A Composite Ultrasonic Transducer with a Fractal Architecture

Ebrahem A. Algehyne, Anthony J. Mulholland

Research output: Other contribution

113 Downloads (Pure)

Abstract

To ensure the safe operation of many safety critical structures such as nuclear plants, aircraft and oil pipelines, non-destructive imaging is employed using piezoelectric ultrasonic transducers. These sensors typically operate at a single frequency due to the restrictions imposed on its resonant behaviour by the use of a single length scale in its design. To allow these transducers to transmit and receive more complex signals it would seem logical to use a range of length scales in the design so that a wide range of resonating frequencies will result. In this article we derive a mathematical model to predict the dynamics of an ultrasound transducer that achieves this range of length scales by adopting a fractal architecture. In fact, the device is modelled as a graph where the nodes represent segments of the piezoelectric and polymer materials. The electrical and mechanical fields that are contained within this graph are then expressed in terms of a finite element basis. The structure of the resulting discretised equations yields to a renormalisation methodology which is used to derive expressions for the non-dimensionalised electrical impedance and the transmission and reception sensitivities. A comparison with a homogenised (standard) design shows some benefits of these fractal designs.
Original languageEnglish
Media of outputResearch Report
PublisherUniversity of Strathclyde
Number of pages119
Publication statusUnpublished - 2015

Keywords

  • ultrasound
  • finite element method
  • fractal
  • renormalisation

Cite this