Efficient numerical simulation of DC potential drop signals for application to NDT of metallic foam

Abstract

Purpose – Direct current potential drop (DCPD) testing is a potential nondestructive testing method for quality control of the metallic foam (MF). The purpose of this paper is to develop a numerical technique for the efficient simulation of the DCPD signals of MFs with defects with boundary of complicated shapes. Design/methodology/approach – The concept of multi-medium element (MME) is introduced to treat the boundary of complex-shaped defect. A classification scheme of Gauss integral points is also proposed to select the Gauss points that have to be taken into account in the integral calculation of the coefficient matrix of each MME. Findings – MME is suitable for simulation of DCPD signals due to defects in complicated shapes. The numerical method for calculating the element matrix of the MME is efficient and accurate. The experimental results support the proposed method positively. Research limitations/implications – The code developed in this paper is suitable for the simulation of DCPD signals of MF due to a planar defect. The code for 3D defect is still under development. Originality/value – The concept of MME introduced to deal with the simulation of DCPD signal due to defect with boundary of complicated shape, as well as the numerical technique for element coefficient matrix calculation. The developed method gives possible for the inversion of DCPD signals of complicated defect shape.