Journal of Materials Science

, Volume 7, Issue 11, pp 1315–1321

On the re-inforcement of thermoplastics by imperfectly aligned discontinuous fibres

  • W. H. Bowyer
  • M. G. Bader
Papers

DOI: 10.1007/BF00550698

Cite this article as:
Bowyer, W.H. & Bader, M.G. J Mater Sci (1972) 7: 1315. doi:10.1007/BF00550698

Abstract

Studies of deformation behaviour of short fibre reinforced thermoplastics are complicated by the facts that usually a wide range of fibre lengths are present in moulded test pieces and that the fibres are not systematically oriented with respect to any test direction. An equation has been derived for the stress/strain curve of such a material. This has been used to determine fibre/matrix bond strengths in two glass/nylon 6.6 and two glass/polypropylene composites from measured stress/strain curves and fibre length distributions.

It is concluded that major improvements in the properties of these materials will only be achieved by modifying processing to retain longer fibres.

List of symbols

Ec

Modulus of composite

Ef

Modulus of fibre

Em

Modulus of matrix

Vf

Volume fraction of fibre

σc

Stress in the composite

σf

Peak stress in a fibre

\(\bar \sigma _f\)

Average stress in a fibre

σuf

Ultimate strength of fibres

σm

Stress in matrix at fibre failure strain

σuc

Ultimate strength of the composite

c

Strain in composite

uc

Ultimate strain of the composite

τ

Shear strength of the fibre matrix bond

L

Fibre length

Lɛ

Critical fibre length at a composite strain e

Lc

Critical fibre length for fibre failure

r

Fibre radius

Copyright information

© Chapman and Hall Ltd. 1972

Authors and Affiliations

  • W. H. Bowyer
    • 1
  • M. G. Bader
    • 1
  1. 1.Department of Metallurgy and Materials TechnologyUniversity of SurreyGuildfordUK

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