Excitation and reception of pure shear horizontal waves by using face-shear d24 mode piezoelectric wafers

The fundamental shear horizontal (SH0) wave in plate-like structures is of great importance in non-destructive testing (NDT) and structural health monitoring (SHM) as it is non-dispersive, while excitation or reception of SH0 waves using piezoelectrics is always a challenge. In this work, we firstly demonstrate via finite element simulations that face-shear piezoelectrics is superior to thickness-shear piezoelectrics in driving SH waves. Next, by using a newly defined face-shear d(24) PZT wafer as an actuator and face-shear d(36) PMN-PT wafers as sensors, pure SH0 wave was successfully excited in an aluminum plate from 130 to 180 kHz. Then, it was shown that the face-shear d(24) PZT wafer could receive the SH0 wave only and filter the Lamb waves over a wide frequency range (120-230 kHz). The directionality of the excited SH0 wave was also investigated using face-shear d(24) PZT wafers as both actuators and sensors. Results show that pure SH0 wave can be excited symmetrically along two orthogonal directions (0 degrees and 90 degrees)and the amplitude of the excited SH0 wave can keep over 90% of the maximum amplitude when the deviate angle is within 30 degrees. This work could greatly promote the applications of SH0 wave in NDT and SHM.