Deformation Analysis of Side-Wall Curl in the Sheet-Metal Forming of Flanged Channels

The side-wall curl occurring in the sheet-metal forming process of a flanged channel was examined by a proposed theoretical model in the present study. Since the side-wall curl results from the elastic recovery of the plastically deformed sheet metal, the stress distribution produced in the forming process is examined. In the theoretical model, the deformation of the sheet metal drawn over the die shoulder is assumed to be subjected to bending, sliding, and unbending processes, in which only the sliding process contributes to the frictional force. The governing equations derived from the theoretical model were solved by a numerical procedure, and the stress distribution through the sheet thickness was obtained to calculate the side-wall curl. The proposed model was validated by the finite element simulations both quantitatively and qualitatively, and by the experimental data obtained from the published literature qualitatively. By using the proposed model, the effects of the process parameters on the side-wall curl were investigated.