Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Strength and fracture toughness of carbon fibre polyester composites


Fracturing of carbon fibre/polyester composites has been studied by means of mechanical testing and scanning electron microscopy. Carbon fibres were surface-treated in several ways so as to vary the interlaminar shear strength of the composites, and the effect of this variation on the work of fracture was determined by means of Charpy V-notch impact tests and slow three-point bend tests on notched specimens of triangular cross-section. The effect of moisture on the fracture toughness was also studied by measuring toughness and interlaminar shear strength after exposure to steam. Improvement of the fibre/resin bond results, as expected, in an increase in the brittleness of composites and it appears that a purely mechanical bond, such as might be obtained by acid-etching the fibre surface, is less proof against deterioration in humid atmospheres than a chemical bond, such as can be obtained by the use of coupling agents. Estimates of the magnitude of various contributions to the fracture toughness show that in carbon-fibre-reinforced resins the effect of increasing the stiffness or load-bearing ability of the matrix and the work done against friction in pulling broken fibres out of the matrix contribute approximately one fifth and four fifths, respectively, of the total work of fracture.

This is a preview of subscription content, log in to check access.


  1. 1.

    R. A. Simon, S. P. Prosen, and J. Duffy, Nature 213 (1967) 1113.

  2. 2.

    B. Harris, P. W. R. Beaumont, and A. Rosen, J. Mater. Sci. 4 (1969) 432.

  3. 3.

    J. W. Herrick, P. E. Gruber, and F. T. Mansur, Avco Corporation Tech. Report AFML-TR-66-178, part 1 (1966).

  4. 4.

    J. W. Herrick and A. J. Traveis, 23rd Annual Conference of the Reinforced Plastics/Composites Division of the Society for Plastics Industry (USA), paper 16A (1968).

  5. 5.

    R. C. Novak, Philco-Ford Corporation publication U-4379 (1968).

  6. 6.

    R. A. Simon and S. P. Prosen, 23rd Annual Conference of Reinforced Plastics/Composites Division of SPI, paper 16B (1968).

  7. 7.

    W. H. Martin and J. E. Brocklehurst, Carbon 1 (1964) 133.

  8. 8.

    W. Rüland, paper presented at the Institute of Physics Conference on Fibres for Composites, Brighton (1969); also Rüland et al., Compt. Rend. Acad. Sci. (Paris) 269 (1969) 1597.

  9. 9.

    N. F. Dow, B. W. Rosen, and Z. Hashin, NASA Report CR-492 (1966).

  10. 10.

    D. M. Peters, Design Engineering (September) 29 (1968).

  11. 11.

    H. G. Tattersall and G. Tappin, J. Mater. Sci. 1 (1966) 296.

  12. 12.

    N. G. McCrum and E. L. Morris, Proc. Roy. Soc. A281 (1964) 258.

  13. 13.

    A. H. Cottrell, ibid A282 (1964) 2.

  14. 14.

    J. Mullin, J. M. Berry, and A. Gatti, J. Composite Materials 2 (1968) 82.

  15. 15.

    J. Cook and J. E. Gordon, Proc. Roy. Soc. A282 (1964) 508.

  16. 16.

    J. O. Outwater and M. C. Murphy, 24th Annual Conference of Reinforced Plastics/Composites Division of SPI, paper 11C (1969).

  17. 17.

    A. Kelly, “Strong Solids”, Oxford, Clarendon Press, 1966.

  18. 18.

    Idem, Proc. Roy. Soc. A282 (1964) 63.

  19. 19.

    G. A. Cooper and A. Kelly, in “Interfaces in Composites”, ASTM, STP 452 (1969) 90.

  20. 20.

    G. A. Cooper, J. Mater. Sci. 5 (1970) 645.

  21. 21.

    B. Harris and E. M. De Ferran, ibid 4 (1969) 1023.

  22. 22.

    E. A. Almond, J. D. Embury, and E. S. Wright, “Interfaces in Composites”, ASTM, STP 452 (1969) p. 107.

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Harris, B., Beaumont, P.W.R. & Moncunill de Ferran, E. Strength and fracture toughness of carbon fibre polyester composites. J Mater Sci 6, 238–251 (1971). https://doi.org/10.1007/BF00550019

Download citation


  • Steam
  • Fracture Toughness
  • Shear Strength
  • Carbon Fibre
  • Impact Test