X-ray diffraction studies on the stress transfer of transversely loaded carbon fibre reinforced composite

Unidirectional continuous carbon fibre reinforced epoxy composite was subjected to the stress in the direction perpendicular to the fibre direction. The applied stress was transferred to the incorporated fibre through the matrix. This stress brings the strain in the crystalline regions of carbon fibre, which was appeared as the shift of the equatorial X-ray diffraction peak position. The stress on the incorporated fibre was calculated by multiplying the crystal strain and the crystal modulus of inter-graphite networks. We here propose a novel technique "X-ray Diffraction Method" to detect the stress on the incorporated fibre in the composite under transverse load, and discussed the stress transfer in situ and non-destructively in terms of microscopic point of view. The adhesion between the matrix and the fibre was found to play an important role for the transverse reinforcement of the composite. (C) 2000 Elsevier Science Ltd. All rights reserved.