Effect of geometry on the characteristics of a drum actuator

This study presents a large displacement, piezoceramic and metal composite-based actuator, named drum piezoceramic-actuator. The drum actuator consists of a short, thick-walled steel cylinder sandwiched by two thin composite disks, which are fabricated from a brass disk bonded with one piezoceramic disk. The piezoceramic disk polarized in its thickness direction is of a large diameter to thickness ratio, thus, produces a large radial displacement under an applied voltage in the thickness direction, and consequently results in a large transverse deflection of the composite disks in the drum. Some original results are obtained in the drums with the geometrical changes in the short, thick-walled steel cylinder. The drum (outer diameter: 12.0 mm) demonstrates displacement output 7 times as large as that of a cymbal actuator with the same ceramic material and comparable dimensions under the same DC driving voltage of 78 V. The effective piezoelectric charge coefficient d33 of the drum is measured and is about 3 times as large as that reported for the cymbal. The drums also showed first resonance frequency of the transducer from 15.68 to 32.57 kHz and faster response time of about tens microseconds which are mainly based on the dimensions of the short, thick-walled steel cylinder.