EXPERIMENTAL RESULTS AND FINITE-ELEMENT MODELING OF AN EMBEDDED POLARIMETRIC SENSOR

'Smart structures' or 'smart skins' will require structurally integrated sensing systems that can operate in practical situations. Optical sensing techniques are receiving considerable attention for the monitoring of such systems. In this work an optical-fibre sensor has been embedded, without removing its acrylate protective coating, in a glass fibre-reinforced polymer. A single-ended polarimetric sensor was utilized with a large dynamic range for strain measurements up to 2000 mu epsilon, at which value the sensor failed. The optical measurements show good agreement with conventional electrical resistance strain gauge measurements. Finite element modelling was used to investigate the stress/strain distributions within the composite material and the embedded optical fibre. The modelling results show excellent agreement with the experimental results and suggest that the soft acrylate coating is debonding, thus reducing the sensor's dynamic range.