Study on Nondestructive Testing for Bonding Defects in Aerospace Composite Based on Terahertz Image
PAN Zhao1,WEN Yin-tang1,2,ZHENG Xiao-kang1,3,CUI Yao-yao1
1. Key Laboratory of Measurement Technology & Instruments of Hebei Province, Yanshan University, Qinhuangdao, Hebei 066004, China
2. Institute of Defense Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004, China
3. Fire Equipment & Environmental Control Equipment Brunch Factory, Tianjin Aviation Electro-Mechanical Co. Ltd., Tianjin 300300, China
Abstract Thermal insulation aerospace composite and metal substrates’ bonding defects are tested by the reflection type frequency modulated continuous terahertz wave testing system which the frequency range is 0.23-0.32THz. Thermal insulation composite and metal substrates are bonded by epoxy resin adhesive as the experimental sample. Bonding defects of the adhesive interface can be detected visualized by image neighbor focal plane. Otsu’s threshold algorithm and FCM clustering algorithm is applied to get the segment of defect binary images combined with median filtering, then have the defect area by calculating the number of pixels. Compared with the samples which have known defect area, the FCM clustering algorithm is finally used because of the better segmentation effect and the error is about ±5%.
PAN Zhao,WEN Yin-tang,ZHENG Xiao-kang, et al. Study on Nondestructive Testing for Bonding Defects in Aerospace Composite Based on Terahertz Image[J]. Acta Metrologica Sinica, 2018, 39(4): 471-475.
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2018, Vol. 39 
