ESTIMATION OF CRACK DEPTHS IN ALUMINUM PLATES USING UNIFORM SURFACE EXCITATION AND GMR DETECTION
Ribeiro, A. L.
ESTIMATION OF CRACK DEPTHS IN ALUMINUM PLATES USING UNIFORM SURFACE EXCITATION AND GMR DETECTION, Proc RELACRE - Conferência Nacional em Ensaios Não Destrutivos - CNEND, Évora, Portugal, Vol. Pen Drive, pp. ST1 - ST6, December, 2017.
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This work presents a method to determine the depth of cracks in aluminium plates using the eddy current method. Three types of excitation have been compared, namely sinusoidal single frequency excitation with frequencies covering a bandwidth compatible with the standard depths of penetration up to the plate thickness. The second method is a multi-frequency excitation with all the frequencies applied simultaneously and covering the same bandwidth as used in the first method. Finally, in a third method, gaussian white noise is used as excitation, also covering the same bandwidth. The method is used to detect both surface and subsurface cracks.