Analysis of contact buckling in built-up cold-formed steel beams assembled by laser welding

To investigate the effects of contact interactions on local buckling of a built-up cold-formed steel member assembled by laser welding a finite element model was developed. The numerical model was validated against the experimental results of a four point bending test on a full scale specimen. A good agreement with test data was observed both in terms of ultimate bending strength and deformed shape at collapse. The calibrated finite element model was used to estimate the effects on buckling resistance of contact forces between the parts of the beam by varying the connection spacing on the flanges. As a main result, it was shown that contact interactions influence remarkably the ultimate strength of the beam and that their effects decrease with decreasing spacing of connections.