Evaluation of the Adhesive Bonding Processes Used in Helicopter Manufacture. Part 4. Nondestructive Inspection of Adhesive Bonds Using Holographic Techniques.
PICATINNY ARSENAL DOVER N J
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ANELS, HONEYCOMB CORES, LASERS, LAMINATES, DEGRADATIONHOLOGRAPHYDouble exposure holographic techniques are used to nondestructively examine the condition of adhesive bonds in honeycomb panels. The panels are subjected to a high humidity environment which causes adhesive degradation. Periodically the panels are holographically examined. Observation of the fringe patterns reveals that the gradual degradation of the bond can be readily seen as the humidity attacks the adhesive starting with the outer edges, working its way inward. Two different prebonding preparation techniques are examined. The different rates of attack on the two types of panels are clearly recorded by the holographic technique. Since the panels were in no way destroyed or affected, these experiments give strong evidence of the power of optical holography as a nondestructive test which not only indicates disbonds but may even relate to bond strength or quality. Author-PL
- Laminates and Composite Materials
- Test Facilities, Equipment and Methods