SIPS, A Structural Integrity Prognosis System

The Structural Integrity Prognosis System (SIPS) is being designed to provide prompt, informed predictions of the structural viability of individual assets based on tracking of their actual use and modeling of anticipated usage. The prognosis system is founded on a collaboration between sensor systems, advanced reasoning methods for data fusion and signal interpretation, and modeling and simulation systems. The modeling approach is based on the physical mechanisms of corrosion and fatigue damage. This paper will present an overview of the system and present recent results of laboratory testing of fatigue coupons that were representative of a typical aircraft lower wing structure. During the tests, several novel sensor systems were used to detect and quantify fatigue damage. The sensor output was combined with results from several models of fatigue damage. The models were based on the microstructural origins of fatigue, and included statistical distributions of important microstructural parameters. The models and the sensor data were combined in a prognosis system, and used to predict the outcome of the fatigue tests.. Uncertainty in the sensor data and uncertainty in the various models and their microstructural inputs was explicitly dealt with in the prognosis system. The predictions were compared to post-mortem analysis of cracking in the broken samples.