An analysis is presented for the strength in three-point flexural loading of a rectangular unidirectional composite beam reinforced with Keviar®1 49 aramid fibers. The material behavior is assumed to be linearly elastic in tension and elastic-perfectly plastic in compression. The statistical effects of volume and stress distribution on tensile strength are included in the model. The predicted strength agrees reasonably well with experimental data.
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References
1.
J.H. Greenwood and P.G. Rose, "Compressive Behavior of Kevlar® 49 Fibres and Composites," J. Materials Science, Vol. 9 (1974), p. 1809.
2.
M. Biot, Mechanics of Incremental Deformations, John Wiley & Sons, Inc., New York1965.
3.
C. Zweben, W.W. Smith, and M.W. Wardle, "Test Methods for Fiber Tensile Strength, Composite Flexural Modulus and Properties of Fabric-Reinforced Laminates," Fifth ASTM Conference on Composite Materials: Testing and Design, New Orleans, March 1978. To appear in forthcoming ASTM Special Technology Publication.
4.
W. Weibull, "A Statistical Theory of the Strength of Materials," Ing Vetenskaps Akad. Handl. (Royal Swedish Inst. Eng. Research Proc.), NR151, 1939.
5.
W. Weibull, "A Statistical Distribution Function of Wide Applicability," J. Applied Mechanics, (1951).
6.
H. Leon Harter, "A Survey of the Literature on the Size Effect on Material Strength ," AFFDL-TR-77-11, U.S. Air Force Flight Dynamics Laboratory , April 1977.
7.
J.A. Kies, "The Strength of Glass Fibers and the Failure of Filament Wound Pressure Vessels," NRL Report 6034 Naval Research Laboratory, Washington, D.C., 1963.
8.
L.A. Riedinger, M.H. Kural, and G.W. Reed, Jr., "Evaluation of the Potential Structural Performance of Composites," Mechanics of Composite Materials, Wendt, F. W., Liebowitz, H., and Perrone, N., eds., Pergamon Press, Oxford, ( 1970), p. 481.
9.
C. Zweben, "Tensile Failure Analysis of Fibrous Composites," AIAA J , Vol. 6, (1968), p. 2325.
10.
B.E. Kaminski , "NARMCO 5208/T300 - A Graphite-Epoxy System Engineered for High-Performance Aircraft Structures," Proc. 5th National SAMPE Tech. Conf., New York, October 1972.
11.
R.E. Bullock , "Strength Ratios of Composite Materials in Flexure and in Tension," J. Composite Materials, Vol. 8, (1974), p. 200.
12.
N.A. Weil, and I.M. Daniel, "Analysis of Fracture Probabilities in Non-Uniformly Stressed Brittle Materials," J. Amer Ceram. Soc , Vol. 47 (1964), p. 268.
13.
Kulkarni, S.V. , Rice, J.S. and Rosen, B.W., "An Investigation of the Compressive Strength of "Kevlar"49/Epoxy Composites", Composites, Vol. 6, September 1975 , pp 217-225.