Modeling and underwater characterization of cymbal transducers and arrays

2015 IEEE International Ultrasonics Symposium (IUS)

Tweedie³

et al. 2015

Abstract-This study builds on previous research by the authors, where the design of a miniaturized class IV transducer configuration and adaption for including an end-effector for use in biopsy are investigated. Device design has focused on the generation of displacement uniformity across the output surface of the transducer. This has the aim of maximizing device reliability and minimizing nonlinear responses that could adversely affect the performance of devices incorporating endeffectors. The devices investigated in this study, designed using finite element analysis, have been experimentally characterized to identify their impedance and resonant characteristics.

Section: Introductionmentioning

confidence: 99%

Ultrasonic biopsy needle based on the class IV flextensional configuration

Mathieson

2015 IEEE International Ultrasonics Symposium (IUS)

Tweedie³

et al. 2015

“…A hard PZT, Sonox P4 (CeramTec), was chosen as the piezoelectric driver. A thin layer of insulating epoxy resin (Eccobond, Ellsworth Adhesives Ltd), at a ratio of three parts resin to one part hardener, was used as the bonding agent, with insulating epoxy used because of the high bond strength compared to conductive epoxy resins (Zhang et al, 2001). Small solder spots were deposited on the top and bottom surfaces of the piezoceramic disk to ensure electrical connectivity with the electrodes.…”

Section: Transducer Fabricationmentioning

confidence: 99%

“…The cymbal transducer converts the small radial displacement amplitude of the driver disk, which is normally a piezoceramic such as lead zirconate titanate (PZT), into an amplified axial displacement (Zhang et al, 2001). The cymbal was developed in order to increase the generative force and operational displacement from that of an earlier moonie transducer (Silva et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Differential scanning calorimetry of superelastic Nitinol for tunable cymbal transducers

Journal of Intelligent Material Systems and Structures

Lucas

2015

Recent research has shown that estimations of the transformation temperatures of superelastic Nitinol using differential scanning calorimetry can be inaccurate, in part, due to the residual stress in the material. Superelastic Nitinol is selected as the end-cap material in a tunable cymbal transducer. The differential scanning calorimetry accuracy is initially probed by comparing transformation temperature measurements of cold-worked superelastic Nitinol with the same material after an annealing heat treatment, administered to relieve stresses from fabrication. The accuracy is further investigated through a study of the vibration response of the cymbal transducer, using electrical impedance measurements and laser Doppler vibrometry to demonstrate that the change in resonant frequencies can be correlated with the transformation temperatures of the Nitinol measured using differential scanning calorimetry. The results demonstrate that differential scanning calorimetry must be used with caution for superelastic Nitinol, and that an annealing heat treatment can allow subsequent use of differential scanning calorimetry to provide accurate transformation temperature data.

“…The layers were approximately 40μm thick. The reason that an insulating and not a conductive epoxy was chosen is that conductive epoxies tend to have lower bonding strength [7]. To ensure that electrical contact could be achieved between the end-cap flanges and the piezoceramic disc, a small solder spot was applied to each surface of the PZT.…”

Section: Cymbal Transducer Assemblymentioning

confidence: 99%

Vibration characterisation of cymbal transducers for power ultrasonic applications

Bejarano

Lucas

2012

J. Phys.: Conf. Ser.

School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK E-mail: f.bejarano-duran.1@research.gla.ac.uk Abstract. A Class V cymbal flextensional transducer is composed of a piezoceramic disc or ring sandwiched between two cymbal-shaped shell end-caps. These end-caps act as mechanical transformers to convert high impedance, low radial displacement of the piezoceramic into low impedance, large axial motion of the end-cap. The cymbal transducer was developed in the early 1990's at Penn State University, and is an improvement of the moonie transducer which has been in use since the 1980's. Despite the fact that cymbal transducers have been used in many fields, both as sensors and actuators, due to its physical limitations its use has been mainly at low power intensities. It is only very recently that its suitability for high amplitude and high power applications has been studied, and consequently implementation in this area of research remains undeveloped. This paper employs experimental modal analysis (EMA), vibration response measurements and electrical impedance measurements to characterise two variations of the cymbal transducer design, both aimed at incorporation in ultrasonic cutting devices. The transducers are fabricated using the commercial Eccobond 45LV epoxy adhesive as the bonding agent. The first cymbal transducer is of the classic design where the piezoceramic disc is bonded directly to the end-caps. The second cymbal transducer includes a metal ring bonded to the outer edge of the piezoceramic disc. The reason for the inclusion of this metal ring is to improve the mechanical coupling with the end-caps. This would therefore make this design particularly suitable for power ultrasonic applications, reducing the possibility of debonding at the higher ultrasonic amplitudes. The experimental results demonstrate that the second cymbal design is a significant improvement on the more classic design, allowing the transducer to operate at higher voltages and higher amplitudes, exhibiting a linear response over a practical power ultrasonic device driving voltage range. The results also show that the device can be accurately tuned using finite element modelling and that the cymbal exhibits a modal response as predicted by the finite element models.