Shear Horizontal Guided Wave Sensors Based on CTGS Piezoelectric Crystal for High-Temperature Structural Health Monitoring

The development of ultrasonic-guided wave sensors is of great significance for structural health monitoring (SHM). In this work, a shear horizontal (SH) ultrasonic guided wave sensor based on the Ca3TaGa3Si2O14 (CTGS) piezoelectric single crystal is demonstrated. The findings reveal that the CTGS-based ultrasonic guided wave sensor is proficient in transmitting and receiving pure fundamental SH wave (SH0 wave) along two orthogonal main directions (0° and 90°) over a wide frequency range (100–350 kHz), exhibiting strong response to the SH0 wave. Under the driving voltage of 100 V, the peak-to-peak values of the sensor output are 110.8 and 8.0 mV at room temperature and high temperature of 600 °C, respectively. Additionally, the signal-to-noise ratio (SNR) of the CTGS-based SH0 sensor is evaluated to be >18.9 dB even at the elevated temperature of 600 °C. Moreover, the CTGS-based SH0 sensor showcases its reasonable defect localization ability at temperatures up to 600 °C, demonstrating its great potential for application in the high temperature in-situ SHM.