基于方向调制涡流热成像的防腐漆下裂纹检测

Crack Detection Under Anticorrosive Paint Based on Directional Modulation Eddy Current Thermography

针对传统涡流热成像检测技术中防腐漆层下金属表面裂纹检测信噪比低的问题,提出一种基于方向调制的涡流热成像裂纹检测方法。首先介绍了方向调制涡流热成像的检测原理,介绍了方向调制检测系统;然后根据方向调制方法的数学模型,分析了该方法的可行性,并通过有限元仿真的方法确定调制频率;最后对0.8 mm漆层厚度下不同尺寸裂纹的实验结果进行分析,并且与大功率脉冲涡流热成像方法的检测结果相对比。实验结果表明:方向调制方法对防腐漆下裂纹检测是可行的,并能够有效提高成像信噪比。

Aiming at the problemof low signal-to-noise ratio in conventional eddy current thermography for surface crack detection on metal under anticorrosive paint coating,the directional modulation eddy current thermography method was proposed.First,the detection principle of directional modulation eddy current thermography was expounded,and the detection system was introduced.Then,the feasibility of the method was analyzed theoretically by building the mathematical model.What s more,the modulation frequency was determined by finite element simulation.Finally,the experimental results of different cracks under the thickness of 0.8 mm paint layer were analyzed and compared with the high power pulsed eddy current thermography.The results show that the directional modulation eddy current thermographyis able to detect the cracks under anticorrosive paint coating and enhancesignal-to-noise ratioeffectively.