Numerical simulations and experiments of eddy current tests under various excitation methods

This paper discusses the various excitation methods of eddy current non-destructive testing (NDT). In conventional eddy current NDT, a specimen is drive by an ad or dc current. Consequently, the magnetic field generated in the specimen is aligned in a single direction. However, in order to estimate the shape or position of an unknown defect, a two-dimensional alternating magnetic flux density vector is necessary. In this paper, two-dimensional excitation methods are proposed. The magnitude and phase value are measured and analyzed to obtain information about the defect. Finally, the results of the boundary elements analysis show the availability of these methods. (c) 2004 Elsevier B.V. All rights reserved.