| Abstract | Automatic fiber placement (AFP) is an innovative method for fabricating monolithic large-scale composite structures, such as the big and long barrels that can be assembled to make the fuselage of an airplane. Laser-ultrasonics and laser tapping, which use lasers for generation and detection of ultrasound, are established inspection techniques that are very efficient for detecting flaws (delaminations, disbonds) in complex shape composite structures. A laser-ultrasonic system with a configuration well adapted for the inspection of these big barrel structures was designed, built and installed at the National Research Council of Canada facility, located at Mirabel, Qc, adjacent to composite manufacturing operations. The laser-ultrasonic system is mounted on a long cantilever structure that is inserted into the fuselage. The probing head includes a rotating mirror assembly allowing 360° and one meter wide or more scanning of the whole internal wall of the barrel. The system can also inspect the external wall, when the barrel is mounted on carriage allowing rotation around its axis, as well as various smaller complex shape parts. This inspection system can be operated in both laser-ultrasonic and laser-tapping modes, the latter being particularly useful for honeycombs. A detailed description of the system is presented. |
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