Evaluation of Back-Wall Fatigue Cracks by Means of Remotely Induced Current Potential Drop Technique and Its FEM Simulation

摘要

During operation, different defects initiate and grow in machine components due to fatigue, SCC, etc., and the reliability of components decreases with operating time. The performance and safety have to be maintained by regular and adequate inspection techniques and appropriate treatment. In this study, the applicability of Remotely Induced Current Potential Drop (RICPD) technique to the evaluation of the size of back-wall fatigue cracks was investigated and the possibility of numerical simulation for the RICPD measurements was discussed. Finite Element Method (FEM) analysis for the RICPD measurements on the plate specimen of type 304 stainless steel containing artificial back-wall defects was performed and calculated potential drop changes by FEM simulation for the back-wall defects show good agreement with experimental results. Sizing of back-wall fatigue crack in the plate specimen of type 304 stainless steel with a thickness of 10mm was performed by the RICPD technique. Comparisons between evaluated and actual depths of back-wall fatigue crack reveal that the RICPD technique can perform accurate maximum depth estimation of back-wall fatigue crack with the error of 0.93%.