Nondestructive Evaluation of Carbon Fiber Reinforced Polymer Composites Using Reflective Terahertz Imaging

• Published in: Sensors (Basel, Switzerland) Vol. 16; no. 6; p. 875
• Main Authors: Zhang, Jin, Li, Wei, Cui, Hong-Liang, Shi, Changcheng, Han, Xiaohui, Ma, Yuting, Chen, Jiandong, Chang, Tianying, Wei, Dongshan, Zhang, Yumin, Zhou, Yufeng
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 14-06-2016; MDPI AG
• Subjects: carbon fiber reinforced polymer composites; coating debonding; fire-retardant coatings; nondestructive evaluation; terahertz time-domain spectroscopy imaging; fire-retardant coatings; nondestructive evaluation; coating debonding; carbon fiber reinforced polymer composites; terahertz time-domain spectroscopy imaging
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s16060875

Terahertz (THz) time-domain spectroscopy (TDS) imaging is considered a nondestructive evaluation method for composite materials used for examining various defects of carbon fiber reinforced polymer (CFRP) composites and fire-retardant coatings in the reflective imaging modality. We demonstrate that hidden defects simulated by Teflon artificial inserts are imaged clearly in the perpendicular polarization mode. The THz TDS technique is also used to measure the thickness of thin fire-retardant coatings on CFRP composites with a typical accuracy of about 10 micrometers. In addition, coating debonding is successfully imaged based on the time-delay difference of the time-domain waveforms between closely adhered and debonded sample locations.