THE COMBINED EFFECTS OF CURING AND ENVIRONMENTAL EXPOSURE ON FRACTUREPROPERTIES OF WOVEN CARBON-EPOXY LAMINATES

This paper concerns a study of the combined effects of curing conditio ns and environmental exposure on the ultimate properties of two commer cial woven carbon/epoxy laminates. Curing parameters (heating rate and applied pressure) were varied so as to obtain six different condition s for each material. Moisture saturation was also achieved by exposing some of the cured samples to environmental conditions of 70-degrees-C and 95% relative humidity. Four different tests (tensile, impact, Mod e I and Mode II interlaminar fracture resistance) were therefore perfo rmed, and the results obtained on the different materials before and a fter moisture saturation compared. Neither curing pressure nor heating rate nor moisture absorption were observed to have any practical effe ct on tensile and impact properties. On the contrary, one noticeable e ffect was the interlaminar fracture resistance of the laminates. The r esults are discussed and interpreted in terms of damage formation and stress intensification mechanisms.