Wally Hoppe

EDDY CURRENT ASSESSMENT OF ENGINEERED COMPONENTS CONTAINING NANOFIBERS

The eddy current approach has been used to assess engineered components containing nanofibers. Five specimens with different programmed defects were fabricated. A 4‐point collinear probe was used to verify the electrical resistivity of each specimen. The liftoff component of the eddy current signal was used to test two extreme cases with different nano contents. Additional eddy current measurements were also used in detecting a missing nano layer simulating a manufacturing process error. The results of this assessment suggest that eddy current liftoff measurement can be a useful tool in evaluating the electrical properties of materials containing nanofibers.

An Update on Automatic Positioning, Inspection, and Signal Processing Techniques in the RFC/NDE Inspection System

This paper updates several techniques developed for the Retirement For Cause (RFC) Nondestructive Evaluation (NDE) Inspection System eddy current inspection module. Techniques to be discussed include: 1. Scallop Centering — development of an automatic scallop centering routine makes scallop inspections reliable. 2. Soft Survey Mode — improvements have been made for fast peak detection. 3. Method 2 Select Mode — a fine flaw detection technique based on the acquired waveform. 4. Antirotation Window Inspection — a frequency select mode has been established for detecting flaws in antirotation windows. 2. Scaling of Flaw Depth — a scaling factor has been developed, based on Phase I Reliability Test data, which converts flaw signal amplitude into estimated flaw depth.