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Vibration Characteristics of Stepped Thickness Circular Cylindrical Piezoelectric Shells for Ultrasound Amplifications

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Thesis is embargoed until 18 October 2025(13.03 MB)

Date

2018

Authors

Supervisor

Al-Jumaily, Ahmed

Item type

Thesis

Degree name

Doctor of Philosophy

Journal Title

Journal ISSN

Volume Title

Publisher

Auckland University of Technology

Abstract

This research investigates the vibration characteristics of stepped-thickness cylindrical shells with a specific application to ultrasound power amplifications for water particle disintegration. One of the main purposes is to develop an ultrasound transducer with large acoustic power and relatively small power consumption. Stepped-thickness variations are introduced to develop alternative thick-thin regions and then large localized vibration amplitudes within the transducer to maximise the acoustic field for the same driving power input. The curvature of the cylindrical shell combined with piezoelectricity and the localized vibration constructive interferences at the centreline of the transducer work together to enhance the resultant focused acoustic field. This work led to a transducer which generates an acoustic field with approximately double acoustic pressure for the same power supply as compared with a uniform-thickness transducer. Computer simulation as well as experimental investigation are used to optimise the performance of this transducer. The transducer was successfully used to disintegrate water droplets to smaller sizes. It is anticipated that this finding will be implemented to disintegrate particles for various applications including biomedical humidification for lung supportive devices.

Description

Keywords

Vibration characteristics, Stepped thickness, Piezoelectric shells, Ultrasound amplifications

Source

DOI

Publisher's version

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Permanent link

https://hdl.handle.net/10292/11884

Collections

Doctoral Theses