Numerical simulation of pulsed eddy-current nondestructive testing phenomena

A general-purpose hybrid finite-element and finite-difference computational model developed for the prediction of pulsed eddy-current distribution in metals for nondestructive testing purposes is discussed. The numerical model uses an axisymmetric formulation to study coil configurations suspended over a metallic specimen. As a driving function, a pulsed Maxwell-distributed current density is applied. Resulting eddy-current distributions are discussed as a function of conductivity, permeability, and lift-off. The transition voltage response of a coil over an infinite half-space is numerically computed and compared to the solution obtained by a novel analytical approach. The numerical model is then used to determine the induced voltage due to a surface-breaking flaw