Electromagnetic impulse calibration of high strength sheet metal structures

This study focused on using electromagnetically generated impulses to correct dimensional errors resulting from springback on two different geometric features. Modification or correction of a corner feature is considered first. A simple linear actuator is used to correct springback on a simply bent high strength aluminum alloy (AA 5754) and a high strength steel alloy (DP 600). It is shown to be possible to fully correct for springback using a net-shape die with both materials with higher electromagnetic discharge energies being required for the steel. The second geometric feature considered is a sidewall curl 'defect' that is the result of bending and unbending U-Channel drawing. A serpentine actuator and net-shape die were shown effective at correcting for this defect in both DP 600 and TRIP 700 high strength steels. A somewhat higher forming energy is required for effective shape correction in the higher strength TRIP 700 alloy. A detailed mechanistic understanding of springback correction remains elusive, but these results are consistent with several other studies in the literature that show this is an effective means to control springback.