Advanced Field-Use Instrument for Nondestructive Fatigue Damage Assesment and Remaining Service Life Prediction for Aging Aerospace Systems

During Phase I, we will develop the technology for a field use instrument to determine the residual stress, fatigue damage and remaining service life for aging metal structures. The technology will be based on a state-of -the-art wide-angle x-ray detector recently developed at ATMI. The life span estimation will use the measured micro-defect density to compare to a paramedic life span map based on the alloy composition, residual stress and loading conditions. The map will be based on the structural change of diffraction peaks form multiple individual grains during the course of fatigue life. We will demonstrate the feasibility of rapid fatigue damage determination for representative materials by testing representative samples of the three most common crystal cell structures for engineering metals, making the technology applicable for steels, aluminum, nickel and titanium alloys The samples will undergo high circle teensy/compression, bending and corosion loading. Validation of the life span map will be accomplished by interrupting high cycle fatigue tests, predicting remaining life, and subsequently cycling the sample to failure. Successful completion of the Phase I effort will culminate in the production of a field use instrument to be built and delivered at the completion of the Phase II program.