Fabrication and high durability of functionally graded piezoelectric bending actuators

A new type of functionally graded (FG) piezoelectric bending actuator was proposed by the present authors in their former study and the advantage of the new actuator over the traditional bimorph and unimorph actuators in internal stress distribution was illustrated by simulation results. In this study, the fabrication process of FG piezoelectric bending actuators is developed and the characteristics of the fabricated actuators are investigated. The material compositions with different dielectric and piezoelectric constants were selected from the Pb(Ni1/3Nb2/3)O-3-PbZrO3-PbTiO3 family and used as the four layers in the new FG piezoelectric actuator. The piezoelectric constant and dielectric constant were graded oppositely in the thickness direction. The durability of the fabricated FG piezoelectric actuators was measured in a vibration test and compared with that of the traditional bimorph actuator to evaluate the improvement of performance. The results show that the durability of the FG piezoelectric actuators is much higher than that of the bimorph actuator.