Application of fiber Bragg grating to continuous monitoring health state of three-dimensional braided composites

In order to achieve continuous monitoring the health state of three-dimensional braided composite materials,the fiber Bragg grating(FBG) sensor has been embedded in composite material specimens based on braiding process.The paper analyzes relations between internal strain of the composite material and FBG signal under tension load.The results show that there is a good linear relationship between FBG strain sensor signal and specimen strain.The surface braiding angle of three-dimensional braided composite has a certain influence on the FBG signal.The embedding of the FBG sensor has little impact on the mechanical properties of the composite materials.These findings provide a theoretical basis for the study of health state assessment algorithms of materials during operation under the space environment and for continuous monitoring the health state of three-dimensional braided composite materials for aerospace.