3D eddy currents in multiply connected thin sheet conductors

A method for calculating 3D eddy current distributions in thin sheet conductors of arbitrary shape and of small thickness relative to the skin depth of the material at the excitation frequency is described. The regions surrounding the conducting sheets are modelled using magnetic scalar potentials and the sheet current is represented by a scalar stream function. The field equations are in differential form and are modelled numerically using finite elements. The resulting sparse symmetric set of equations is solved using the pre-conditioned bi-conjugate gradient technique. Discontinuities in sheet conductivity and thickness can be modelled. This is used to simulate the effect of holes in the sheets.