Study on residual stress in carbon fibres by Raman spectroscopy

Based on the principle that residual stress in crystal lattice leads to change of distance among atoms, an approximate inear relationship between Raman shift and suffered strain of fibers is deduced. According to the stress-strain curve, a linear relationship between the stress and Raman shift is also deduced, and the ratio coefficient of the stress and Raman frequency shift is given. In high intensity carbon fibers, different spectra of the carbon fibers are obtained by Raman spectroscopy. The approximate linear relationship between the carbon fiber tensile strain and Raman shift is validated and the stress factor is given as well. Both the theoretic and experimental results show that the stress factor is -486.7GPa.mm. The experiment results also show that the Raman spectroscopy is a very effective method for the microstructure residual stress measurement. This method for residual stress measurement by Raman shift is able to be used in textile, biology, materials etc.