Engineering Appraisal of SwRI Magnetic Crack Definer Applied to CH-47Rotor Blades:Verification Addendum.

摘要

This addendum effort evaluates the Magnetic Crack Definer (MCD) and an ultrasonics system on CH-47helicopter rotor blade spars to determine the capabilities for detecting fatigue cracks under the ferromagnetic steel doubler plates and to determine possible sources of false alarms. Although attempts to adapt the MCD to doubler plates were unsuccessful, a supplementary ultrasonics procedure developed during the program can inspect all spar material in the doubler regions. The remaining outboard regions were inaccessible to ultrasonics due to overlaying materials. These outboard regions are accessible,however,to the MCD which accommodates as much as 0.1inch of lift-off due to nonferromagnetic overlays. (Modified author abstract)