Quantitative measurement of interlaminar stress in CFRP laminates using fiber Bragg Gratings

CFRP materials are widely used in aircraft manufacturing, and ensuring the safety and reliability of these materials is crucial for flight safety. The acquisition of interlaminar stress can effectively evaluate material performance. This article introduces a CFRP interlaminar stress quantitative measurement method based on the stress birefringence effect of Fiber Bragg Gratings. This sensor converts the refractive index change of fiber stress birefringence into the bandwidth and peak splitting changes of the grating spectrum, simplifying the experimental setup and achieving real-time monitoring of CFRP interlaminar stress. The interlaminar stress of the CFRP laminate in this article significantly increases during the cooling stage of thermal curing and ultimately remains at a stable level of 17.6 N/cm. Sensitivity of the interlaminar stress sensor is 9.61 pm/(N/cm). This article provides an effective method for real-time monitoring of CFRP interlaminar stress throughout the entire curing cycle. It also demonstrates the feasibility of providing data support for CFRP manufacturing process improvement through experimental verification.