"A Flexible Wireless Sensor based on SRR for Nondestructive Detection of Metal Crack"

"To meet the demand for wireless, passive, and real-time detection of surface cracks in infrastructures such as bridges and pipelines, this paper designs a crack sensor based on the Split Ring Resonator (SRR) structure. Firstly, the key parameters of the sensor are optimized using HFSS software to obtain a design scheme with high Q-factor. The electric field distribution characteristics of the sensor are analyzed, and the response of its resonant frequency is verified by simulating the variation of crack width, thus confirming the feasibility of the sensor for crack detection. Then, a 0.1 mm-thick flexible PI film is selected as the substrate, and the sensor fabrication is completed via the gold plating process. Finally, a test platform is built to verify the sensor performance. The test results show that the sensor can achieve non-contact crack width detection with a sensitivity of 60 MHz\/mm. This sensor with the advantages of flexibility, miniaturization and networkability, exhibits broad application potential in surface crack detection for bridges, pipelines and other related fields."