4. Eddy Currents, Techniques and Phenomena
Nuclear acoustic resonance has been studied in cylindrical specimens of polycrystalline aluminum deformed in compression and tension. The acoustic absorption lineshape is found' to be asymmetric and dependent on the amount of deformation. Analysis of the signals in terms of an admixture of the real and imaginary parts of the nuclear susceptibility has been performed. The linewidth measured from the experimental signals varies with deformation exhibiting a minimum between twelve and fifteen percent strain.
Matzkanin, G. A.; Leisure, R. G.; and Hsu, D. K., "Investigation of Nuclear Acoustic Resonance for the Nondestructive Determination of Residual Stress" (1980). Proceedings of the DARPA/AFML Review of Progress in Quantitative NDE, July 1978–September 1979. 13.