Non-destructive inspection of CFRPs using phase-transformed induction heating thermography

本文对cfrp的感应加热无损检测进行了研究。在常规温度图像的基础上，对温度-时间关系进行傅里叶变换得到的相位图像用于缺陷检测。对人工缺陷CFRP试样进行的实验表明，由于感应线圈的形状，温度图像会产生不均匀加热，但在一定频率下，相位图像中的不均匀加热被抑制。由于这种抑制作用，温度图像中被不均匀加热掩盖的缺陷在相位图像中被清晰地检测出来，从而提高了缺陷的可检测性。理论计算表明，不均匀加热对相位图像的影响周期性减小，周期等于加热时间的倒数。

Non-destructive inspection of CFRPs using induction heating was studied in this study. In addition to conventional temperature images, phase images obtained by applying Fourier transform to temperature-time relation was used for defect detection. Experiments for CFRP specimens with artificial defects show that, though nonuniform heating occurred in temperature images owing to the shape of induction coil, the nonuniform heating was suppressed in the phase images at a cirtain frequency. Because of this suppression, the defects obscured by nonuniform heating in the temperature images were clearly detected in the phase images, resulting in improved defect detectability. Theoretical calculations revealed that the influence of nonuniform heating in the phase images periodically decreased and that the period was equal to the reciprocal of heating duration.