ZENNARO, M. ...et al., 2018. Parametric investigation of a transducer for guided wave applications. Presented at the 12th ECNDT 2018, Gothenburg, Sweden, 11-13th June.
The use of dry-coupled thickness-shear piezoelectric transducers for the generation of ultrasonic guided waves in Non Destructive Testing is well established in industry. The control of guided waves can be supported by designing transducers that achieve a uniform excitation over frequency and contact area. It is necessary to control the wave modes generated such that only modes with characteristics useful for inspection are transmitted and received. Recent research has identified the need to improve the ultrasonic performance in terms of amplitude and signal-to-noise ratio of guided waves via the miniaturization of the transducers. The influence of the geometry of the transducer on the generation of guided waves needs to be investigated. It is well known that the geometry of the transducers influences the normal modes of the ultrasonic transducers, which in turn can influence their ability to excited ultrasonic guided waves. However, the influence of transducer geometry on ultrasonic performance is still not
completely understood: mode coupling and the presence of satellite modes might be
detrimental for the generation of guided waves. These requirements drive the testing of design changes in terms of geometry and shape of the electrodes to improve the
ultrasonic performance of the aforementioned transducers. The transducer is analysed
both numerically (by Finite Element Analysis) and experimentally (with Laser
Vibrometry) to offer a characterisation of existing piezoelectric elements. It is shown
that a change in the actuation area of the transducer leads to a significant difference in the ultrasonic output.
This is an Open Access Article. It is published under the Creative Commons Attribution 4.0 Unported Licence (CC BY-NC). Full details of this licence are available at: http://creativecommons.org/licenses/b-nc/4.0/
The corresponding author would like to acknowledge the financial support of Lloyd’s
Registered Foundation, Loughborough University and TWI.