Diffusion Velocity of Eddy Current in Metallic Plates Using Point-Tracing Method

Pulsed eddy current (PEC) is based on the electromagnetic induction principle, which is widely used in the metal industry for nondestructive testing (NDT) due to its unique advantages, such as fast response, great penetration depth, and lift-off tolerance. Eddy current diffuses in a complex manner with the diffusion velocity uneven in space and time. A full picture of the diffusion velocity field enhances physical insight into PEC detection. This article proposes a novel point-tracing method for velocity field calculation. The eddy current diffusion process is divided into three stages and their velocity fields are calculated, respectively. The complete field is then visualized. The calculated results correspond to the phenomenon observed in numerical simulations. Furthermore, the relationship has been analyzed between the properties of the planar conductor, probe lift-off, and the diffusion velocity field, according to the proposed method.