Surface Crack Configuration Detection System by DC Potential Drop Method

Abstract

Surface crack configuration can be detected by DC potential drop method. The simplified inverse method for determining the surface crack shape has been developed based on the FEM analysis for various deep surface cracks with different aspect ratios. The method has been applied to fatigue surface cracks introduced at the inside surface of stainless steel pipes. The cracks shape could be estimated with an accuracy of ±0.3mm in depth. In order to verify the method, a pipe internal scanner was devised for the measurement of potential difference distribution in 12 inch pipe. The scanner can pass through not only an elbow but also a vertical pipe. The crack position and the detailed crack configuration can be analyzed automatically from the measured potential difference distribution.