Integrated system health management for platforms systems and subcomponents is now an integral part of planning the design and construction of future assets (e.g., ships, aircraft, vehicles, buildings). Health management of critical assets depends on two equally important processes. The first is health diagnostics; the second is health and lifetime prediction, or prognostics. The diagnostic step certainly feeds vital information to the prognostic arm. A variety of sensors have been developed, and continue to be developed or enhanced, to detect and analyze strains and vibrations, as well as to "see" and identify defects such as cracks and corrosion pits.
Research Concentration Areas
Currently, the program is investigating:
- New fiber optic sensor concepts for metallic and polymer matrix composite structures that can monitor temperature, strain, vibration and acoustic emission monitoring
- Fiber optic approaches to ultrasound generation for active interrogation of structures
- Distributed sensor architectures for effective system usage and damage evolution tracking
- Ultrasonic wave propagation and scattering models
- Acoustic emission modeling, source identification and severity characterization
- Addressable fiber optic energy distribution and communication nodes
- Addressable wireless nodes with energy harvesting, storage, sensing and communication capabilities
- Interrogation electronics and data acquisition software
Because of the deleterious consequences of fatigue and fracture in metallic structures, the program is particularly interested in monitoring and modeling the evolution of this degradation and failure modes. Since damage frequently arises from a combination of the local microstructure, mechanical loading, thermal effects and the corrosiveness of the environment, monitoring these parameters and the integrity of the protective coating systems and understanding how these contribute to acceleration of damage accumulation in metallic structures is also a program goal.
Additive Manufacturing (AM) offers opportunities in terms of new and improved component and structural designs, and the possibility to reduce procurement lead times for out-of-production, structural components and affordable, low-volume production runs. This program also invests in metal AM process monitoring sensors and controls to ensure the quality of the final products. The program is also investing in NDE technologies and in-place sensors to ensure safe operation of these components throughout the entire operational life of the platform.
Research Challenges and Opportunities
Although significant progress has been achieved in recent years in the research concentration areas mentioned above, there still remain significant barriers to the use of these fiber optic sensors including the below basic and applied research areas of interest.
- Increasing the fiber optic sensor density over all spectral ranges
- Understanding and improving the coupling of ultrasonic energy into the fiber sensors
- Developing reliable models capable of correlating the sensor’s signal with the defect size and many other challenges and opportunities
- Researching new fiber optic sensor modalities of all types such as for monitoring the outside environmental parameters, magnetic signatures or bond strength, and others
- Generating frequency-controlled, ultrasonic energy at multiple points along the fiber
- Developing addressable fiber optic switching nodes as a means of expanding the network with new branches and to control the distribution of energy and information along the network
- Reducing the size and weight of the main control unit without eliminating overall capability
- Developing intelligent sensor interrogation architectures that are capable of extracting the maximum amount of information from the structure with the minimum requirements for hardware
How to Submit
For detailed application and submission information for this research topic, please refer to our broad agency announcement (BAA) No. N00014-22-S-B001.
Contracts: All white papers and full proposals for contracts must be submitted through FedConnect; instructions are included in the BAA.