In service monitoring of fibre reinforced composites with Bragg sensors

In this paper, results are shown from research carried out on the application of optical fibre sensors for remote monitoring of composite materials. Tests carried out on bare optical fibres with Bragg sensor show the applicability of these sensors for strain sensing. In a next stage, these optical fibres have been embedded into test specimens made of carbon fibre reinforced epoxy and have been subjected to static loading in bending tests. The measured signal from the Bragg sensor is linear with the applied strain. Optical fibres with Bragg sensor have also been embedded into filament wound pressure vessels, made of glass fibre reinforced epoxy. Tests carried out on such a pressure vessel include static loading and slowly varying load schemes. The Bragg signal is nearly perfectly linear with the applied pressure. The results support the applicability of Bragg sensors for continuous monitoring of composite materials.