Paper number 546

LONGITUDINAL COMPRESSIVE BEHAVIOUR OF CARBON FIBRES

N. Oya¹, D. J. Johnson¹, and H. Hamada²

1School of Textile Industries, University of Leeds
Leeds, West Yorkshire, LS2 9JT, UK
2Advanced Fibro-Science, Kyoto Institute of Technology
Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan

Summary

Longitudinal compressive strengths of PAN-based carbon fibres were measured by a new direct measurement method; the results were correlated with microstructural parameters obtained from wide-angle X-ray scattering. Compressive strengths were found to be much lower than tensile strengths; they were independent of crystallite disorder and crystallite size for HS (high strength) fibres, but were dependent on porosity. However, compressive strengths changed in respect of crystallite disorder, size and porosity for HM (high modulus) fibres. From these compressive strength-structure relations, it was concluded that the high strengths of HS fibres have been achieved by low porosity, and that the high moduli of HM fibres have been obtained by reduced disorder and larger crystallites, which have also led to a few large pores. The compressive strengths of HM fibres are lower than those of HS fibres.

Keywords

carbon fibre, compression, stress, modulus, scanning electron microscope (SEM), X-ray diffraction, microstructure, CFRP.