A new omnidirectional shear horizontal wave transducer using face-shear (d₂₄) piezoelectric ring array

The non-dispersive fundamental shear horizontal (SH₀) wave in plate-like structures is of practical importance in non-destructive testing (NDT) and structural health monitoring (SHM). Theoretically, an omnidirectional SH₀ transducer phased array system can be used to inspect defects in a large plate in the similar manner to the phased array transducers used in medical B-scan ultrasonics. However, very few omnidirectional SH₀ transducers have been proposed so far. In this work, an omnidirectional SH₀ wave piezoelectric transducer (OSH-PT) was proposed, which consists of a ring array of twelve face-shear (d₂₄) trapezoidal PZT elements. Each PZT element can produce face-shear deformation under applied voltage, resulting in circumferential shear deformation in the OSH-PT and omnidirectional SH₀ waves in the hosting plate. Both finite element simulations and experiments were conducted to examine the performance of the proposed OSH-PT. Experimental testing shows that the OSH-PT exhibits good omnidirectional properties, no matter it is used as a SH₀ wave transmitter or a SH₀ wave receiver. This work may greatly promote the applications of SH₀ waves in NDT and SHM.