Advertisement

Journal of Materials Science

, Volume 8, Issue 12, pp 1765–1787 | Cite as

The impact strength of fibre composites

  • T. Williams
  • G. Allen
  • M. S. Kaufman
Papers

Abstract

Two models have been developed which predict the crack initiation energy, notched impact strength and unnotched impact strength of fibre composites. One is applicable to composites containing short fibres and the other to composites containing long fibres. Data obtained with randomly oriented short fibre composites were consistent with the one model. The other model has been verified using composites containing uniaxially oriented long fibres and long fibres oriented randomly in a plane. The success of the model demonstrates that the high notched impact strength with long fibres is due to the redistribution of stress away from the stress concentrating notch, the extra stress that can be held by the fibre relative to the matrix and the work required to pull fibres out of the matrix during crack propagation. The parameters which have been shown to control the fracture energy are composite modulus, fibre length, fibre volume fraction, effective fibre diameter, fibre tensile strength and the coefficient of friction during fibre pull-out from the matrix. The matrix toughness on the other hand usually has no effect at all for composites containing fibres randomly oriented in two dimensions and only a minor effect in exceptional cases. The shear strength of the fibre-matrix bond has only an indirect effect in that it controls the number of fibres which pull out rather than fracture.

Keywords

Shear Strength Crack Initiation Impact Strength Fibre Composite Fibre Volume Fraction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    P. I. Vincent, “Impact tests and service performance of thermoplastics” (The Plastics Institute London, 1971).Google Scholar
  2. 2.
    J. O. Outwater andM. C. Murphy, 24th Annual Conference of Reinforced Plastics/Composites Division of SPI, paper 11C (1969).Google Scholar
  3. 3.
    J. H. Davies,Plastics and Polymers 39 (1971) 137.Google Scholar
  4. 4.
    H. Brody andI. M. Ward,Polymer Eng. Sci. 11 (1971) 139.CrossRefGoogle Scholar
  5. 5.
    J. K. Lees,ibid 8 (1968) 195.CrossRefGoogle Scholar
  6. 6.
    A. Kelly,Proc. Roy. Soc. A319 (1970) 95.Google Scholar
  7. 7.
    A. H. Cottrell,ibid A282 (1964) 2.Google Scholar
  8. 8.
    N. L. Hancox,Composites,3 (1971) 41.CrossRefGoogle Scholar
  9. 9.
    M. R. Piggott,J. Mater. Sci. 5 (1970) 669.CrossRefGoogle Scholar
  10. 10.
    P. Hing andG. W. Groves,ibid 7 (1972) 427.Google Scholar
  11. 11.
    G. Allen, M. J. Bowden, D. J. Blundell, F. G. Hutchinson, G. M. Jeffs andJ. Vyvoda, ICI/Manchester University Joint Laboratory report (1971), to be published.Google Scholar
  12. 12.
    G. Allen, M. J. Bowden, D. J. Blundell, G. M. Jeffs, J. Vyvoda andT. White, ICI/Manchester University Joint Laboratory report (1971), to be published.Google Scholar
  13. 13.
    J. D. Emmerson, to be published.Google Scholar
  14. 14.
    G. V. Shiriajeva andG. D. Andrevskaya,Sov. Plastics 4 (1962) 40.Google Scholar
  15. 15.
    D. C. West, “Experimental Mechanics” (Instron Application Series PC-18, 1964).Google Scholar
  16. 16.
    J. H. Westbrook,Physics Chemistry Glasses 1 (1960) 32.Google Scholar

Copyright information

© Chapman and Hall Ltd 1973

Authors and Affiliations

  • T. Williams
    • 1
  • G. Allen
    • 2
  • M. S. Kaufman
    • 2
  1. 1.ICI Corporate LaboratoryRuncorn
  2. 2.Chemistry DepartmentThe University of ManchesterManchester

Personalised recommendations