A transfer function method for eddy current nondestructive testing

A transfer function method is introduced to eddy current nondestructive testing (ECT) in this paper. Actually ECT is used to investigate the differences of the materials with and without flaws. The transfer function of the tested materials for ECT is defined as the frequency property of the materials. With the transfer function method, the difference is an area bounded by the two transfer functions of the materials with and without flaws, while the impedance method can only provide a few discrete impedance values. Obviously, the area can provide more information of the materials than a few discrete values. The numerical and the experimental studies have proved that the transfer function method is an efficient approach for ECT.