A theoretical procedure for detection of simulated cracks in a pipe by the direct current–potential drop technique

Abstract

Based on the direct current–potential drop (dc–pd) technique, an efficient theoretical detection procedure is developed to identify the existence of simulated cracks in a pipe. By this procedure, the electric potential on a ‘pseudo’ perfect pipe needs to be calculated in advance by finite element method. The proposed defect influence factor, which is defined as the ratio of the electric potential of the defective pipe divided by that of the ‘pseudo’ perfect one, is then employed to reveal the effect of cracks on the electric potential. By depicting the contours of the defect influence factor with sufficient resolution, not only the position, but also the shape and length size of cracks in the pipe can be identified accurately by the detection criterion devised in this work. The types of detectable through-wall cracks include circumferential crack, inclined crack, and multiple cracks. Good detection results show the merits of the procedure developed for the identification of the simulated cracks as described above in the pipe structure.