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U.S. Department of Energy
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Influence of ply cracks on fracture strength of graphite/epoxy laminates at 76 K

Technical Report ·
OSTI ID:6488637
Quasi-isotropic laminates were fabricated from graphite/epoxy and quasi-statically loaded in tension at 76 K until fracture occurred. Fibers in 0-deg plies carry the largest portion of the tensile load; the weaker 90- and 45-deg plies crack at loads much lower than fracture strength. The effect of ply cracks on fracture of load-bearing 0-deg plies was examined to understand how defects affect laminate strength. A generalized plane-strain finite-element model was used to predict stress gradients in the 0-deg ply near the crack tip. Variations in residual stress caused by changes in temperature and absorbed moisture were included in the analysis.
Research Organization:
National Bureau of Standards, Boulder, CO (USA). Fracture and Deformation Div.
OSTI ID:
6488637
Report Number(s):
PB-85-205920
Country of Publication:
United States
Language:
English