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.
A carbon composite strain sensing system using an embedded array of polymide-coated fiber Bragg grating sensors, which are interrogated by a tunable laser, is described. The system is controlled from a personal computer using a customized program. The system was tested using a composite panel consisting of 28 plies of carbon fiber. Consistent strain measurements were achieved using a laser scan resolution of 0.02 nm, which corresponds to a strain resolution of approximately 15 me. Simulations of the panel were carried out using the Marc/Mentat finite element program for advanced engineering analysis. The experimental results compared well to those obtained from the simulations.