Flextensional composite transducers: Designing, fabrication and application

Abstract

The design, fabrication and application of flextensional composite transducers are summarized in this study. The moonie and cymbal type flextensional transducer consist of a ceramic driving element sandwiched between two truncated conical metal or plastic endcaps. These transducers can be used as both sensors and actuators. Piezoelectric, electrostrictive and antiferroelectric-ferroelectric switching types of ceramic can be used as the driving element in either single layer or multilayer form. In the cymbal and moonie transducer designs, the flexibility and durability of metals and the driving power of the ceramic element are combined. Poled ferroelectric ceramics (Curie groups oem) possess three independent piezoelectric coefficients: d(31), d(33), and d(15). Each of the piezoelectric coefficients can be used as the driving element of a composite cymbal or moonie transducer. Cymbal transducers can also be fabricated from ring shaped ceramics sandwiched between truncated metal endcaps. Polarization and electric field directions of the samples can be altered systematically to make use of the three different piezoelectric coefficients as driving elements. The cymbal is a versatile performer. Desired actuation and sensing performance can be tailored by engineering the flexibility of the endcaps or changing the cavity dimensions beneath the endcaps. Possible design changes can be also investigated with FEM by using computational tools. Cymbal and moonie transducers can be used as hydrophones, acceleration sensors, positioners, and in many other applications.