Field Distribution Around Surface Cracks in Metallic Cylindrical Structures Excited by High-Frequency Current-Carrying Coils of Arbitrary Shape

We propose an efficient modeling technique for the theoretical prediction of magnetic field distributions around surface cracks in metallic cylindrical structures due to high-frequency alternating-current-carrying coils of arbitrary shape. In this technique, a closed-form solution in Fourier domain is derived that extends the governing Laplace equation inside the crack to the regions outside the crack. This is done by introducing a boundary condition that is based on the conservation of magnetic flux. The validity of the proposed model is demonstrated by comparing the simulation results of several case studies with measurements and those obtained using a commercial finite integration technique code.