Efficient FEBI-based kernel-independent and truncation algorithm for predicting signals of 3D ECNDT with fast frequency sweeps in B-scan

This paper presents an accelerated finite element boundary integral (FEBI) method enhanced by kernel-independent and truncation (KIT) techniques for efficient simulation of 3D arbitrary-shaped eddy current non-destructive testing (ECNDT) in B-scan with frequency sweeps. In FEBI, the boundary integral equation (BIE) generates a full matrix after discretisation, while the matrix generated by FEM is sparse; thus, the one by BIE is dominant. To alleviate the computational costs and accelerate the solving process in handling large-scale 3D ECNDT problems, the KIT technique is applied for the matrix of BIE. In consideration of the exponential decay of Green’s function in the metal, the KT technique is applied to eliminate redundant information in the KI-compressed matrices to further improve the efficiency. The diagonal dominance properties in the interactions of the electric current-electric field and magnetic current-magnetic field in the BIE are analysed separately to determine appropriate KIT thresholds. To further enhance the solver’s efficiency in predicting the signals of B-scan with frequency sweeps, a Kriging interpolation model is studied to ensure overall performance. The results show that the proposed solver maintains remarkable accuracy comparable with experimental and numerical methods while achieving significantly improved computational efficiency.