基于谱分析的脉冲涡流缺陷3D分类识别技术

Pulsed eddy current defect 3D classification technique based on frequency spectrum analysis

脉冲涡流检测技术是一种快速发展的无损检测方法,而相应的缺陷分类识别是缺陷检测与评估中的关键步骤之一。本文首先对脉冲涡流检测技术进行了频谱分析,得出下表面缺陷主要影响低频成分,而表面缺陷同时影响低频成分与高频成分的结论;其次,设计了脉冲涡流矩形传感器和腐蚀型缺陷模拟试件;最后,在对上下表面的缺陷分别进行频域分析的基础上,提出了选择3个特定频率点的幅值作为特征量对缺陷进行3D分类识别的方法。实验结果证明本文所提出的方法可对3 mm铝板上下表面腐蚀缺陷进行有效的分类识别。

Pulsed Eddy Current（PEC） testing is a new emerging and effective electromagnetic non-destructive testing and evaluation（NDTE） technique.The main purpose of this study is to identify surface defects and sub-surface defects using frequency spectrum analysis based on rectangular pulsed eddy current sensor.After theoretical analysis of PEC,a conclusion has been drawn that the surface defects affect high and low frequency components while the sub-surface defects affect high frequency component.Experiment results show that different classes of defects can be identified and classified effectively using frequency spectrum analysis.In order to verify the performance of the proposed method,blind test was carried out and test results show that the proposed method is effective to classify the corrosion types of the defects in specimen with a thickness of 3mm.