Damage Detection in Complex Fastened Joints

Rotorcraft have been at the forefront of Condition Based Maintenance (CBM) technologies. For nearly 20 years, Heath & Usage Monitoring Systems (HUMS) have been used on rotorcraft such as the H-60, CH-53E, H-1 and V-22 to collect prognostic data to reduce preventative maintenance costs and increase asset availability. The majority of the HUMS data collected today relates to drive system components, such as monitoring vibration off gears, bearings, shafts and rotors. The vast majority of HUMS were developed by Goodrich (now part of UTAS). The proposed technology would expand HUMS hardware to be able to also capture fatigue damage in complex fastened joints. Many Structural Health Monitoring (SHM) systems in development can detect damage on flat structure, but features hidden in a multi-layer stack can be extremely challenging for conventional technologies. Multiple approaches for addressing this problem will be investigated in this program, each within the concept of using a distributed beamforming array with the fasteners themselves being the sensor elements. By exciting the fasteners directly, more energy will penetrate into the complex joints, thus making it easier to discover hidden damage. Integration with UTAS HUMS hardware will also be addressed.