| Popis: |
Fiber-optic based sensors and sensor networks are being increasingly used for a variety of sensing applications in composite structures. In this paper, we propose a multifunctional fiber optic network configuration where the fiber-optic network can serve a dual role -- as a communications network and as a health monitoring system. This can be made possible through wavelength division multiplexing, which allows multiplexing of multiple wavelengths into a single fiber. For example, multi-axis fiber Bragg gratings operating at 1550 nm can be used to sense strain, temperature, humidity etc, while allowing use of 1310 nm wavelength for communications. The goal is to develop a smart network that can interrogate the state of the structure on demand using fiber-optic gratings and also use the same fiber-optic network for communication as a data bus integrated in the structure. Such architectures are desirable for applications such as next generation lightweight systems for military as well as commercial composites industry, where real-time monitoring and cross functionality are required of structural materials. A composite laminate was fabricated with an embedded fiber Bragg grating and subjected to a 3-point bending test, while being connected to a computer network. Network traffic in the composite and strain under 3-point bending were monitored simultaneously. Results show no network performance deterioration up to composite failure, thus allowing the same fiber to serve both as a data bus and a sensor system. |
