Wireless In-situ Nondestructive Inspection of Engine Rotor Disks with Ultrasonic Guided Waves

The structural integrity of jet engine turbine or fan rotor disks is vital for aviation safety. Cumulative cracks at critical loading and high stress areas, if not detected and repaired in time, may lead to catastrophic failure. Traditional methods such as Fluorescent Penetrant Inspection (FPI) and eddy current are limited to point-by-point measurement and are very time consuming. Disassembly of the engine is required for each inspection, which in turn may cause maintenance induced problems. We propose a wireless in-situ ultrasonic guided wave health monitoring approach. It applies light, thin, high temperature leave-in-place ultrasonic guided wave circumferential patch transducers around the root of the disk, and a pair of innovative tube antennae that wirelessly couple the transducers to the inspection instruments. Guided waves travel in the disk for crack inspection, and the inspection could be done even when the disk is rotating. Phase I results clearly demonstrate that the guided wave is very sensitive to tiny cracks on a rotating aluminum disk, and the tube antennae worked well. The envisioned system can inspect a relatively large area, has minimal effect on the rotor performance, instantaneously provides reliable and quantitative data such as crack location and severity level, and minimize and eventually eliminate the need for structural disassembly.