Eddy-current probe impedance due to a surface slot in a conductor

A computational model has been developed for the simulation of eddy-current nondestructive testing. The electric field produced by a probe in the absence of the flaw is determined; then the field induced at the flaw is found. These field calculations are based on volume integral techniques requiring only the region of the scatterer to be discretized. Boundary conditions at infinity and interface conditions at the surface of the conductor are built into the Green's function kernels, thus ensuring that the scattered field satisfies these conditions. The discrete equations are formed using the method of moments and solved using conjugate gradient methods. The proposed model was applied to the calculation of the interaction of two ferrite core eddy-current probes with five simulated EDM notches in a material of conductivity 1.2% IACS, at a frequency of 2 MHz. The results obtained confirm the validity of the proposed method.>