Reconstruction of cracks with multiple eddy current coils using a database approach

This paper presents some recent studies dealing with flaw reconstruction using eddy current testing. The locations of parallel planar cracks in an Inconel 600 plate specimen are determined and the shapes of them are reconstructed at the same time using the signals from a multi-pancake coil probe. The reconstruction strategy, consisting of a data base used fast forward solver and a first order optimization algorithm, relies on the minimization of the nonlinear least square residual function. Validity of the inverse analysis method is investigated with respect to the influence of the arrangement of scanning paths. The efficiency of the computation is also discussed.