Effects of Porosity on Delamination of Resin-Matrix Composites
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 20, 1990
- Accession Number
- ADA258817
Entities
People
- John F. Mandell
- William J. Tsai
Organizations
- Massachusetts Institute of Technology