On the Application of the Maximum Stress Failure Criterion to Off-Axis and Angle-Ply Laminates

Abstract

It has been commonly reported that the maximum stress failure theory predicts that the tensile stress (applied at 0°) needed to produce fiber failure in low angle off-axis (α) and angle-ply (±α) tensile specimens exceeds the unidirectional tensile strength. We point out that for small angles the usual strength analysis of the off-axis tensile specimen does not employ the stress state found in the region where fracture is ex pected to initiate. Consequently, the customary analysis is suspect. We also show, con trary to previously published results, that classical plate theory used in conjunction with the maximum stress failure criterion does indeed predict that the strength of an angle-ply laminate decreases with increasing angle when fiber failure dominates.

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References

Burke, R.C. , "Standard Failure Criteria Needed for Advanced Composites," Astronautics and Aeronautics, p. 58 (June 1983).

Stowell, E.Z. and Liu, T.S. , "On the Mechanical Behavior of Fibre-Reinforced Crystalline Materials," J. Mech. Phys. Solids , Vol. 9, p. 242 (1961).

Kelly, A. and Davies, G.J. , "The Principles of the Fiber Reinforcement of Metals," Metallurgical Reviews, Vol. 10, p. 1 (1965).

Knappe, W. and Schneider, W. , "The Role of Failure Criteria in the Fracture Analysis of Fibre-Matrix Composites," Deformation and Fracture of High Polymers , ed. H. H. Kausch, J. A. Hassell and R. I. Jaffee, Plenum Press, New York, pp. 543-556 (1973).

Hull, D. , An Introduction to Composite Materials, Cambridge University Press (1981 ).

Tsai, S.W. , "Strength Theories of Filamentory Structures," Fundamental Aspects of Fiber Reinforced Plastic Composites, Schwartz, R. T. and Schwartz, H. S., ed., Interscience, John Wiley (1968).

Jones, R.M. , Mechanics of Composite Materials, Scripta Book Co. (1975).

Piggott, M.R. , Load-Bearing Fibre Composites, Pergamon Press (1980).

Broutman, J. , "Mechanical Behavior of Fiber Reinforced Plastics," Composite Engineering Laminates, ed. A. G. H. Dietz, MIT Press (1969).

10.

Roode, F. , "Strength Criteria for Composite Materials (A Literature Survey)," NASA TM-77001 (December 1982).

11.

Pagano, N.J. and Halpin, J.C. , "Influence of End Constraint in the Testing of Anisotropic Bodies," J. Comp. Matls. , Vol. 2, p. 18(1968).

12.

Rizzo, R.R. , "More on the Influence of End Constraints on Off-Axis Tensile Tests," J. Comp. Matls., Vol. 3, p. 202 (1969).

13.

Chamis, C.C. and Sinclair, J.H. , "Mechanical Behavior and Fracture Characteristics of Off-Axis Fiber Composites II—Theory and Comparisons," NASA TP 1082 (January 1978 ).

14.

Nemeth, M.P. , Herakovich, C.T. and Post, D. , "On the Off-Axis Tension Test for Unidirectional Composites," Composite Technology Reviews , Vol. 5, p. 61 (1983).

15.

Hearle, J.W.S. , "Strength of Fiber Composites at an Angle to Fiber Axis," Fiber Science and Technology , Vol. 3, pp. 321-323 (1971).

16.

Tsai, S.W. , "Strength Characteristics of Composite Materials," NASA CR-224 (April 1965).

17.

Snell, M.B. , "Strength and Elastic Response of Symmetric Angle-Ply CFRP," Composites, Vol. 9, p. 167 (1978).

18.

Spencer, B. and Hull, D. , "Effect of Winding Angle on the Failure of Filament Wound Pipe," Composites , Vol. 9, p. 263 (1978).