A surrogate model for efficient solutions to transient eddy current evaluation of tubular conductors via analytical and numerical integrated modelling

In an effort to scrutinize transient eddy current testing (TECT) of tubular conductors, it is pivotal to conduct electromagnetic simulations based on either analytical or numerical modelling. Following such contemporary approaches as the finite element modelling (FEM) and extended truncated region eigenfunction expansion (ETREE) modelling, a surrogate model for efficient solutions to TECT is proposed by integrating ETREE and FEM via the reciprocity theorem and superposition principle of electromagnetism. The solutions of the magnetic vector potential for the flawless and defective cases are obtained via ETREE for the unperturbed field and FEM for the perturbed field. The TECT response signal to a tubular conductor subject to a circumferential corrosion can ultimately be predicted by superimposing the defect-free and defective solutions. The proposed surrogate model is subsequently verified through the simulations of the full FEM and experimental results. From the cross-comparison, it is affirmed that the surrogate model inherits the merits of ETREE and FEM, and is thus capable for efficient prediction of the TECT results without much loss in accuracy.