Piezoelectric ceramic/metal bending actuators with functionally graded microstructures

As a model study for bending actuators with functionally graded microstructures (FGM), platinum (Pt)-dispersed lead zirconate titanate (PZT) piezoelectric ceramic composites and laminated PZT/Pt bimorph actuators were fabricated by powder processing. The electrically induced deflections of the graded bimorph actuators were evaluated and compared with theoretically predicted values. The present study demonstrated that the FGM actuators suffer from low stress concentrations during electric actuation, while exhibiting bending displacements equal to that of the conventional non-FGM actuators. It was also found that the actuation property of an FGM actuator is dependent on its compositional distribution through the thickness, suggesting that design is valid and important for the development of FGM piezoelectric actuators.