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 and 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 d24 PZT wafer as actuator and face-shear d36 PMN-PT wafers as sensors, pure SH0 wave was successfully excited in an aluminum plate from 140 kHz to 190 kHz. Then, it was shown that the face-shear d24 PZT wafer could receive the SH0 wave only and filter the Lamb waves over a wide frequency range (120 kHz to 230 kHz). The directionality of the excited SH0 wave was also investigated using face-shear d24 PZT wafers as both actuators and sensors. Results show that pure SH0 wave can be excited symmetrically along two orthogonal directions (0{\deg} and 90{\deg} ) and the amplitude of the excited SH0 wave can keep over 90% of the maximum amplitude when the deviate angle is within 30{\deg}. This work could greatly promote the applications of SH waves in NDT and SHM. 
Hongchen Miao, Qiang Huan, Faxin Li
cond-mat.mtrl-sci