Inelastic Analysis of a Unidirectional Composite Subjected to Transverse Normal Loading

Abstract

Composite material behavior is divisible into three distinct re gimes, linear elastic response up to the elastic limit, inelastic be havior beyond the elastic limit and up to that point at which first failure occurs locally, and subsequent crack propagation and total composite failure. The first regime has been thoroughly explored in previous investigations, while the second is the main topic of the present paper. The third is briefly discussed and is a subject under investigation.

Utilizing a finite element analysis, numerical results are obtained for composite behavior beyond the elastic limit and up to first failure. Examples representative of several actual material systems are presented and discussed in detail.

Results indicate that extensive local yielding and redistribution of stresses can occur in a composite with very little indication of such behavior being apparent by observation of the total stress- strain response of the composite alone. Thus, the establishment and interpretation of design criteria and theories of failure should be evaluated in light of these results and their implications with re spect to such phenomena as fatigue life and fracture behavior, among others.

Get full access to this article

View all access options for this article.

References

C.C. Chamis and G.P. Sendeckyj , "Critique on Theories Predicting Thermoelastic Properties of Fibrous Composites," J. Composite Materials , Vol. 2 (1968), p. 332.

D.F. Adams and S.W. Tsai , "The Influence of Random Filament Packing on the Transverse Stiffness of Unidirectional Composites," J. Composite Materials, Vol. 3 (1969) , p. 368.

B.W. Shaffer , "Elastic-Plastic Stress Distribution Within Reinforced Plastics Loaded Normal to Its Internal Filaments," AIAA Journal, Vol. 6 (1968), p. 2316.

R.L. Foye , "An Evaluation of Various Engineering Estimates of the Transverse Properties of Unidirectional Composites," Proceedings of the Tenth National SAMPE Symposium-Advanced Fibrous Reinforced Composites, November 1966.

D.R.J. Owen , J. Holbeche , and O.C. Zienkiewicz , "Elastic-Plastic Analysis of Fibre-Reinforced Materials," Fibre Science and Technology, Vol. 1 ( 1969 ), p. 185.

O.C. Zienkiewicz , The Finite Element Method in Structural and Continuum Mechanics, McGraw-Hill (1967) .

P.V. Marcal , Finite Element Analysis with Material Nonlinearities-Theory and Practice , Office of Naval Research Contractor Report N00014-0007/3 ( August 1969) .

P.V. Marcal , "A Comparative Study of Numerical Methods of Elastic-Plastic Analysis," AIAA Journal, Vol. 6 (1968), p. 157.

D.F. Adams and D.R. Doner , "Longitudinal Shear Loading of a Unidirectional Composite," J. Composite Materials, Vol. 1 ( 1967), p. 4.

10.

D.F. Adams and D.R. Doner , "Transverse Normal Loading of a Unidirectional Composite," J. Composite Materials , Vol. 1 (1967), p. 152.

11.

J.L. Swedlow and W.H. Yang , Stiffness Analysis of Elasto-Plastic Plates, Air Force Rocket Propulsion Laboratory Contractor Report AFRPL-TR-66-5 (January 1966).