Numerical analysis of eddy current NDT for a tube with cracks using 3D indirect BIEM

In this paper, the 3-dimensional indirect boundary integral equation method (BIEM) is applied to the numerical analysis of eddy current non-destructive testing (NDT) for a tube with cracks. The indirect BIEM is developed in terms of the equivalent surface current density and equivalent surface charge density on the interface. The existence and type of the crack in the pipe can be determined from the distortion of the magnetic charge density distribution. The impedance signal is calculated from the equivalent surface charge density without calculating the self inductance. The axisymmetric and the 90-degree circular outer crack problems are calculated as an example. The result shows the usage of the indirect BIEM in the area of eddy current NDT.