walled beams. ► Presents an FE model to simulate pure local buckling of thin-walled beams. ► Analyses clearly match existing laboratory test data. ► Adapts models so that effect of local and distortional buckling may be studied separately. ► Models are suitable for parametric studies due to their computational efficiency.