End driven bender transducer

Abstract

Piezoelectric bender transducers provide a low frequency resonance response from a simple compact structure. They often take the form of bilaminar or trilaminar piezoelectric ceramic discs or beams. The bending occurs in the piezoelectric ceramic discs or beams mounted on a simple support with the piezoelectric ceramic layers operating in phase oppositions creating the bending. The low tensile strength of the ceramic under hydrostatic pressure can be an issue with this type of transducer. We present here an alternative means for bender transduction in which the bending beam is a higher strength material, such as a metal, and the piezoelectric active section is now the end support, replacing the simple support of the legacy benders. The end supporting piezoelectric material is driven with the inner section operating out of phase with the outer section causing the bender beam to rotate on this piezoelectric simple support. In this design the major bending occurs in a higher tensile strength material capable of operating under high hydrostatic pressures. We present low frequency designs optimized for operation when end-driven by various piezoelectric materials. Typical transducer parameters and metrics are presented along with the transmitting response.