M. A. Johnson, Iowa State University, Ames, IA

Summary:

The ACPD approach has been adopted as an alternative to more conventional eddy-current measurements for the characterization of residual stress in turbine engine materials. The basic premise is that the simplified measurement geometry inherent to ACDP will lead to less measurement variability and therefore results that are more quantitative. A high-frequency (up to 100 MHz) current injection and detection system has been developed and is currently undergoing testing to determine the effectiveness of the approach for characterization of near-surface residual stress profiles . In parallel, finite-element models have been developed in order to predict the ACPD response due to different surface conditions. These models will be used to assist in the interpretation of measurement data.