Ring type uni/bimorph piezoelectric actuators

This paper presents a ring type piezoelectric actuator that combines a ringshaped piezoelectric component with a thin metal disc. In this actuator, the ring-shaped piezoelectric ceramic produces a radial contraction or expansion, and results in a large flexural displacement of the center of the metal disc. When the PZT ring under the metal disc contracts, the unbounded portion at the center of the disc is permitted to bend with a larger curve in positive (upper) direction. Both experimental results and FEM analysis support the new concept and confirm that the ring type uni/bimorph (ring-morph) configuration has a larger displacement output than that of conventional disc type uni/bimorph actuators with comparable dimensions.