Development of a very fast simulator for pulsed eddy current testing signals of local wall thinning

A very fast numerical solver is developed for simulation of pulsed eddy current testing (PECT) signals caused by volumetric defects by introducing a database-type fast eddy current testing (ECT) simulation scheme for single frequency problems to the Fourier-series and interpolation-based PECT signal simulation code. First, the PECT signal simulation method based on a Fourier series scheme and an interpolation approach is briefly described. Then, a database-type fast numerical solver for single frequency ECT problems is introduced to the Fourier-series-based PECT simulation to enhance simulation efficiency. To cope with fast PECT signal simulation of 3D local wall thinning defects, a 2D shifting symmetry scheme is proposed for inspection targets of both plate and straight pipe geometries to reduce the computational burden required to establish databases of the unflawed field, which are necessary for fast ECT signal simulation. Using these strategies, a very fast numerical solver is developed for simulation of PECT signals of local wall thinning, and its validity is verified by comparing its numerical results with measured PECT signals and with those simulated using a conventional numerical code.