Development of Flaws in Complex Geometry Coated Turbine Engine Components for Vibrothermography NDE

ABSTRACT: There is a need for a low cost reliable method to detect cracks in turbine engine components that utilize surface coatings for durability. Currently, many parts are scrapped due the cost of coating removal required to perform conventional inspection. Vibrothermography, or SIR, has shown to be a potential NDE process that may not require coating removal. Actual engine parts with representative fatigue cracks are needed to establish feasibility of this new NDE/NDI method to reveal defects in parts during overhaul activities. This is a proposal to demonstrate the ability of SIR to produce representative fatigue cracks, and to detect cracks present in coated parts. BENEFIT: The effort proposed in this SBIR is a key step towards FTTs goal of becoming the provider of state-of-the-art NDE equipment based on vibrothermography technology. Completion of the Phase II goal to deliver statistical quantities of cracked parts, followed by positive POD demonstration results (proposed by FTT as part of Airfoil Sustainment through Automated Inspection and Repair, AF151-054), will further validate one of the most compelling uses of vibrothermography Inspection. That application is to detect cracks lying beneath overlay coatings in critical components and thus eliminate the need to strip and recoat serviceable parts, resulting in significant cost avoidance. In order to implement a new inspection technology, a statistically-based inspection reliability demonstration is required by Air Force structural integrity programs. With few exceptions, a clear path to a valid POD demonstration in accordance with MIL-HBK-1823, Rev. A must be shown, or the new technology will be stalled. It isn't likely that the challenge of designing suitable coated, cracked engine parts will be met without successful completion of this series of SBIR programs. Widespread implementation of vibrothermography for Air Force engine programs would be stalled. Assuming that the series of SBIR programs is successful, the population of coated cracked parts that is produced may be used for years through many demonstrations if they are properly maintained. Possible uses extend beyond Air Force engines to other military services, and ultimately to commercial depot applications. In addition to supporting the Air Force and other US military services and agencies with Enhanced AIIS systems, FTTs commercialization strategy includes making the same equipment available to jet engine original equipment manufacturers (OEMs) and both airline and independent maintenance repair organizations (MRO) shops. The strategy is important, because the sales of systems in the Military world is limited to perhaps ten systems in the immediate future. However, if sufficient cost avoidance and increased safety can be shown in the commercial aircraft community, sales could number well over a hundred systems to facilities that routinely scrap or overhaul critical coated components.