OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Sustainment; Trusted AI and Autonomy OBJECTIVE: Develop an imaging system suitable for in-situ detection of hidden corrosions/defects in naval air vehicles. DESCRIPTION: The deleterious consequences of fatigue and fracture in metallic structures arising from local microstructure, mechanical loading, thermal effects, and the corrosiveness of the maritime environment, usually lead to corrosions/defects of aircraft landing gears or other naval aerial platform surfaces. At the burgeoning of the corrosion/crack/fracture/damage, the damage areas are underneath some kind of protective coating or paints and therefore render conventional visible early inspection and evaluation ineffective. Early detection of the corrosion and related defects is critical, as it would reduce the remediation cost, improve the operational safety, and minimize mission downtime of fielded assets. Traditional methods for detecting corrosion defects are inefficient, and involve costly removal and replacement of the coatings and paints for visual inspection of the underlying surface. Removal and replacement of these polymer or painted sections involve costly operations in terms of labor and materials costs. This SBIR topic seeks a solution of non-destructive evaluation (NDE) of hidden corrosion underneath paints or polymers. Corrosion of aluminum alloys generally develops as pitting or thinning, and in general changes a nominally smooth surface to an uneven and irregular surface, which can then result in cracking. The detection of this type of corrosion is not within line of sight. The detection of corrosion on aluminum formers that are under composite skins without disassembly would be very beneficial. Inspection through top coats would be ideal. The proposed solution should be able to detect defects with sizes greater than 0.005 in. (0.0127 cm) on a curved surface with a radius of curvature 2 in. (5.08 cm) radius or less. The proposed solution should be able to detect fastener corrosion. The proposed method should also detect corrosion on fastener threads without the need for disassembly. This SBIR topic focuses on development of technologies that will image corrosion and defects through coatings and paints rapidly enough to support a sampled or completed NDE of an aircraft. The system should be portable that weighs no more than 12 lbs. (5.44 kg), be capable of expected constant system mobility without need for recalibration more than once annually, and sufficiently robust for operations under harsh maritime environmental conditions. The system needs to be in compliance with all FCC regulations. The preferred system prototype solution should yield detection results as close to real time as possible, and be equipped with a graphical user interface that is easy to use and understood by an operator with relevant training. It is also expected that any proposed system should have built-in wireless capability that can send imaging data to a remote user system for further detection analysis and evaluation. PHASE I: Develop an imaging system with the capability to meet the operational, frequency, SNR, minimum corrosion/defect size, minimum paints/coatings thickness, and graphical user interface and wireless transceiver as stated in the Description. Detection of a defect is defined as the ability to accurately distinguish the defect from surrounding regions that do not contain the defect, and display the location and size of the defect in a graphic user interface. Demonstrate the feasibility of the concept to detect the aforementioned hidden defects via modeling and simulation. Concept feasibility will be supported by appropriate analyses and laboratory experiments. Provide a Phase II development plan that includes performance goals and key technical milestones. The Phase I effort will include prototype plans to be developed under Phase II. PHASE II: Develop a prototype suitable for evaluation. Evaluate the performance of the prototype with regard to the goals defined in Phase I on a Navy provided test panel that is equivalent to testing on an in-service Navy asset under similar field conditions. Based on the initial results of the evaluation, refine the prototype and demonstrate that the final prototype meets the performance specifications stated in the Description. Deliver the final prototype at the end of the Phase II that is ready for field testing by the Navy. PHASE III DUAL USE APPLICATIONS: Transition the technology into a system that can be acquired by the Navy. The Phase III plan should include testing, validation, certification, and qualification for Navy use. With the ability to inspect aluminum material/structure under polymer and paint, this will provide the private sector with new instrumentation for detecting degradation of aluminum material. This instrumentation will certainly improve the maintenance of commercial aviation assets. REFERENCES: Anastasi, R. F., Madaras, E. I., Seebo, J. P., Smith, S. W., Lomness, J. K., Hintze, P. E., Kammerer, C. C., Winfree, W. P., & Russell, R. W. (2007, April). Terahertz NDE application for corrosion detection and evaluation under shuttle tiles. In Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2007 (Vol. 6531, pp. 261-266). SPIE. https://doi.org/10.1117/12.715128 Wilson, A., Vincent, P., McMahon, P., Muscat, R., Hayes, J., Solomon, M., Barber, R., & McConnell, A. (2008, December). A small, low-power, networked corrosion sensor suite. In Proceedings of the 2nd Asia-Pacific Workshop on Structural Health Monitoring, Corrosion, Melbourne, Australia (pp. 2-4). https://www.researchgate.net/profile/Peter-Vincent-4/publication/27257497_A_small_low-power_networked_corrosion_sensor_suite/links/5990efc3aca2721d9b72e1db/A-small_low-power_networked_corrosion_sensor_suite.pdf Hoen-Velterop, L. (2017, August 7 10). Assessing the corrosion environment severity helicopters encounterusing environmental sensors [Paper No. 2017-400177]. 2017 Department of Defense Allied Nations Technical Corrosion Conference, Birmingham, AL, United States. https://www.dau.edu/cop/cpc/_layouts/15/WopiFrame.aspx?sourcedoc=/cop/cpc/DAU%20Sponsored%20Documents/Assessing%20the%20Corrosion%20Environment%20Severity%20Helicopters%20Encournter%20Using%20Environmental%20Sensors.pdf&action=default KEYWORDS: Nondestructive Inspection; NDI; Corrosion detection; aluminum formers; fastener corrosion; imaging corrosion; Al corrosion
