Experimental evaluation of the material properties for finite element analysis of cold-formed steel sections

Experimental investigations to evaluate the mechanical properties, and the built in residual stresses of channel-shaped cold-roll-formed steel sections are reported in this paper. Tensile coupon tests were used to evaluate the mechanical properties at the flat zones and at the corner zones of the sections. Electrical resistance strain gauges with an 'Electrical Discharge Machining' cutting technique was used to establish the magnitudes, and the distributions of residual stresses. Based on the experimental results, analysis models for the stress-strain relationship, the variation of the yield strength, and the residual stresses across the section have been established. The proposed material models have been incorporated within a large deformation elasto-plastic shell finite element to form a model for cold-formed steel sections. The efficiency and the accuracy of the proposed material properties models, as applied to a finite element model has been evaluated against corresponding experimental results of cold-formed steel sections subjected to axial compressive loads.