Shear horizontal (SH) waves have received more and more attention in structural health monitoring (SHM) and nondestructive testing (NDT) since the fundamental mode (SH₀) is non-dispersive and only has one displacement component, which is very convenient for signal identification and simulation. In recent years, great progress had been made in exciting single-mode SH₀ wave for SHM. However, it is still difficult to excite high-order SH wave modes at present.

In this work, a piezoelectric interdigital transducer, named SH-IDT, was proposed for selective excitation of the SH wave. By simplifying the bonded SH-IDT to distributed shearing line forces, an explicit formula for the far-field wave displacement was derived and validated through finite element simulations. Then, two SH₁-IDTs working at 1 MHz on a 3 mm-thick plate and 3 MHz on a 1 mm-thick plate were designed and fabricated for exciting the SH₁ mode and suppressing other wave modes. Their performances were examined by using a homemade 2D laser Doppler vibrometer. Nearly perfect wave mode selection and high energy concentration were observed. The displacement amplitude ratios between all the unwanted waves and the SH₁ wave are smaller than 1/10 and this value turned to be as lower as 1/50 when using another SH₁-IDT as the receiver. The half radiation angle of the SH₁-IDT was only about 10°. All the experimental results are in good agreement with the simulation results, which validated the design of the SH₁-IDT. The high selective capabilities of the designed SH-IDT make it very promising for tomography in SHM and it is expected to be widely used in near future.

由于基模（SH ₀）是非色散的，只有一个位移分量，非常方便信号的检测，因此水平剪切波（SH）在结构健康监测（SHM）和无损检测（NDT）中越来越受到关注。识别和模拟。近年来，令人兴奋的SHM单模SH ₀波取得了很大进展。然而，目前仍难以激发高阶 SH 波模式。

在这项工作中，提出了一种名为 SH-IDT 的压电叉指换能器，用于选择性激发 SH 波。通过将键合 SH-IDT 简化为分布剪切线力，推导出了远场波位移的显式公式，并通过有限元模拟进行了验证。然后，设计并制造了两个 SH ₁ -IDT 在 3 mm 厚的板上以 1 MHz 和 3 MHz 在 1 mm 厚的板上工作，用于激发 SH ₁模式并抑制其他波模式。使用自制的 2D 激光多普勒测振仪检查了它们的性能。观察到近乎完美的波模式选择和高能量集中。所有无用波与 SH ₁之间的位移幅度比波小于 1/10，当使用另一个 SH ₁ -IDT 作为接收器时，该值变为低至1/50 。SH ₁ -IDT的半辐射角仅为约10°。所有的实验结果与模拟结果非常吻合，验证了SH ₁ -IDT的设计。所设计的 SH-IDT 的高选择性使其非常有希望用于 SHM 中的断层扫描，并有望在不久的将来得到广泛应用。