Distributed Optical Fibre Smart Sensors for Structural Health Monitoring
Faculty of Computing, Health and Science
School of Engineering (SOE) / Centre for Communications Engineering Research
In general, Structural Health Monitoring (SHM) can utilize either distributed smart sensors, or multiplexed optical fiber sensors. We demonstrate the implementation of Distributed Optical Fiber Smart Sensors (DOFSS) for SHM. That is, the distribution of both intelligence and sensors in an optical fiber based sensor network. Optical fibers offer advantages that make them highly desirable as sensors, the most important for SHM being versatility. For example, Fiber Bragg Gratings (FBGs) can be used to detect acoustic emissions, actively generated acoustoultrasonic signals, dynamic strain (e.g. vibration), static strain (e.g. load monitoring), etc. multiplexing is seen as the primary advantage of FBGs, enabling large numbers of sensors (1000), to be connected together. However, multiplexing of FBG sensors uses a single transmitter, receiver, processor, and fiber length. To ensure that a SHM system is robust, these components along with the sensors need to be distributed. This goes towards achieving NASA’s goal of robust or ageless aerospace vehicles. To achieve this, we have developed a Smart Transducer Interface Module (STIM) which can be linked together giving a DOFSS network. The distribution of intelligence around the structure means that communications and power for the network are a significant consideration. Since optical fiber will be utilized for the sensing, then these “wired” links, can be utilized for the distribution of communications and power, using WDM to combine the signals together.