A benchmark problem for computation of ΔZ in eddy-current nondestructive evaluation (NDE)

Experimental results are presented for the change in coil impedance ΔZ when a circular air-cored coil carrying an alternating current of fixed frequency is scanned across a rectangular slot in an aluminium alloy plate. It is proposed that these measurements be used as a benchmark test to verify theoretical calculations of probe response in eddy-current NDE.