This paper proposes an analytical model of a rotary motor driven by an anis
otropic piezoelectric composite laminate. The driving element of the motor
is a three-layer laminated plate. A piezoelectric layer is sandwiched betwe
en two anti-symmetric composite laminae. Because of the material anisotropy
and the anti-symmetric configuration, torsional vibration can be induced t
hrough the inplane strain actuated by the piezoelectric layer. The advantag
es of the motor are its magnetic field immunity, simple structure, easy mai
ntenance, low cost, and good low-speed performance. In this paper, the moto
r is considered to be a coupled dynamic system. The analytical model includ
es the longitudinal and torsional vibrations of the laminate and the rotati
ng motion of the rotor under action of contact forces. The analytical model
can predict the overall characteristics of the motor, including the modal
frequency and the response of motion of the laminate, the rotating speed of
the rotor, the input power, the output power, and the efficiency of the mo
tor. The effects of the initial compressive force, the applied voltage, the
moment of rotor inertia, and the frictional coefficient of the contact int
erface on the characteristics of the motor are simulated and discussed. A s
election of the numerical results from the analytical model is confirmed by
experimental data.