Various static loading condition monitoring of carbon fiber composite cylinder with integrated optical fiber sensors

Composite cylinder structures are widely used in various engineering fields. Monitoring the health state is an essential method for ensuring the safe operation of the structures. Embedded distributed fiber optic sensors have gained significant interest as they effectively address issues related to aesthetics and protection. This paper presents a strain monitoring method that involves embedding optical fibers along a spiral path within composite cylindrical structures. Additionally, a monitoring method is proposed to evaluate the structure's health state using the strain data collected in this manner. To validate the measurement accuracy of the fiber optic sensors, a comparison is made between the measurements obtained from the embedded fiber optic sensors and surface-bonded strain gauges under different working conditions. The results demonstrate excellent consistency, establishing the reliability of the fiber optic sensors. In this study, a distributed fiber optic sensor network and embedding scheme are designed for large composite cylinder structures, and strain monitoring experiments at various conditions, including pressure, bending, and hoisting loads, are conducted. Finite element simulations are also performed at corresponding working conditions, and the effectiveness of fiber optic sensor measurement is confirmed by comparing normalized simulation results with measured results. The embedded distributed fiber optic sensors effectively capture the strain changes at the reinforcement frame located in the middle of the cylinder structure, which aligns with the theoretical analysis of the cylinder structure under varying loads. This study on the embedding of fiber optics in large composite cylinder structures provides valuable insights for structural health monitoring purposes.