| ABSTRACT: | A FLEXIBLE PHASED ARRAY TRANSDUCER FOR CONTACT EXAMINATION OF
COMPONENT WITH COMPLEX GEOMETRY
O. Casula1, O. Roy2 ,G. Cattiaux3
1CEA, LIST / DECS / SISC, CEA Saclay, France 2M2M, Saint Remy, France, 3IRSN, Fontenay Aux
Roses, France
Most of Industrial Non Destructive Testing are carried out in contact due to their environment. As an
example, the inspection of cooling circuit components of French pressurized water reactors is mainly
performed with contact ultrasonic transducers. The realistic profiles of these components involve the
solid wedge is not matched to the irregular surface and to the 3D-profile of components (nozzle,
elbow). Indeed, an irregular coupling layer located between the wedge and the surface lead to loss of
sensitivity and beam distortions. These two phenomena contribute to degrade inspection
performances.
To improve such inspections, a new concept of contact “smart phased array transducer” has been
developed with the support of the French safety authorities (IRSN).
The phased array radiating surface is flexible to fit a complex profile and to minimize the coupling
layer. Both elements composing the phased array are mechanically assembled in order to realise an
articulated structure with a 15 mm minimum curve shape.
A profilometer embedded in the transducer allows to compute in real-time the optimised delay laws to
compensate the profile distortions. Those delay laws are transmitted to the real-time UT acquisition
system which applies them to the elements.
This self-adaptive process preserves, during the scanning, the features of the focussed beam
(orientation and focal depth).
Inspections of realistic irregular profiles of mock-ups, including artificial defects, have been carried
out, to estimate the enhancement performances of the "smart phased array transducer" compared to
conventional contact probes.
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