Internal strain measurement and cure monitoring of 3D angle interlock woven carbon fibre composites

This study presents a methodology to accurately embed EFPI (Extrinsic Fabry Perot Interferometer) fibre optic sensors within the resin channels of 3D woven composite for the purpose of monitoring strain during tensile tests on a 3D woven composite. Using the same sensors the cure induced strain measurement was developed into a valid in situ cure monitoring technique for an epoxy matrix composite through correlation with rheological based cure strain data. Specific strain events were attributed to the gelation and vitrification phases of the epoxy cure cycle.