基于频谱分析的脉冲涡流检测提离消除技术

脉冲涡流检测中由于探头倾斜等原因容易产生提离效应，严重影响缺陷的定量精度。利用激励脉冲频率成分丰富的特点，提出了一种基于频谱分析的提离效应消除新方法。通过试验发现，经该方法处理后的有提离的原始检测信号在低频部分已基本重合，消除了提离效应对低频的影响，且可通过提取低频特征值对缺陷的深度进行定量。试验结果证明，该方法可以有效地消除提离效应，提高缺陷的定量检测精度。

The Reduction Technology of Lift-off Effects for Pulsed Eddy Current Testing Based on Frequency Spectrum Analysis

It was prone to bring lift-off effects in pulsed eddy current testing（PECT） because of probe incline, which influenced badly to the precision of quantification of defects. Using the feature that the pulsed excitation has affluent frequency ingredients, a new technology for reducing the lift-off effects based on frequency spectrum analysis was proposed. Through the testing, it was found that the low-frequency part of the processed signal by the technology has been almost in agreement with the original testing signal with lift-off, the effects have been reduced and the depth of the defects can be measured through getting the low-frequency characteristic peaks. The results showed that significant reduction in the effects was achieved and the precision of quantification detection for defects was improved.