Recent Developments in Modeling Eddy-Current Probe-Flaw Interactions

A number of industries have been traditional users of eddy-current technology in nondestructive evaluation (NDE). The traditional mode of eddy-current inspection has been ‘monostatic,’ in which a single probe is used as both a ‘transmitter’ and ‘receiver’ Research in these industries now indicates the value of using ‘bistatic,’ or even ‘multistatic’ probe configurations, in which a single probe is used as a transmitter, and one or more probes are used as receivers. The probes may be either air core, or ferrite core, or perhaps a combination. Some examples of bistatic configurations are the split-core differential probe, and remote-field probes. The industry is turning to computer codes that are based on sophisticated computational electromagnetics algorithms in order to design these probes, and to interpret the signals that arise from the interaction of these probes with flaws.