Distributed Sensor Network for Structural Health Monitoring of Ships

Our nation’s security requires that we maintain our position as the preeminent Naval force in the world. Hull fatigue is one of the key factors that reduce the lifetime of a ship. Hull inspection and maintenance increases the operation cost. Technology that reduces wear and tear on ship hulls, reduces unnecessary maintenance and avoids premature decommissioning will allow for cost reductions while using the most advanced technology. A system is needed that can measure the strain in a ship’s hull in real time and provide warnings when the hull is approaching a predetermined strain limit. Luna Innovations Incorporated proposes to develop a distributed fiber optic strain sensing network with a lifetime greater than ten years, a sensor footprint of less than 1 square cm, a measurement range of +/-5000 microstrain, and a frequency response of at least 200 Hz over a range of 400 ft. The sensor will be comprised of a single optical fiber that is less than 0.25 mm diameter. This fiber will require no electrical connections, no batteries, and no switches. Additional benefits of the system are its small size, highly rugged design and intrinsic EMI immunity.