Achievement of accuracy in FEM-based solutions by applying the Theorem of reciprocity

Often, the computing of differences of numerically obtained solutions is a crucial point in achieving results of high accuracy. Nevertheless, several applications, like the identification of unknown hidden objects with the aid of exciting and receiving coils, necessitate the building of differences. It is shown that the application of the theorem of reciprocity or of a zero-solution scheme improves the accuracy sustainably. On a ferrous conductive iron grid the investigations are demonstrated. The appearance of eddy-currents not only in the rods but also in the meshes of the iron grid enforces a very fine and accurate discretization of the FE-model, additionally