Detection of Debonding Defects Between Radar Absorbing Material and CFRP Substrate by Microwave Thermography

Microwave thermography (MWT) is a non-destructive testing method based on the principle of microwave heating, which is widely used in the detection of debonding defects of various composite materials. Based on the principle of Microwave thermography (MWT), a resonant cavity microwave thermography detection system is proposed in this paper. The temperature variation characteristics of debonding defects in carbon Fiber Reinforced Polymer (CFRP) and radar absorbing material (RAM) are studied. This system consists of a resonator microwave source, an infrared thermal imager, a fan and two computers. This system successfully detects such defects at the pixel level by thermally loading the test piece, collecting the temperature change data of the test piece by the thermal imager, analyzing the temperature difference between the normal area and the defect area. In this paper, the advantages of microwave on the radar absorbing material (RAM) with large specific heat capacity and high thermal conductivity, high heating efficiency, large heating area and negligible damage to the radar absorbing material are verified, and the high performance of the detection system is verified. The experimental results show that microwave thermography can realize high-precision debonding detection and positioning of multilayer heterogeneous radar absorbing material (RAM).