COMPOSITE PIEZOELECTRIC TRANSDUCER WITH TRUNCATED CONICAL ENDCAPS CYMBAL

This paper presents original results obtained in the development of th e moonie-type transducers for actuator applications. The moonie-type a ctuators fill the gap between multilayer and bimorph actuators, but it s position-dependent displacement and low generative force are unaccep table for certain applications. The moonie transducers were modified s ystematically by using finite element analysis combined with experimen tal techniques. A new transducer design, named ''cymbal transducer'', was developed with larger displacement, larger generative forces, and more cost-effective manufacturing. The cymbal, transducers consist of a cylindrical ceramic element sandwiched between two truncated conical metal endcaps and can be used as both sensors and actuators. The cymb al actuator exhibits almost 40 times higher displacement than the same size of ceramic element. Effective piezoelectric charge coefficient, Eff. d(33), of cymbal is roughly 40 times higher than PZT itself.