Circumferential SH waves in piezoelectric layered cylinder for covered layer and substrate in opposite polarization

Circumferential horizontal shear (SH) surface acoustic wave propagation is evaluated in the piezoelectric cylindrical layered structures for covered layer and substrate in opposite polarization. The special functions method is used to solve the coupled governing equations. Through a numerical example, we discuss the dispersion relation and electromechanical coupling factor of SH waves in the layered cylinder and the homogeneous cylinder. The mechanical displacement distribution is illustrated. It is found that the energy of SH waves focus on the covered layer for the piezoelectric cylindrical layered structures. Results provide theoretical guidance not only for experimental measurement of material properties but also for nondestructive evaluation using the ultrasonic wave devices.