The development of instrumentation to measure the electrical conductivity of mechanical joints in electrically conductive structures

As part of a continuing effort to quantify the electrical performance of airframes, a research project was undertaken to develop instrumentation which could be used to assess the electrical conductivity of mechanical joints. The project consists of two parts: (1) a theoretical analysis to verify the feasibility of the method adopted; (2) the construction of prototype instrumentation. The method adopted was to measure the impedance of a flat, circular test coil when placed above the joint of interest. A preliminary evaluation of the technique, together with a two dimensional analysis of a typical application is described in a previous work (see Proc. International Conference on Computation in Electromagnetics, London, IEE, p.948-51, 1991). The authors describe a three dimensional analysis of the complete problem and two prototype instruments which were developed as a result of the theoretical work