Residual strain measurement and impact response of optical fibre Bragg grating sensors in fibre metal laminates

Recently, optical fibre Bragg gratings have attracted a significant amount of attention as optical fibre sensors for measuring strain in composite structures. Indeed, the growth of optical fibre technology has spurred the development of smart composites capable of measuring real-time internal strain within structures and an assortment of measurands such as temperature, pressure and chemical. In this paper, optical fibre Bragg grating sensors are embedded in a novel fibre-metal laminate composite, to demonstrate the potential of fibre Bragg grating sensors in measuring post-processing residual strain within a multimaterial structure. Repeated impact tests in the region of the grating have been performed to investigate the survivability of the sensor. In addition, post-impact sensor linearity tests have then been carried out to evaluate the sensor response to load.