Electromechanical coupling and output efficiency of piezoelectricbending actuators

摘要

Electromechanical coupling mechanisms in piezoelectric bendingnactuators are discussed in this paper based on the constitutivenequations of cantilever bimorph and unimorph actuators. Three actuatorncharacteristic parameters, (e.g., electromechanical couplingncoefficient, maximum energy transmission coefficient, and maximumnmechanical output energy) are discussed for cantilever bimorph andnunimorph actuators. In the case of the bimorph actuator, if the effectnof the bonding layer is negligible, these parameters are directlynrelated to the transverse coupling factor lest. In the case of thenunimorph actuator, these parameters also depend on the Young's modulusnand the thickness of the elastic layer. Maximum values for thesenparameters can be obtained by choosing proper thickness ratio andnYoung's modulus ratio of elastic and piezoelectric layers. Calculationnresults on four unimorph actuators indicate that the use of stiffernelastic material is preferred to increase electromechanical coupling andnoutput mechanical energy in unimorph actuators