Defect reconstruction of remote field eddy current belonged to electromagnetic inverse problem in materia Non-Destructive Testing. In view of disadvantages in present defect reconstruction methods, such as over-long time or excessive need for training samples, a new defect reconstruction method based on similar model and genetic algorithm was investigated as follows: similar model between non-axisymetric defect and axisymetric defect was represented, and proportionality factor was deduced by skin depth equation. As a result, the time-consuming forward problem solution in defect reconstruction, which using 3D finite element computation conventionally, was simplified to 2D finite element computation. At the same time, a method designed to accelerate convergence of genetic algorithm was adopted, and more times saving were obtained. Computation results show that, total defect reconstruction time is reduced to 7.6%, compared with directly 3D finite elemet computation, while reconstruction accuracy remains almost the same.
A fast eddy-current non destructive testing finite element solver in steam generator