ACOUSTIC
EMISSION & NDT SCIENTIFIC PUBLICATIONS
Application of a Fibre-Optic Acoustic Emission Sensor to the
Fatigue Testing of Wind Turbine Blades
Journal of Smart Materials and Structures (submitted)
C. Doyle,
C. Tuck, R. Chen, G. F. Fernando, G. Zheng, T. Liu,
P Joosse, D R V van Delft, A G Dutton, M
Blanch, P Vionis, V. Kolovos,
A
Anastassopoulos, D Kouroussis,
T Kossivas, J. ter Laak,
T. P.
Philippidis, Y. G. Kolaxis, A. Proust
The detection of
acoustic emission from composites can help to diagnose the condition
of a structure made from such materials. Conventionally, monitoring
is performed by surface-mounted piezoelectric transducers. These
transducers are relatively bulky and can be susceptible to
electrical interference, drawbacks which could be overcome by using
fibre-optic sensors if they had adequate sensitivity.
This paper presents
a new type of acoustic emission sensor, based on a fused tapered 2 x
2 coupler. Sensors were mounted on the surface of a glass-epoxy
panel, excited with simulated AE signals and their output was
compared to that of a commercial piezoelectric transducer. The
amplitude of the fibre-optic sensor response was only 20 dB less and
a signal-to-noise ratio of 45 dB was achieved. Devices have been
integrated into a commercial AE instrumentation system and used for
acoustic emission monitoring of a glass-polyester composite coupon
during a tensile test. Data generated by a fibre-optic sensor during
a fatigue test on a small wind turbine blade, made of the same
material, are also presented.