Internal strain measurement and impact response of three-dimensional angle interlock woven carbon fibre composites

Abstract

Extrinsic Fabry Perot interferometer fibre optic sensors have been utilised to measure the internal matrix strain in a three-dimensionally woven carbon fibre-reinforced polymer composite. Extrinsic Fabry Perot interferometer sensors were embedded at two levels within a four-layer three-dimensional woven composite, and comparison surface measurements were provided through resistive strain gauging and biaxial extensometry. A variation in tensile strain was found from internal measurement compared with the material surface. Through correlation with micro-graphical analysis, a link between the variations in mechanical performance and localised variations in fibre volume fraction could be established. Furthermore, the impact performance of the composite was measured and correlated with computed tomography.