Numerical Solutions to Eddy-current Reflection Coefficient

In the analytical model of eddy-current (EC) testing, the reflection coefficient (RC) plays a crucial role in the calculation of mutual impedance and inductance. The RC describes the reflection characteristics of test pieces concerning incident electromagnetic waves and determines the phase of EC signals. Previously, the RC was computed using analytical solutions. However, obtaining it for test pieces with complex geometries proved challenging, limiting its application, e.g., in the calculation of defect signals. This study proposes a numerical solution to RC based on the second-order vector potential (SOVP). For metallic planar and cylindrical structures, the RC solution is calculated using numerical methods. In numerical simulations, the RC values obtained through the proposed method align well with analytical solutions. When compared with the finite element method (FEM) solution for coil inductance, the proposed method demonstrates fast and accurate inductance solutions for ferrite-core coils used in test pieces with defects.