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Effect of modulus ratio on stress near a discontinuous fiber

Matrix stress-concentration factor was shown to increase sharply with increasing modulus ratio by moiré and finite-element analyses

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Abstract

The effect of the fiber to matrix modulus of elasticity ratio varying from 1.0 to 200 was investigated for a two-dimensional plane-stress composite configuration having a simulated fiber volume fraction of 0.45 and containing a discontinuous fiber. Uniaxial loading parallel to the fibers was considered. Two independent techniques were used: moiré strain analysis and finite-element analysis. Displacements were measured from four experimental models by utilizing optical fringe-multiplication techniques. The finite-element method yielded stresses which agreed closely with those obtained from the experimental analysis. Matrix stress-concentration factor near the discontinuous fiber was found to increase rapidly with increasing modulus ratio, reaching a value of 20 for a modulus ratio of 200. The finite-element method was shown to be a valuable tool for micromechanical stress analysis of composite materials, and the accuracy of strain analysis by moiré-fringemultiplication techniques was demonstrated for problems containing sever strain gradients.

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Abbreviations

A :

cross-sectional area

E :

modulus of elasticity

P :

force

V f :

fiber-volume fraction

ε:

strain

ν:

Poisson's ratio

σ:

maximum principal stress

τ:

maximum shear stress

c :

composite

f :

fiber

m :

matrix

References

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Authors and Affiliations

  1. Department of Transportation, National Highway Traffic Safety, Adiministration, 20590, Washington, D.C.

    T. F. MacLaughlin (Safety Standards Engineer)

  2. Mechanical Engineer, Watervliet Arsenal, 12189, Watervliet, N.Y.

    T. F. MacLaughlin (Safety Standards Engineer)

  3. Department of Civil Engineering, College of Engineering, Virginia Polytechnic Institute and State University, 24061, Blacksburg, Va.

    R. M. Barker (Associate Professor)

Authors
  1. T. F. MacLaughlin
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  2. R. M. Barker
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MacLaughlin, T.F., Barker, R.M. Effect of modulus ratio on stress near a discontinuous fiber. Experimental Mechanics 12, 178–183 (1972). https://doi.org/10.1007/BF02330270

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  • DOI: https://doi.org/10.1007/BF02330270

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