Novel development of fiber Bragg grating in monitoring composite laminates

Signal of the fiber Bragg grating (FBG) sensors posses light source fluctuation immunity and multiplexing ability, which is suitable for sensing network system and thus is a hot research topic in the sensor field. Several types of defects like warping, crack, and delamination are generated on composite laminates in use. FBG can response to these different types of defects. Recent research and novel development of using FBG sensors in composite laminates to monitor thermal residual stress, multi-axis strain fields, delamination, impact position, and crack propagation, were critically reviewed. The existing problems were analyzed. The studies show that the materials and technology of FBG packaging can directly affect the relation between wavelength shift and measuring parameters. A thin adhesive layer, high modulus coating material and enough embedded length of FBG sensor are good for monitoring real strain of composite laminates.