1997 年 63 巻 614 号 p. 2235-2242
The electric field in a conductive material with multiple circular cracks is analyzed by means of the crack-flow modification method (CFMM). It is found that the increase in the potential difference of the cracked meterial normalized by the potential difference without cracks, ΔV/V0, is in proportion to the product of the effective volumetric crack density and the mean of the cubed crack radius, neff[γ3]m. This universal relationship is also valid for multiple semi-circular cracks on the surface of the material and gives the physical meaning of damage detected by the direct current electrical potential method.