Development of Giant Magnetoresistive inspection system for detection of deep fatigue cracks under airframe fasteners

A redesign of the NASA Langley Research Center developed Giant Magnetoresistive-based Rotating Probe System has been performed based upon experimental and finite element analyses. The resulting probe footprint has been greatly reduced without significantly affecting the depth of detection of the device. Electronics for the probe drive and signal detection circuitry have also been updated. The new electronics deliver variable phase outputs for drive and feedback signals and produces high gain at flaw detection frequencies. The complete system configuration is presented, along with results for the detection of fatigue cracks in sub-layer airframe components.