Abstract
A numerical dc-PD (direct current-potential drop) technique is establishedfor the identification of possible defects existing in an electric conductive plate. Such defects include holes, notches and cracks. For the plate with holesor notches, the conventional finite element method is employed. However, for theplate with multiple cracks, the conventional finite element method is not suff-icient because of the difficulty in modelling the crack tips. For those multiplecracks problem, due to the similarities between the governing equations in heattransfer and electrostatics, the finite element alternating method (Chen and Chang, 1994) for the heat conduction analysis of multiple cracks is modified inthis work to calculate the electric potential distribution. The defect influencefactor (the electric potential of the defective plate divided by that of the pe-rfect plate) is devised to show the influence of defects on the electric potent-ial distributions. By depicting the contours of the defect influence factor, theshape, size, number and location of defects can be accurately identified. Goodagreement between the computed results and experimental data shows the merits ofthis technique.