CFRP/Al蜂窝结构缺陷巴克编码热波检测及匹配滤波

Barker coded thermal wave detection and matched filtering for defects in CFRP/Al honeycomb structure

CFRP/Al蜂窝板构件长期服役于恶劣环境,易引发脱粘和积水等涉及运行安全的缺陷。以同时含有脱粘和积水缺陷的CFRP/Al蜂窝复合板材为检测试件,运用巴克编码调制脉冲压缩信号驱动卤素灯作为外部激励源,用红外热像仪采集试件表面的红外热图序列。设计并运用三维匹配滤波器对所采集的图像序列进行处理,在4种不同量化方式的条件下,获得有关脱粘和积水缺陷的8个热波响应结果,并对这些结果进行多角度对比分析及信噪比评估。结果表明:巴克编码激励具有调制简单、易实现等优势,结合三维匹配滤波器可有效抑制红外热图背景噪声和提高信噪比,能实现在低功率热激励条件下对复合材料内部脱粘和积水缺陷的有效检测。

CFRP/Al honeycomb panel components have been used in harsh environment for a long time, which is easy to cause debonding and water accumulation and other defects related to operation safety. Taking CFRP/Al honeycomb composite plate with debonding and water accumulation defects as the test sample, the halogen lamp driven by Barker coded modulation pulse compression signal was used as the external excitation source, and the infrared thermal image sequence of the sample surface was collected by infrared camera. Three dimensional matched filter was designed and used to process the acquired image sequence. With 4 different quantization methods, 8 thermal wave response results of debonding and water accumulation defects were obtained, and these results were compared and analyzed from multiple aspects and the signal-to-noise ratio(SNR) was evaluated. The results show that Barker coded excitation has the advantages of simple modulation and easy implementation, and it can effectively suppress the background noise of infrared thermal image and improve the SNR by combining with three dimensional matched filter, and can effectively detect the internal debonding and water accumulation defects of composite materials under the condition of low-power thermal excitation.