Title :
Flexible ultrasonic transducers incorporating piezoelectric fibres
Author :
Harvey, Gerald ; Gachagan, Anthony ; Mackersie, John W. ; McCunnie, Thomas ; Banks, Robert
Author_Institution :
Rolls-Royce plc, East Kilbride, UK
fDate :
9/1/2009 12:00:00 AM
Abstract :
It is possible to produce a high-performance, flexible 1-3 connectivity piezoelectric ceramic composite with conventional methods but the process is difficult and time-consuming. Extensive finite element modeling was used to design a piezocomposite structure which incorporated randomly positioned piezoceramic fibers in a polymer matrix. Simple manufacturing techniques were developed which resulted in the production of large numbers of fully populated fiber composites that offered performance comparable with a conventional 1-3 piezocomposite. A modified process facilitated the production of efficient fiber piezocomposite elements separated by polymer channels which conformed to a highly flexible (13 mm radius of curvature), 2-D matrix array configuration. This arrangement has been termed a Composite Element Composite Array Transducer, or CECAT. These devices were evaluated in terms of their impedance spectra, pulse-echo response, and surface displacement characteristics. The random piezoceramic fiber arrangements showed comparable sensitivity and bandwidth to periodic devices while minimizing the parasitic interpillar modes associated with periodic structures. Investigations have indicated that CECAT arrays constructed with 250 mum diameter fibers can be operated at frequencies of up to 3 MHz and transducers incorporating 10 mum diameter fibers can extend the frequency range above 6 MHz. Conversely, improved low-frequency devices can be produced with taller pillars than possible with conventional manufacturing techniques.
Keywords :
acoustic impedance; fibre reinforced composites; filled polymers; finite element analysis; piezoceramics; ultrasonic transducer arrays; 1-3 connectivity; 2D matrix array configuration; CECAT array; Composite Element Composite Array Transducer; finite element modeling; flexible ultrasonic transducers; impedance spectra; piezoelectric ceramic composite; piezoelectric fibres; polymer matrix; pulse-echo response; surface displacement characteristics; Ceramics; Finite element methods; Frequency; Manufacturing; Optical fiber devices; Piezoelectric materials; Polymers; Production; Surface impedance; Ultrasonic transducers;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
DOI :
10.1109/TUFFC.2009.1276