Asymptotic boundary element methods for thin conducting sheets in two dimensions

Shielding sheets are commonly used in the protection of electronic devices. With their large aspect ratios they become a serious issue for the direct application of boundary element methods due to the occurring almost singular integrals. Impedance transmission conditions allow for boundary element formulations where only sheet mid-line has to be triangulated. We propose and analyse boundary element methods of second kind for impedance transmission conditions of two different types for the time-harmonic eddy current problem in two dimensions. In numerical experiments we study the effect on the magnetic shielding efficiency of the discretisation error due the boundary element discretisation and the modelling error due to the impedance transmission condition