Chiang Mai Journal of Science

A piezoelectric monolithic actuator was studied. It is a piezoelectric hollow cylinder coated with electrodes on both inner and outer surface. This actuator is called cylinder morph (Cmorph) in this paper due to the similarity in configuration and function as that of the conventional series bimorph. Compared with bimorph, higher resonant frequency and blocking force are available using the cylinder morph. It also reduces the interface problem in the bimorph actuator due to the monolithic structure and accordingly increases the reliability of the actuator. Both the longitudinal and bending displacement as a function of voltage in the static case were studied. It is found that in the lower electric field, the displacement varies linearly. In higher field, the displacement forms the butterfly shape. However, the bending deformation remains wider linear range than that of the longitudinal deformation. The resonant properties were also investigated. The displacement or vibration velocity depends on the frequency and driving voltage simultaneously. To obtain the maximum displacement or vibration velocity, the voltage and frequency should match well.