Koch curve fractal geometry excitation probe for eddy current non-destructive testing

The sensitivity of eddy current (EC) nondestructive testing (NDT) probe is mainly related to the EC distribution in conductive specimens. To improve the sensitivity of this type of probes, a planar probe with a Koch curve excitation coil that can induce a multiradius EC distribution is proposed. FEM simulation was conducted to visualize the electromagnetic field distribution and understand the operating principle of the probe. A planar EC probe with a Koch curve excitation coil and an experimental measurement system was developed. A set of aluminum plates with different sizes of defects were tested to assess the improved sensitivity of the Koch curve-based probe.