TECHNOLOGY AREAS: Materials/Processes, Sensors

ACQUISITION PROGRAM: 73R Adv Sub Sys Dev Prog (PE603561, Proj 2033) and ONR AMP FNC

OBJECTIVE: Develop an innovative structural health monitoring (SHM) system capable of detecting and characterizing early signs of damage to composite propellers through an in-situ network of sensors/actuators and diagnostics algorithms.

DESCRIPTION: Composite propellers are being developed by the Navy for a number of potential benefits, including reducing weight and maintenance requirements, while increasing design flexibility and performance. The lack of Navy knowledgebase on composite propellers would result in excessive design margins and extensive structural testing to mitigate the risk of failure during operation. An intelligent structural health monitoring system capable of detecting and characterizing (size, location, and nature of) damage to composite propellers will reduce design margins and the need for extensive physical testing. While in service, an SHM system applied to composite propellers would decrease operational costs by reducing the amount of scheduled inspection and maintenance.

This SBIR seeks to develop innovative approaches to sensing mechanisms, communication types (wired or wireless), and damage detection methodologies. Damage mechanisms could range from matrix cracking, delamination, and erosion, to more severe damage such as impact and shock. Sensors must withstand an extreme seawater environment including shock, repeated cyclic motion, and high pressure that are unique challenges to Naval composite propellers. Necessary sensors and actuators may be either embedded in or surface mounted on the structure, without degrading structural and hydrodynamic performance of the composite propeller. Sensors and electronics must be integrated into the overall structural design. The data acquisition and analysis system shall be serviceable from inside the vessel or located adjacent to the propeller.

PHASE I: Evaluate various approaches to sensing and analyzing structural health. Develop an SHM system concept capable of detecting damage on a notional submerged composite beam in water. Fabricate a benchtop prototype system consisting of composite beam(s), sensors, data acquisition, and processing system. Demonstrate early stage damage detection and characterization capability in water.

PHASE II: Based on the Phase I development, validate the SHM system through prototype demonstration in two stages: (1) laboratory testing of a scaled model propeller blade, and (2) in-water testing of a large-scale propeller on a Navy demonstration platform, LSV-2. If a propeller of a classified design is used for the large-scale testing on LSV-2, and the contractor does not have the appropriate clearance, the Navy program office will facilitate obtaining personnel and facility clearance for the contractor.

PHASE III: A damage prognosis capability will be developed based on the damage detection capability using the SHM system. Transition the SHM technology to NAVSEA 73R Advanced Submarine Systems Development Program for future full-scale demonstration.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The SHM technology could be integrated into any composite structures that present a significant risk of failure. Commercial shipping and tourism industries could also benefit from the SHM system.

REFERENCES:
1. Bonanni, Caiazzo, Gregory, Stager, Telegadas, "Best Practices for Composite Non-Pressure Hull Submarine Structure Based on Findings and Lessons Learned from the Composite Advanced Sail Program for the USS Virginia (SSN 774) Class", NSWCCD-65-TR-2008/28, February 2010

2. Adams, D.E., 2007, Health Monitoring of Structural Materials and Components, John Wiley & Sons, West Sussex.

3. Farrar, C. R. and Worden, K., 2007, "An Introduction to Structural Health Monitoring," Phil. Trans. R. Soc. A, 365, 2007, pp. 303-315.

4. Farrar, C. R. and Lieven, N. A. J., 2007, "Damage Prognosis: the Future of Structural Health Monitoring," Phil. Trans. R. Soc. A, 365, pp. 623�632.

5. Sohn, H., 2007, "Effects of Environmental and Operational Variability on Structural Health Monitoring," Phil. Trans. R. Soc. A, 365, 539�560.

6. Sohn, H., Farrar, C. R., Hemez, F. M., Czarnecki, J. J., Shunk, D. D., Stinemates, D. W. & Nadler, B. R., 2003, "A Review of Structural Health Monitoring Literature: 1996�2001," Los Alamos National Laboratory Report, LA-13976-MS.

7. Marsh, G., 2004, "A new start for marine propellers?" Reinforced Plastics, Volume 48, Issue 11, pp. 34-38.

8. Seaver, M., Trickey, S. T., and Nichols, J. M., 2006, "Strain Measurements from FBGs Embedded in Rotating Composite Propeller Blades," in Optical Fiber Sensors, OSA Technical Digest

9. Mouritz, A. P., Gellert, E., Burchill, P., and Challis, K., 2001, "Review of Advanced Composite Structures for Naval Ships and Submarines," Composite Structures, Vol. 53, No. 1, pp 21-42.

KEYWORDS: Structural Health Monitoring; SHM; Composite Propeller; Composites; Sensors; Damage Detection

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between November 10 and December 12, 2010, you may talk directly with the Topic Authors to ask technical questions about the topics. Their contact information is listed above. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting December 13, 2011, when DoD begins accepting proposals for this solicitation.

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