Three-dimensional profile reconstruction of a natural SCC colony through electromagnetic NDT methods

1)通过提出的反问题算法得到了应力腐蚀裂纹群的三维轮廓。我们发现，启发式学习算法，如遗传算法和蚁群算法是不有效的深度尺寸反演问题的涡流检测信号。通过仿真验证了三维磁信号并不能提高深度测量精度。2）研究了均匀涡流和旋转涡流检测技术在高速条件下对裂纹群的检测。仿真和实验结果表明，均匀涡流和旋转涡流检测对速度的敏感性低于传统涡流检测。3）通过检测概率分析比较了均匀涡流和旋转涡流检测技术的性能。进一步研究了旋转涡流的产生机理。结果表明，旋转涡流检测并不总是优于均匀涡流检测。4）将旋转涡流检测结果转换为均匀涡流检测结果的算法在铁磁材料上进行了试验。结果表明，该算法也是有效的。在检测铁磁材料时，可以将扰动涡流和漏磁的磁信号分离出来。5）在日本完成了整个工作，并向JSPS提交了最终报告。

1) Obtained the three-dimensional profile of stress corrosion crack colonies through the proposed inversion problem algorithm. We found that heuristic learning algorithms such as genetic algorithm and ant colony algorithm were not effective in depth sizing inversion problem using the signal of eddy current testing. Through simulation method, we confirmed that employing three dimensional magnetic signals did not improve the depth sizing accuracy.2) Studied the detection of crack colonies using uniform and rotating eddy current testing techniques in high speed. The simulation and experiment results indicate that uniform and rotating eddy current testing were less sensitive to speed than traditional eddy current testing.3) Compared the performance of uniform and rotating eddy current techniques through probability of detection analysis. Moreover, the mechanism of rotating eddy current was studied further. The results indicated that rotating eddy current testing is not always better than uniform eddy current testing. The orientation of eddy current should be selected.4) The proposed algorithm for transforming the results of rotating eddy current testing to ones of uniform eddy current testing was tested on ferromagnetic material. The results indicated that the algorithm is also effective. When detecting ferromagnetic material, we can separate the magnetic signals of disturbed eddy current and magnetic flux leakage.5) Finished the whole work in Japan and submitted finial report to JSPS.