A thermo-electro-mechanical coupling study of Csaw motions and an application to the ultrasonic spherical motors by TEM–FEM

This paper carries out thermo-electro-mechanical element study of anisotropic and piezoelectric curved surface acoustic waves (Csaw) in uniform materials, and dispersed Csaw of inlaid electrode metals, particularly for a novel type of miniature ultrasonic spherical saw motors. An electro-thermo-mechanical acoustic finite element method is chosen with temperature variation introduced and electric potential condensed, its convergence is verified for mechanical vibration spectrums and piezoelectric surface wave velocities. The coupled acoustic influences of Euler angles and temperature gradients in addition to implanted electrode heights and surface curvatures are evaluated on the piezoelectric surface waves. Numerical results are provided for consistent evaluations, and several conclusions with attained curves are drawn to investigate the electromechanically controlled standing wave drive mechanism.