Title page for ETD etd-09122009-040516
|Type of Document
||Furrow, Keith W.
||Environmental effects on stitched RTM composites
||Master of Science
|Loos, Alfred C.
|Dillard, David A.
|Hyer, Michael W.
|Date of Defense
The effects of temperature and humidity cycling on mechanical properties of
AS4/3501-6 quasi-isotropic composites prepared from unstitched, Kevlar 29
stitched, and S-2 glass stitched uniweave fabric were determined. Data presented
include compression strengths and compression-compression fatigue results for
environmentally cycled and uncycled composites. Ten1perature cycling ranged
from 60°C to -55°C. The relative humidity varied between 95 percent at the high
temperature and a percent at the low temperature. Microcracks which were found
predominantly around individual stitches were recorded using photomicrographs
taken at the end of each cycling period. The glass stitched and Kevlar stitched
laminates showed significant microcracking before cycling. The unstitched
uniweave material developed microcracks only after cycling. The glass stitched
material had lower baseline compression strength than the unstitched and Kevlar
stitched materials. Temperature and humidity cycling reduced the static
compression strength of the unstitched and Kevlar stitched uniweave materials
nearly 10 percent. Under the same conditions the glass stitched uniweave
material lost 3 percent of its baseline strength. Combined temperature and
humidity cycling did not effect the fatigue properties of the uniweave materials
when the test specimens were dried to their original weights before testing.
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