Metal plate deformation under magnetic field pulse of complex shape.

A dynamic deformation of sheet magnetic and nonmagnetic metal workpieces under a combination of a slowly varying primary magnetic field and a sequence of short magnetic field pulses with the opposite polarity is studied. This regime corresponds to backward electromagnetic forming. A fast motion of the workpiece induces an additional electromotive force in a discharge circuit and substantially alters a shape of the current pulse in an inductor. During the short opposite pulses, the Lorentz and magnetization components of the magnetic pressure on the magnetic workpiece demonstrate an unusual behavior, that is, the Lorentz pressure is attractive and the magnetization one is predominantly repulsive relative to the inductor. This phenomenon is discussed in terms of a two-dimensional axisymmetric problem. [ABSTRACT FROM AUTHOR]