Size effects in capped ceramic underwater sound projectors

Abstract

Absfracf-Cymbal transducers are small, thin Class V flextensional transducers. A single cymbal element consists of a piezoelectric disk sandwiched between two metal cymbal-shaped endcaps which serve as mechanical translormers, converting the low impedance, small extensional motion 01 the ceramic into high impedance, large flextensional motion 01 the endcap. A cymbal transducer element is very small, with a thin profile. A single element is characterized by high Q, low elficiency, and medium power capability. When comparing cymbals to other transducers, the designer should consider their use in large flexible, Iov cost arrays.This paper represents the work 01 eight researchers over a period 01 several years. The ellects 01 changes in materials and dimensions on the cymbal-type flextensional transducers, in-air and water-loaded, were examined experimentally and through finite-element-analysis (EEA).Experimental and FEA calculated results matched quite well. After gaining experience and confidence in the FEA models, extensive parametric studies were performed using FE.4 to investigate the size and material effects on cymbal transducer characteristics. The scaling lactor (i.e., overall size), endcap stiflness, and cavity design have the strongest influence on resonance frequency. Adjusting the dimensions and materials used lor drivers and endcaps provides a range in the fundamental flexural lrequency lrom aboul 5 to 150 kHz in water. These results also indicate trends that can be used to extend the ranges lurther. The sealing factor, cavity depth, and PZT thickness had the strongest ellects on the projectorlreceiver perlormance (TYWFFVS). Investigations are underway lo combine and optimize some of these parameters lor potentially significant improvements in bandwidth and efficiency.

Energy harvesting with a cymbal type piezoelectric transducer from low frequency compression

“…Previous studies have stated the importance of design parameters for Cymbal actuators and energy harvesters where crucial parameters include cavity size between the piezo material and the steel plates. Also diameter and thickness of the steel and the piezo element play an important role in the optimisation of energy harvesting [19,22,26]. Our design deviated from a traditional Cymbal actuator by having evenly curved convex steel plates compared to the more angular shaped design used in traditional Cymbal actuators.…”

“…Previously, Cymbal and Moonie type actuators have been widely studied and optimised for actuating purposes due to their ease of tailoring via dimension changes [19][20][21][22][23][24][25]. More recently, energy harvester designs and models of the Cymbal transducers have also been introduced.…”

Finite element analysis of Cymbal piezoelectric transducers for harvesting energy from asphalt pavement

“…6), 7) With the decreasing of the cavity depth h, cap thickness t c or PZT thickness t p , the first resonance frequency decreases because of decreased device stiffness. 6),7),10) The influence of cap material to the first resonance frequency was discussed by Newnham 7) and Wang.…”

“…6),7),10) The influence of cap material to the first resonance frequency was discussed by Newnham 7) and Wang. 8) FEA are used in those analysis based on ANSYS or ATILA code.…”

Finite Element Analysis of Underwater Cymbal Transducers With Large Displacement and Fast Response Time

“…Figure 4(a) shows the resonance spectrum of the cymbal transducer (with example of 0.25 mm end cap thickness, 0.3 mm cavity depth and 1.54 mm total thick). The first resonance peak at 28.53 kHz corresponding to the umbrella flexural mode of the metal caps, which mainly depends on the material and thickness of the end cap and the geometric parameter of the cavity beneath the end cap, is based on the following relation form S. Guo et al [17]:…”