|
Wavenumber Spiral FSAT:
PVDF prototype testing The
proposed transducer concept can be employed in a variety of SHM scenarios.
Applications include localization of broadband acoustic sources or scattering
events from a single time trace. Testing of an inkjet-printed PVDF prototype of the FSAT has
been performed through source localization experiments. |
|||
|
|
|||
|
Experimental
setup Fig. 1 illustrates the experimental setup
used for validation. The FSAT is bonded at the center of a 0.82mm-thick
Aluminum plate. 5mm-diameter PZT actuators are attached to the plate at
different positions through Sonotech shear-couplant gel. Broadband excitation
of the PZTs within the active frequency range of the FSAT, i.e. [50, 350] kHz
for the considered waveguide thickness, is provided by a Panametrics-NDT
5058PR pulser. The sensor response is recorded by a Tektronix TDS2024
oscilloscope controlled via GPIB by a Matlab graphical user interface (GUI),
which also includes the imaging
software, as shown in Fig. 2. |
|
||
|
|
|||
|
Fig. 2: Matlab GUI for FSAT signal
recording and processing. |
|||
|
Results The directional filtering
performed by the sensor is visible from Movie 1, which shows the warped FSAT output and associated spectrum obtained
by GW sensor recording upon sequential activation of a PZT source at
different locations. Expected peak frequencies depending on the incoming wave
direction are superimposed to the signal FFT. Corresponding imaging results
show successful localization of the active source, as can be seen from Movie 2. This preliminary
experimental validation demonstrates effectiveness of the FSAT concept,
feasibility and robustness of the sensing operation, which provides drastic
reduction of hardware resources required for imaging of 2D areas, i.e. one or
two channels compared to typical 16- to 64-channel phased arrays. Different
piezoelectric substrates are currently under investigation to provide
enhanced sensing as well as actuation capabilities. |
|||
|
Movie 1: Warped FSAT output and associated FFT
for sequentially activated PZT sources. |
|||
|
Movie 2: FSAT-based imaging of sequentially
activated PZT sources, whose true location is indicated by ‘+’ marker. |
|||
|
|
|||
|
Georgia
Institute of Technology – Contact Us: |
|||
|
Massimo Ruzzane Emanuele Baravelli Matteo
Senesi |
|||
