Damage and Usage Monitoring for Vertical Flight Vehicles

The capability to monitor damage and local stresses on critical components of rotorcraft and vertical-lift aircraft is addressed. This paper describes three different technological innovations that introduce new capabilities: (1) mapping and tracking of damage using high-resolution, eddy-current imaging in a scanning mode, (2) monitoring with on-board networks of sensors for direct detection and characterization of fatigue and corrosion damage, using portable data acquisition units to plug-in and record inspection data in difficult-to-access locations, and (3) on-board, real-time dynamic stress monitoring with networks of magnetic stress gages. The MWM®-Array (eddy current) sensor technology has been demonstrated to be suitable for each of these modes of damage and usage monitoring. The key novel features of this sensor technology are (1) the design of winding constructs that provide predictable sensor responses without requiring control of sensor temperature, lift-off (proximity), or the need for mechanical load transfer to the sensor (i.e., they can operate through coatings and even without contact), and (2) the use of physics-based model generated databases (called measurement grids and lattices) to provide real-time imaging/monitoring of absolute material properties, and robust calibration and self-diagnostics. These efforts have been funded by a combination of NAVAIR, DARPA, and JENTEK IR&D funding over several years. Numerous coupon, component, and even full scale tests have been completed, and funding for installation on two high-time Navy aircraft is in place. This presentation will describe the underlying technology and the demonstrated capabilities, as well as the planned initiatives for transition.