Life Remaining Prognostics for Airframe Structural Components

Many aircraft structural components, such as attachment fittings and landing gear parts, have very short critical crack lengths and do not lend themselves to state-of-the-art durability and damage tolerance assessments. These small critical crack lengths, and short crack propagation lives, do not allow for safe operational usage intervals for which damage tolerance methods can be applied. Positron systems has completed projects which demonstrated that induced positron analysis (IPA) technologies can reliably detect and quantify tensile plastic strain damage induced by simulated and operational conditions in aerospace material specimens and components. A preliminary functional relationship between total strain and the normalized IPA S parameter has been developed for several aerospace materials. The fatigue testing has demonstrated the IPA technologies have potential to detect fatigue damage induced in specimens and operational components when the loads are large enough to cause plastic deformation.