Industrial Age non-destructive evaluation to Information Age structural health monitoring

This article was originally presented as a keynote address at the Ninth International Workshop on Structural Health Monitoring with the intent of provoking discussions relating to the transformation of aircraft maintenance practices by exploiting opportunities and benefits offered by Information Age technology and techniques. The US Air Force currently manages its aircraft using a schedule-based maintenance philosophy. This schedule-based approach works well for ensuring aircraft integrity; however, it is very costly, labor-intensive, and reduces aircraft availability. Structural health monitoring systems have the potential to analyze near-real-time and historical weapon systems data to provide a predictive maintenance capability. However, much aerospace structural health monitoring research has focused on in situ structural inspection techniques instead of structural monitoring. Structural inspections typically entail examining key locations of an airframe for material degradation or flaws. These examinations usually occur at predefined time intervals. As such, each inspection is considered an independent evaluation. Conversely, structural monitoring involves continuous condition surveillance of an airframe over an extended period of time. Structural monitoring uses past conditions and expected future conditions for producing a comprehensive understanding of the current health state. A new architecture, Cognitive Architecture for State Exploitation, is introduced as a monitoring technique that combines diagnostic or state (i.e. health) assessments, prognostic assessments, and mission objectives into a common framework to enable goal-based decision making. Results from a laboratory experiment are utilized to demonstrate the application of Cognitive Architecture for State Exploitation and to illustrate the potential to improve effectiveness and efficiency metrics compared to those of the current US Air Force maintenance procedures.