The detection and measurement of symmetric corner cracks by the a.c. field method

Abstract

An unfolding method, developed earlier for cracks in plane surfaces, is extended in this work to provide an approximate mathematical model for the perturbations produced by a symmetrical corner crack when interrogated by a surface electric field. The model disregards the nonuniform nature of the current distribution upstream of the crack which is produced by the presence of the corner, and this simplification leads to unfolded field problems of plane Laplacian form. The Schwarz-Christoffel transformation is applied here in their solution. Experimental measurements on slots cut on steel blocks to simulate corner cracks are found to be in good agreement with the predictions of the model. © 1986 Plenum Publishing Corporation.