FATIGUE CHARACTERISTICS OF GRAPHITE-EPOXY LAMINATES UNDER COMPRESSION LOADING

A limited number of tests were performed for R equals 0, minus infinity , and minus 1 loading to determine the significance of the compression loading and to investigate the failure mechanism. These tests indicated a significant life reduction for both R equals minus infinity and R equals minus 1 loading with respect to tension-tension loading, with the life reduction for R equals minus 1 being greater. The mechanism of failure appeared to be local progressive fatigue failure of the matrix near a stress riser, thus causing fiber split, progressive delamination, and resulting fiber buckling, which then precipitates laminate failure.