Maturation of a Guided Wave-based Damage Detection System for Ageing Aircraft

ABSTRACT: The Metis Design Corporation (MDC) has developed a structural health monitoring (SHM) system to monitor damage in aircraft material with minimal manual intervention. During Phase I, MDC focused on pattern recognition-based algorithms, demonstrating detection of damage, discerning different damage types, and estimating severity. The original Phase II effort focused on the development of lightweight hardware capable of facilitating both acoustic emission and guided wave methods. Further, MDC validated the previously developed SHM algorithms using fatigued titanium lugs. During this Phase II extension, MDC seeks to increase the system maturity such that it can be considered for deployment within ASIP. Tasks will focus on identification of gaps that exist preventing transition into fielded applications. This includes determining applicable airworthiness criterion and condition levels, and a thorough business case analysis (BCA) to rank parts with the highest anticipated return. A focus will be on analytical and experimental optimization for best components as identified by the BCA, along with establishing preliminary detection statistics necessary to be considered under ASIP. An operational concept will be developed for how such a system would be maintained at the ALC. Finally, a gap analysis will detailing what remains and at what cost to fully field the system. BENEFIT: SHM technologies have the potential for many economic benefits in a broad range of commercial and defense markets. These systems find utilization within structures ranging from military or civil aircraft, to cars, ships or spacecraft. The first major benefit is that health monitoring eliminates the need for scheduled inspections. A second major economic benefit is that a continuously monitoring system would allow for the use of the much more efficient condition based maintenance (CBM) design methodology of a structure, otherwise known as need-based repair. A third benefit is the increased service time of the structure. Finally, an SHM system could have a significant financial impact if it is able to detect the need for maintenance before a catastrophic failure, potentially saving lives and a costly vehicle. Airlines that chose to use these systems would be able to reduce the quantity and duration of required inspections, giving them the opportunity cost to capture profit due to more up-time. Another important aerospace market would be to facilitate launch/no-launch decisions for expendable launch vehicles (ELV), and enable quick turn around times for reusable launch vehicles (RLV). One of the key factors to the marketability of this damage detection patch is its versatility, the potential for integration into not just new applications, but existing systems as well. The first obvious target is the military sector, where one of these systems can reduce the manpower needed for inspection, as well as up to 30% of the maintenance costs. Additional commercial and space market opportunities exist for the application of reliable damage detection. These systems can reduce the quantity and duration of airline aircraft inspections, reduce the weight and increase the fuel efficiency of aircraft, and facilitate launch/no-launch decisions for spacecraft. This will likely be a critical technology for future reusable launch vehicles as well. Initially these products will be marketed towards the air and space industry, but eventually will be more broadly diffused into naval, automotive and civil infrastructure applications.