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Carbon Nanotube Appliques for Fatigue Crack Diagnostics

S. S. KESSLER, G. THOMAS, M. BORGEN, C. T. DUNN

Abstract


The present research targets hot-spot monitoring for ageing aircraft. The sensor itself is a sheet of CNT sandwiched between two electrically isolating adhesive layers. Any growth of flaw would disrupt the CNT electrical network, therefore increasing the network resistance. This effect would be accentuated if the flaw actually tears through the CNT patch, however since the CNT is piezoresistive, even damage growing under the patch would be measured due to the effective residual strain imparted. Using orthogonal parallel pairs of electrodes, one would be able to not only measure extent of a crack, but also deduce the orientation based on relative changes seen by each pair; a flaw growing towards an electrode would have a small effect, while growing parallel to an electrode pair would offer a significant measured change. Analytical results are presented along with experimental data for calibrated simulated crack growth in addition to actual fatigue crack growth in aluminum specimen.

doi: 10.12783/SHM2015/207


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