A Comparative Study of Three Types Shear Mode Piezoelectric Wafers in Shear Horizontal Wave Generation and Reception

Guided wave-based inspection has emerged as a promising tool to evaluate the reliability of key components in modern industries. The fundamental shear horizontal (SH(0)) wave is always of great interests for plate-like structures because of its non-dispersion characteristics. However, the generation and reception of SH(0) wave using piezoelectric wafers is not straightforward. In this paper, we firstly define three types shear mode piezoelectric wafers, i.e., the conventional in-plane poled thickness-shear (d(15)) mode, the thickness-poled thickness-shear (d(15)) mode, and the face-shear (d(24)) mode. Then, finite element simulations were conducted to demonstrate their performance in SH wave generation and reception. The results indicated that the face shear d(24) wafer can generate almost single mode SH(0) wave, while both types of d(15) wafers would generate Lamb waves and SH(0) wave simultaneously. Finally, experiments were carried out to check the efficiency of different shear mode piezoelectric wafers in SH(0) wave generation and reception. The results indicated that the d(24) wafer can generate and receive SH(0) wave of high signal to noise ratio (SNR) with high energy conversion efficiency, while the in-plane poled d(15) wafer would generate SH(0) wave of high amplitude and acceptable SNR but with relatively low energy conversion efficiency. The performances of thickness-poled d(15) wafer was not as good as the other two in both SH wave generation and reception. This work will be helpful for the applications of SH waves in plate-like structures.