Strain Measurement of Composite Laminates Using Fiber Bragg Grating Sensors

Fiber Bragg grating(FBG) sensors, one of the fiber optic sensors(FOS), based on the wavelength division multiplexing(WDM) technology are ideally suitable for structural health monitoring of composite materials and structures. Proper monitoring of measurands in FBG sensor systems requires accurate measurement of the Bragg center wavelength, and the ability to track rapid shifts of the wavelength. Thus we constructed a FBG sensor system by use of a wavelength-swept fiber laser(WSFL) in the present study. The quasi-static and dynamic strains were measured by the constructed FBG sensor system for investigation of the system performance. In addition a real-time signal processing program was made to measure strains. Three FBG sensors in an optical fiber were used to measure strains of the laminated composite panel under compressive axial loading. Experiments showed that the constructed FBG sensor system and the real-time signal processing program could successfully measure the strain of composite laminates.