Parametric Study of the Design Variables Involved in the EMF Process of Sheet Metal

This study carries out a numerical parametric analysis on some key variables of an electromagnetic forming (EMF) system designed for free bulging of circular metal sheets, aiming a high and adequate distribution of electromagnetic pressure produced by the EMF system using a spiral actuator coil with a single-layer. The proposed methodology considers fully coupled electric-magnetic problems but uncoupled with the mechanical phenomenon, and solves the equations related to the coupled electrical circuits, identifying the influence of their parameters on the EMF process. Further, a calculation method is presented for the time-dependent electromagnetic pressure intensities and distributions along the radial direction, regarding their dependency in relation to the EMF system parameters. The research methodology is suitable to aid in the EMF systems design, evidencing the parametric influences, considering the pulse unit, and the EMF system geometry. The numerical results show that there exists an optimum time for the maximum electromagnetic pressure to occur producing higher sheet displacements and this optimum time is related to the spiral coil geometry, and mainly to pulse unit parameters. In other words, there exists an optimum discharge current frequency for each EMF process.