Strain sensing in carbon composite material using embedded Fibre Bragg Grating sensors

This paper reports on a Fibre Bragg Grating based sensor system, using a LabVIEW interface, for the measurement of strain, primarily in carbon composite materials. The process of embedding the sensors is outlined, system operation is explained and some sensitivity considerations are addressed. The system was firstly used to interrogate a single fibre Bragg grating that was embedded in a cantilever-type sample of a carbon/epoxy laminate. The accuracy of the system was examined by comparing results with those from a conventional resistive foil strain gauge. A composite "smart" panel was then constructed incorporating an array of four FBG sensors. The panel was subjected to various strain conditions, and sensor readings were used to obtain the resultant distribution of strain within the panel. Results were verified using special modelling software.