Tests were performed to assess the effects of processing temperature and laminate layup on matrix cracking. Twelve inches long and one inch wide cross-ply and angle ply coupons made of Fiberite T300/976 graphite/epoxy were tested. Coupons of different layup were cured and postcured at different temperatures. The number of cracks was determined from X-ray pictures. The results showed that the number of cracks depends directly on the maximum temperature reached during processing, and is minimized when the 900 plies are dispersed (not stacked together) in the laminate.
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References
1.
1. Groves, S. E., C. E. Harris, A. L. Highsmith, D. H. Allen and R. G. Norvell. 1987. "An Experimental and Analytical Treatment of Matrix Cracking in Cross-Ply Laminates,"Experimental Mechanics, 27:73-79.
2.
2. Flaggs, D. L.1985. "Prediction of Tensile Matrix Failure in Composite Laminates,"Journal of Composite Materials, 19:29-50.
3.
3. Hashin, Z.1985. "Analysis of Cracked Laminates: A Variational Approach,"Mechanics of Materials, 4:121-136.
4.
4. Liu, S. and J. A. Nairn. 1992. "The Formation and Propagation of Matrix Microcracks in Cross- Ply Laminates during Static Loading,"Journal of Reinforced Plastics and Composites, 11:158-178.
5.
5. Shahid, I. and F. K. Chang. 1994. "A Damage-Mechanism Based Fracture Model for Laminated Composites Subjected to Multiple In-Plane Loads-I. Model Development,"Journal of Composite Materials, in print.
6.
6. Griffin, O. H., Jr. and J. C. Roberts. 1988. "Numerical/Experimental Correlation of Three- Dimensional Thermal Stress Distributions in Graphite/Epoxy Laminates,"Journal of Composite Materials, 17:539-548.
7.
7. Griffin, O. H., Jr.1988. "Three-Dimensional Thermal Stresses in Angle-Ply Composite Laminates,"Journal of Composite Materials, 22:53-70.
8.
8. Wu, C. H. and T. R. Tauchert. 1980. "Thermoelastic Analysis of Laminated Plates. 1: Symmetric Specially Orthotropic Laminates,"Journal of Thermal Stresses, 3:247-259.
9.
9. Dusi, M. R., W. I. Lee, P. R. Ciriscioli and G. S. Springer1987. "Cure Kinetics and Viscosity of Fiberite 976 Resin,"Journal of Composite Materials, 21:243-261.
10.
10. Loos, A. C. and G. S. Springer. 1983. "Curing of Epoxy Matrix Composites,"Journal of Composite Materials, 17:135-169.
