Residual Stresses in Cold‐Formed Steel Members

Abstract

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.