Accession Number : ADA258817


Title :   Effects of Porosity on Delamination of Resin-Matrix Composites


Descriptive Note : Final rept. Jun 1984-Jun 1987


Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MATERIALS SCIENCE AND ENGINEERING


Personal Author(s) : Mandell, John F ; Tsai, William J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a258817.pdf


Report Date : 20 Apr 1990


Pagination or Media Count : 162


Abstract : The effect of porosity and moisture content on delamination resistance of unidirectional AS4/3501-6 graphite/epoxy composite was investigated. The results show that the effects of porosity on delamination resistance depend strongly on the mode of loading. Mode I static G sub Ic levels can be significantly increased at high porosity due to the formation of multiple crack fronts, while G sub IIc is almost independent of porosity level. Moisture saturation increases the amount of fiber bridging in Mode I, and so increases G sub Ic, particularly at low porosity; G sub IIc is reduced slightly by moisture saturation. In fatigue, the increases in G sub Ic from high porosity and moisture saturation are offset by a lower fatigue crack growth exponent, so that the crack growth rates approach those of the dry control at low cyclic G, levels. Mode II fatigue crack growth was not strongly affected by porosity level, but the crack growth exponent was lower under wet, high porosity conditions.


Descriptors :   *POROSITY , *GRAPHITE EPOXY COMPOSITES , RESISTANCE , CRACKS , GRAPHITE , MOISTURE CONTENT , SHEAR STRENGTH , FIBERS , FATIGUE(MECHANICS) , EPOXY COMPOSITES , STATICS , DELAMINATION , COMPOSITE MATERIALS , SATURATION


Subject Categories : Laminates and Composite Materials


Distribution Statement : APPROVED FOR PUBLIC RELEASE