Development of an omni-directional shear horizontal wave transducer based on a radially poled piezoelectric ring

For the inspection of large plate-like structures, the omni-directional guided wave transducer-based system has been regarded as an effective tool since only a few transducers are required to cover the entire inspection area without blind zones. In comparison with Lamb waves, the shear horizontal (SH) wave is more promising because its fundamental mode is non-dispersive. In this work, we proposed an omni-directional SH wave piezoelectric transducer (OSH-PT) based on a radially poled d ₂₄ -mode PZT ring. Both the finite element simulations and experiments were carried out to demonstrate its performance in generating and receiving SH wave. Results showed that the radially poled OSH-PT could generate single-mode SH wave and receive SH wave only over a wide frequency range from 70 to 200 kHz. The obtained signal-to-noise ratio can reach up to 26 dB in generation and 24 dB in reception. The omni-directivity of this OSH-PT is also very good with the deviation only about 6% in both generation and reception of SH wave. Considering its easy fabrication, low cost and superior performances, this proposed OSH-PT may promote the applications of SH wave-based inspection in structural health monitoring and nondestructive testing.