Effect of second current pulse and different algorithms on simulation accuracy for electromagnetic sheet forming

Abstract

In the past, many simulation methods for electromagnetic forming (EMF) just consider the effect of the first half current pulse on electromagnetic forming process. And it is deemed that the sequence coupling method has a higher accuracy than loose coupling method because the effect of workpiece deformation on magnetic analysis is considered. In this work, the loose coupling method and sequence coupling method are both used to investigate how the second half current wave affects the simulation result. If the first current pulse is only considered in the simulation process, higher accuracy can be obtained by loose coupling method at 4,366 Hz of discharge current or sequence coupling method at 2,183 Hz of discharge current. If the second current pulse is also considered, the sequential coupling method can obtain more precise results than loose coupling method in the two different current frequencies. With the increase of displacement, the loose coupling method could cause a bigger overestimation than sequential coupling method. Then, the total resistance in EMF system is adjusted to obtain different damping exponent. It is found that the effect of the second current pulse on sheet deformation increases with the increasing of the discharge frequency.