Fiber stress analysis in short fiber reinforced composites by means of laser Raman spectroscopy

The Raman spectrum of a carbon fiber shifts with the applied stress on the fiber. In this paper, stresses of carbon fibers in short fiber reinforced c omposites were evaluated according to the shifts in Raman spectra. The stre ss levels of individual fibers in the composites could be evaluated by this spectroscopy. The change of stress distribution along the fibers by deform ation could also be measured, connected with the microscopic failure in the composites. It has become clear that the shifts in Raman spectra are direc tly related to the deformation and fracture of the short fiber reinforced c omposites.