Senior research engineer, Babcock & Wilcox Co., Alliance Research Center, Alliance, Ohio
Pages: 9 Published: Jan 1975
Crazing has recently become of interest in composite materials having organic matrices, and the development of crazes has been suggested as a failure criterion in the fatigue testing of susceptible composites.
This paper reports the results of an experiment to find a practical means of detecting and monitoring the development of crazing during fatigue testing of fiber-reinforced epoxy matrix composite materials. A specimen of such material was strain-gaged with one 2-in.-long (0.051 m) foil gage, and with thirty 2/100-in.-long (0.508 mm) gages. The apparent strain of each gage was monitored during displacement control tension-tension fatigue testing.
The experimental results demonstrated that the maximum difference between apparent strains as measured by the small strain gages provided a sensitive means of detecting crazing. It was concluded that thirty small strain gages with appropriate instrumentation could provide a practical means of automatically detecting crazing during such fatigue tests of composite materials.
composite materials, epoxy laminates, fiberglass reinforced plastics, reinforced plastics, fiber composites, tests, mechanical tests, tension tests, fatigue (materials), fatigue tests, failure, crazing, detection, strain gages
Paper ID: STP32322S