基于太赫兹时域光谱技术(THz-TDS)对聚乙烯管道接头的老化及常见缺陷进行检测,获得不同老化程度的聚乙烯样品的折射率与吸收系数,并对管道接头的典型缺陷进行成像检测。实验结果表明:随着老化时间延长,聚乙烯样品在0.2~2.0 THz频段内的折射率未发生明显变化,该频段内材料的吸收系数随着老化时间的延长而明显下降。太赫兹图像中缺陷区域与无缺陷区域的像素点存在明显区别,从图像中可以分辨出缺陷的位置及大致轮廓。

Herein, the aging and common defects of polyethylene (PE) pipe joints are inspected based on terahertz time-domain spectroscopy (THz-TDS). The reflective indices and absorption coefficients of PE specimens with different aging time are calculated,and the imaging detection for the typical defects of pipe joints is conducted. It is found that the reflective indices of the PE specimens have no obvious change in 0.2-2.0 THz range after aging for a long time. However, the absorption coefficient shows a decreasing tendency with increasing aging time. Finally, the defects are imaged using reflective THz-TDS. Pixels around the defect areas are different from those around non-defect areas in THz images, and the defect position and outline are revealed in the THz images.