Shear horizontal guided wave transducer based on a novel piezoelectric crystal: KCsMoP₂O₉ grown by kyropoulos method

The fundamental shear horizontal (SH₀) guided wave transducer shows unique promise for non-destructive testing and structural health monitoring in oil pipelines, railway tracks, solar power plants, and beyond due to its non-dispersive characteristics. Under this background, it is desirable to explore the high-performance piezoelectric crystals to develop the SH₀ guided wave transducers. Herein, a novel piezoelectric crystal KCsMoP₂O₉ (KCMP) with dominant face shear mode d₁₄ was grown by Kyropoulos method and proposed to excite and receive the SH₀ wave based on the finite element simulation. The resonance frequency was found to be 190 kHz with the designed size of 6 mm × 6 mm × 1.5 mm. The group velocity of generated wave packet was determined to be 3040 m/s, affirming that the detected signal was the SH₀ wave. The simulated and experimental results demonstrated the exceptional ability of KCMP-based guided wave transducer to generate and detect obvious SH₀ waves in two orthogonal principal directions over a wide frequency range (160–360 kHz). Additionally, the KCMP-based SH₀ wave transducer showcases its excellent defect localization ability with high signal-to-noise ratio (~ 30 dB), demonstrating its great potential for application in non-destructive testing and structural health monitoring.