Originally Posted by
Paul Cantrell
I have a question about composites, specifically I wonder about the state of the art in NDT?
Film radiography (X-ray) is be used to verify fiber orientation in a completed carbon fiber part, provided there is a representative radiopaque tracer present, such as fiberglass.
Radiography, either film type or real time fluoroscopy, has been known to find bond voids in a bonded structure, provided the adhesive is of sufficient radiopacity. That one was quite a surprise!
Automated vision systems are used to optically verify the fiber orientation of individual plies during layup.
Rap tests, or some variation thereof, which determine the natural frequency of a structure, will likely be used at some point in production and repair, if not being done now. The information could be used to verify the correct assembly was performed, the correct stiffness and mass distribution was achieved (for balance purposes), and to assess possible degradation in blades being repaired.
DS