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In this study, numerical simulations of electromagnetic forming (EmF) for automotive sheet metals with flat spiral coil were performed in order to analyze electromagnetic, mechanical behaviors in EmF process. Two automotive sheets which are 5J32 aluminum alloy sheet and DP780 high strength steel sheet having thickness of 1.0mm were utilized. Numerical simulations were conducted with the commercial software LS-Dyna, which is able to fully couple with electromagnetic and mechanical as well as thermal natures in three dimensional spaces. From numerical analysis, electromagnetic quantities such as Lorentz force and mechanical quantities such as deformed shape of sheet metals were examined. At low charge voltage, the simulations of the deformed shape for two workpiece blanks have a good agreement with the experiments.

In this study, electromagnetic forming behavior of automotive aluminum alloy sheet was evaluated. The 5J32 aluminum alloy sheets with thickness of 1.0mm was utilized. The electromagnetic forming system (EMFS) with maximum energy capacity of 120kJ was used with the helix type coil and open die cavity in order that the targeted hemi elliptical protrusion were freely formed. Forming shape, heights and springback amounts after forming were investigated with increasing the initial voltage. The hemi elliptical protrusion was formed without failure up to 9.0kV and was failed at 9.5kV. As increasing the input voltages, the forming heights and the springback of the hemi elliptical protrusion were increased.