ACOUSTIC
EMISSION & NDT SCIENTIFIC PUBLICATIONS
Acoustic Emission Monitoring During Certification Testing of
Wind Turbine Blades
European Wind Energy Conference, Copenhagen,
Denmark, 2-6 July 2001
A G Dutton, M Blanch, P Vionis, D Lekou, D R
V van Delft, P Joosse,
A Anastassopoulos, D Kouroussis,
T Kossivas,
T Philippidis, Y Kolaxis,
G Fernando,
A Proust
Wind
turbine blade certification tests, comprising a static test,
a fatigue test, and finally a residual strength test, often
involve sudden audible cracking sounds from somewhere within
the blade, without the operators being able to locate the
noise source, or to determine whether damage (minor or
major) has occurred. A current EC-funded research project is
looking at the possibility of using acoustic emission (AE)
monitoring during testing of fibre composite blades to
detect such events and assess the blade condition. AE can
both locate and characterise damage processes in blades,
starting with non-audible signals occurring due to damage
propagation at relatively low loads. The test methodology is
discussed in the context of the blade certification
procedure and results presented from a series of static and
fatigue blade tests to failure in the laboratory. Inferences
are drawn about small differences in the manufacture of the
nominally identical blades and conclusions presented for the
application of the methodology.