Acoustic Emission in Fiber Reinforced Composites.
NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA AIR VEHICLE TECHNOLOGY DEPT
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Acoustic emission monitoring offers a simple means of studying the effects that microscopic defects have on composites, since the emissions are a direct result of material deformations. This dissertation examines the research and development applications that acoustic emission monitoring has for fiber reinforced composites. Specific emphasis is placed upon obtaining information from fundamental failure processes, but practical engineering applications are reviewed as well, including fatigue crack detection and structural integrity evaluation. Basic principles of the phenomenon are covered, including the generation of emissions, the propagation of stress waves through materials, the production of electrical signals from mechanical stress waves, and signal processing to obtain data on microscopic sample deformations. An experiment is discussed which indicates that six-ply, 0 degree, plus or minus 45 degree carbon fiber reinforced plastic can be successfully monitored for incipient failure.
- Laminates and Composite Materials