基于远场涡流的管道局部缺陷定量评估方法

在基于远场涡流的管道缺陷定量检测中,设置12个紧贴内管壁、周向均匀分布的传感器作为接收线圈来实现管道局部缺陷的检测。当发射线圈处于管道缺陷位置时,传感器检测的远场涡流相位信号中叠加了发射线圈处缺陷所造成的伪峰信号,影响了传感器处管道缺陷定量分析的正确性;为了去除伪峰信号,在远场区域,设置了与发射线圈同轴的双接收线圈。去除伪峰后的传感器检测信号再进行强局部线性回归和小波阀值去噪处理,得到能真实反映管道局部缺陷的特征信号;最后,基于特征信号,提出了分别适用于单支管道和拼接管道的缺陷定量评估方法。通过实验验证,该评估方法在管道缺陷的定量检测中具有很好的实用性。

Research on local defects quantification of pipes based on RFEC testing

In the quantitative detection of pipeline defects based on remote field eddy current(RFEC),setting 12 uniformly distributed sensors to realize pipeline defection. However, sensor reception signals involved in the spurious peak when the transmitting coil is in the position right of the pipeline defects, which affects the accuracy of the quantitative analysis of pipeline defect. For removing spurious peak, the two coaxial receiving coils are applied to get two time shifting feature signals. After removing spurious peak from the sensor signals, applying robust locally weighted regression algorithm and wavelet threshold de noising, the characteristic phase reflecting the local defects of pipeline can be obtained; according the characteristic phase, a quantitative evaluation method for the defects of single branch pipe and joint pipe is proposed. At last, the evaluation method is verified by the experiment, which turns out to be practical in the quantitative detection of pipe defects.