This study examines the phenomena of damage development and the associated stiffness reductions and ultimate failure for crossply graphite/epoxy laminates under monotonic loading. The damage state is related to the measured and predicted stiffness reductions and ultimate strength of the laminates. Experimental data show that the predominant form of damage in all laminates was transverse matrix cracking monitored by X-radiography. The crack density variation obtained from the radiographs corresponds closely with the characteristic features of the stress-strain curves. No longitudinal matrix cracking or delamination was detected. This was confirmed by stress analysis showing that at failure the transverse stress in the 0-deg plies was still below the transverse strength of the material. Ultimate failure was governed by the ultimate tensile strain in the 0-deg plies with any small variations attributed to residual stresses, statistical scatter and local strain concentrations.
|Original language||English (US)|
|Number of pages||4|
|Journal||Annual Technical Conference - Society of Plastics Engineers|
|State||Published - Dec 1 1989|
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