Reconstruction of deep stress corrosion crack based on a multi-objective optimization evaluation from Eddy Current Testing signals

Sizing of crack profiles with Eddy Current Testing (ECT) signals often underestimates the depth of Stress Corrosion Cracks (SCCs) because of its complicated geometry and conductivity property. In this paper, a multi-objective optimization strategy is proposed for the multi-frequency ECT inversion to improve the sizing accuracy of a deep SCC. A ε-constraint method is applied to solve the multi-objective optimization in order to fully utilize the information from the measured ECT signals of different frequencies. Reconstruction with simulated ECT signals of SCC is conducted and the results reveal that the proposed strategy is effective to improve the sizing precision of a deep SCC.