Synergistic Diagnostics of Aircraft Materials and Structures

Abstract : This final report summarizes the results obtained with a synergistic measurement system used as the basis of a diagnostic system for monitoring and characterizing aircraft materials and structures. The system utilizes the development of an empirical model describing the characteristics and dynamics of the material or structure. It is demonstrated that this approach is useful for processing the signals of linear as well as non-linear systems. The linear modeler has been used to obtain a characterization of the strength and location of impacts on a truss-like structure. While the more general, automatic modeler which resembles a multi-dimensional, non-parametric regression approach was utilized to locate sources of acoustic emissions in a structure and also to predict fatigue crack growth in Al alloys under different loading conditions. Applications have been to measured as well as existing data which comprise a corrosion-fatigue material property data base. It was found that the prediction performance of the modeler is excellent if the measured input data closely resembles one of the previous data sets residing in the memory. An enhanced predictive performance can be obtained from the modeler if a predictor-corrector algorithm is used.