Distributed strain monitoring for different composites structures with high resolution based on optical fiber sensing

Abstract Distributed strain monitoring for different composites structures has been accomplished with high resolution based on optical fiber frequency domain reflectometry (OFDR) system. The dynamic measurement range and spatial resolution of the system can be adjusted according to the objects to be monitored. In order to verify the reliability of the system, theoretical and experimental studies have been carried out. The physical model structures have been established. The sensing fiber was pasted onto the physical structure. The finite element analysis software ANSYS has been used to build 3D models of the structures in experiments, including the aluminum alloy cantilever beam model and the carbon fiber reinforced composite plate model. The simulated strain curves have been acquired based on the composite material analysis and the static analysis of module simulation according to the actual load. The experimental strain curves have been obtained by the established OFDR system. The theoretical and experimental results show that the system can achieve the spatial resolution of 1.3 mm within the measurement range of 50 m. Under certain load conditions, the maximum error between the experimental measurement results and the theoretical simulation results of the strain distribution is 2.62% for the aluminum alloy cantilever beam, and that is 2.65% for the carbon fiber reinforced composite sheet. The results verified the reliability of the OFDR system for distributed monitoring of strain.