A finite-element analysis of electromagnetic sheet metal expansion process

Sheet metal working by a flat spiral coil, a typical way of electromagnetic forming, has been extensively applied in the practical production. Based on the equivalent electric circuit method for analyzing the discharging process and the numerical model of magnetic pressure, an analysis of the effects of the force-energy parameters on the forming process in sheet metal expansion was made by the dynamic incremental non-linear elastoplastic finite-element method. The expansion height varies with the force-energy parameters of the electromagnetic forming system by experimental analysis, but the deforming speed becomes larger and the forming time shortens as the voltage or capacitance increases, which is just the reversal of the inductance. The experimental results showed that the scheme of the present analysis is valid for the prediction of the final shape in electromagnetic forming of flat workpiece. However, in order to obtain a more realistic description of the dynamic deformation fields, some improvement should be made in air damping model.