Modélisation de moteurs piézoélectriques

Abstract
This paper deals with to the theoretical analysis of two kinds of piezoelectric motors in order to determine for each of them the dedicated electromechanical coupling factors (EMC factors) which are important choice criteria for the energy conversion inside the piezoceramic materials. The first motor is based on the non-symmetrical radial motion of a piezoelectric disk. The second type of motor uses Lamb wave propagation inside a piezoceramic disk. The EMC factor determination implies the calculation of the displacements, stresses and electrical impedance of each type of motors. As a result, the rotor in contact with the motor stator rotates because an elliptic motion occurs on the surface situated between the rotor and the stator. The analytical modellings show that the energy conversion is characterized by one EMC factor for the first type of motor and two EMC factors for the second type. However, in each case, two kind of waves are involved : longitudinal and shear waves. These results are consistent with the constitutive piezoelectric equations used for each of the considered modes.