Measurement-based prognostic models for service-induced damage in turbine engine components

Development of reliable performance life remaining prognostic models for aircraft turbine engine components such as disks and blades requires accurate diagnostic methods to measure integrated damage effects with uncertainties. Photon induced positron annihilation (PIPA) and related technologies have demonstrated the capability to accurately and quantitatively measure operational damage accumulation in turbine engine components that can be used to develop mechanistic failure models that would be applicable to current engine prognostic models. Quantitative failure models for operational components that are based on the PIPA measurement data are expected to have a high degree of accuracy and provide suitable statistical data on the likelihood of failure for any given period of operation. Results of PIPA studies performed as part of National Science Foundation and other studies that assess the relative effects of surface treatments, temperature, fatigue, and thermomechanical damage on nickel based superalloy components indicate that damage effects in turbine engine components can be quantified and incorporated in appropriate life remaining models.