A comparative study on the effects of boundary constraints on electromagnetic sheet forming

This paper investigates the effect of boundary constraints on the plastic deformation behavior of a ∅458 circular sheet metal in an electromagnetic forming process. Both experiments and simulations were conducted on a flat spiral coil system. In the experiments, two different boundary conditions were imposed on the workpiece flange by utilizing a blank holder with and without a draw bead to control the draw-in of the flange. Both the final profile and thickness distribution of the workpiece are sensitive to the boundary constraint, due to the varied draw-in material flow. Furthermore, according to the morphology characteristic of the deformation profile, three typical deformation stages can be recognized, where the thickness reduction at the sheet center only occurs in the first and third stages. This work provides a better understanding of the deformation behavior in the electromagnetic sheet-forming process under varied boundary constraints, which is fundamental for the further development of this process.