3 December 1993 Detection of subsurface flaws using SQUID eddy current technique
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Subsurface flaws in electrically conducting components are not easy to detect by conventional eddy current techniques because the skin depth (delta) decreases at high frequencies, while the signal decreases at low frequencies. However, SQUID magnetometers are capable of measuring dc and low frequency magnetic fields, and have been used for imaging current distributions. We have now extended SQUID NDE by utilizing a technique to induce an extended eddy current parallel to the surface in a conducting plate. The magnetic field due to the eddy current perturbation caused by a subsurface flaw has been calculated and compared with experimental results, which gives information about the depth of the flaw. We also present data recorded from aluminum samples that simulate lap joints in aircraft wings.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yu Pei Ma, Yu Pei Ma, John P. Wikswo, John P. Wikswo, } "Detection of subsurface flaws using SQUID eddy current technique", Proc. SPIE 2001, Nondestructive Inspection of Aging Aircraft, (3 December 1993); doi: 10.1117/12.163843; https://doi.org/10.1117/12.163843


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