Thermal expansion of carbon–epoxy laminates measured with embedded FBGS – Comparison with other experimental techniques and numerical simulation

This paper deals with a mixed experimental–theoretical approach aiming to evaluate information given by optical fiber Bragg gratings embedded in carbon–epoxy laminates submitted to thermal expansion. FBG instrumented elementary and structural specimens are considered. The study is undertaken through a comparison of values obtained on the one hand experimentally with high temperature resisting foil gages and thermo mechanical analysis (TMA) and on the other hand numerically through a non linear FEM simulation. Discrepancies are observed when specimens are of UD type and good agreements appear when specimens are of approaching isotropic stacking sequence. To some extent, transverse effects are suspected to have a non negligible influence on the strain information delivered by the embedded FBG.