FIBER BRAGG GRATING SENSOR SYSTEM FOR MONITORING COMPOSITE AEROSPACE STRUCTURES

Abstract

To investigate strain-sensitive characteristics of fiber Bragg grating (FBG) sensors, a minimal sensing system consisting of multiplex FBG sensors and signal demodulating and processing instruments was constructed. FBG sensors were designed with different package structures for respectively sensing strain or temperature parameters, and they returned measurand-dependent wavelengths back to the interrogation system for measurement with high resolution. In this paper, tests were performed on structure samples with step-wise increase of deformations. Both FBG sensing system and strain gages were tested and compared. Experimental work proved that the FBG sensing system had a good level of accuracy in measuring the static response of the tested composite structure. Moreover the additional advantages such as damp proofing, high sampling rates and real-time inspection make the novel system especially appropriate for load monitoring and damage detection of aerospace structures.