Evaluation of the distribution of multiple circular cracks with random radii and angles by direct current electrical potential difference method

Electric field analysis for multiple circular cracks with different radii and angles subjected to direct electric current was carried out by the crack- current modification method (CCMM). It was found from the analysis that the increase in the potential difference normalized by the value in the case of no crack, ΔV/V₀, is in proportion to the product of the volumetric density of the cracks and the mean of the cubed crack radius and the squared cosine of the crack angle to the current direction, n_v[r³ cos² θ]_m. This relationship held for any crack distribution conditions discussed in this study. Using the relationship, a method for non-destructive evaluation of the distribution of circular cracks by means of direct-current potential difference method (DC-PDM) was proposed. The validity was numerically examined for two example cases.