Through-the-thickness tension strength of 3-D braided composites
- North Carolina A and T State Univ., Greensboro, NC (United States)
Three-dimensional [0{sub 12k}/{+-}{beta}{sub 12k}]{sub 46% axial} braided, and equal thickness and fiber orientation (0/{+-}45){sub 47% axial} laminated composite L-beam specimens were fabricated and tested for through-the-thickness strength. The braided specimens were fabricated with BASF G30-500, 12k graphite fiber tows and Tactix 123 matrix and the laminated specimens were fabricated with AS4 graphite fibers and 3501-6 matrix. A simple curved beam equation was used to calculate the through-the-thickness strength of composites from the test data. The average strength of braided, equivalent laminate, and unidirectional composites were found to be 24.2, 28.8, and 40.9 MPa, respectively. The strengths of braided and equivalent laminate composites were nearly equal within the data scatter. Through-the-thickness strength of composites was found to be a matrix dependent property. The lower strength of braided and the equivalent laminated composites could be attributable to the stress concentration arising from the fiber termination at the edges. Failure modes in braided composites were matrix cracks, tow cracks, and tow separation; whereas in laminates they were delaminations and ply-cracks. Reduction of size of resin pockets in braided composites may improve the through-the-thickness strength.
- OSTI ID:
- 89868
- Report Number(s):
- CONF-9409291-; ISBN 1-56676-220-0; TRN: IM9536%%298
- Resource Relation:
- Conference: 9. technical conference of the American Society for Composites, Newark, DE (United States), 20-22 Sep 1994; Other Information: PBD: 1994; Related Information: Is Part Of Proceedings of the American Society for Composites: Ninth technical conference; PB: 1319 p.
- Country of Publication:
- United States
- Language:
- English
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