Quantitative Damage Detection Measurements and Performance Life Remaining Determination for Aircraft Structural Materials Using Photon Induced Positro

Damage detection in aircraft structural components is a critical issue, particularly with the increased lifetimes expected from aging aircraft. Development of a reliable inspection technology that can assess current damage levels and remaining performancelife for aircraft components requires methods that can accurately and quantitatively determine damage accumulation and remaining life at any point in the failure progression. With accurate data on damage accumulation, the failure progression can bedefined with known uncertainties. These data can then be incorporated into prognostic models and used to predict the risk of failure at any point in the life of the component and probability of failure prior to next inspection. Positron Systems' PhotonInduced Positron Annihilation (PIPA) process has been demonstrated to quantify damage levels in airframe components and will be used to detect damage build-up in multilayer structural components that have been subjected to various levels of operationaldamage. Although this solicitation calls for investigation using nonlinear acoustic techniques, the PIPA technology provides a number of capabilities that can be expected to provide improved data on quantitative damage buildup with uncertainties; atlevels well below current NDI methods. Development of this technology will have broad applications in military-based and commercial industries. Completion of this research program is believed to have broad anticipated benefits and potential commercialapplications. The benefits of this research range from developing a better understanding of operational damage accumulation and crack growth mechanisms in aerospace materials, to improved useful life predictions and models that can be used to extend thelife of aircraft components; with accurate prognostic estimates of when potential failure might occur, and when the component should be removed from service based on accurate risk-based estimates of when failure might occur derived from the improved dataprovided from PIPA.Commercial applications of this research are as broad as the benefits as it is believed that PIPA technology and its applications in the areas of aging aircraft, maintenance reduction, extended life and reliability could conceivably and significantlychange the entire industry. In addition, this technology will improve aircraft and personnel safety, and lower long-term cost. It is anticipated that the improvements in safety and the potential reduction in catastrophic failures of aircraft componentsalone justifies the research and development of potential applications.