RESIDUAL-STRESSES IN COLD-FORMED STEEL MEMBERS

An extensive experimental investigation of the residual stresses in cold-formed steel members is presented The electrical discharge machining (EDM) technique is used to cut coupons for residual stress measurement As compared to the conventional saw-cutting method the EDM technique greatly reduces the external disturbance during the machining of a thin-walled section caused by heating clamping and vibration The experimental results provide a further understanding of the magnitude and distribution of the residual stresses in cold-formed steel sections which are found to be quite different from the residual stresses in hot-rolled steel shapes Based on the experimental findings an idealized distribution pattern of the residual stresses in a cold-formed channel section is outlined Finally the yielding propagation in an axially compressed cold-formed steel section is described and an equation for predicting the extent of yielding is derived. © ASCE.