Stress dependence of ultrasonic velocity in unidirectional graphite/epoxy composites for longitudinal waves propagating along the direction of stressMeasurements of stress-induced velocity changes for propagation along the direction of applied stress in graphite/epoxy composites are presented. A linear relation between normalized velocity shift and stress is demonstrated for propagation and stress direction perpendicular to the fiber direction. The ratio of the SAC to the elastic compliance for this loading direction was assessed and found to have a value similar to that of numerous other materials which have very different linear elastic properties. Measurements with stress and propagation along the fibers yielded unusual behavior; the curves were very nonlinear and even shifted direction at higher loads.
Document ID
19920031024
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Prosser, William H. (NASA Langley Research Center Hampton, VA, United States)