Evaluation of interface fracture energy for single-fibre composites

Raman and luminescence spectroscopy have been used for the first time to de termine the interface fracture energy for single-fibre composites. By using the measured fibre stress distributions in single-fibre fragmentation comp osite specimens and a simple energy-balance scheme, the energy for the init iation of interfacial debonding has been estimated for carbon (T50) and alp ha-alumina (PRD-166 and Nextel 610) fibres embedded in epoxy resins. It has been found that the interface fracture energy shows good sensitivity to ch anges in the level of fibre/matrix adhesion clue to surface treatment and s izing of the fibres. It is also found that the values of interface fracture energy correlate well with measured values of interfacial shear strength d etermined for the same fibre/matrix systems. (C) 1998 Elsevier Science Ltd. All rights reserved.