The probability of detection (POD) of a well-controlled, automated eddy current (EC) procedure
is evaluated in a numerical model and compared with experiments. The procedure
is applied in laboratory environment with a single absolute probe which is positioned for
raster scan over flat surfaces containing fatigue cracks. The variability of the signal amplitude,
due to small fatigue cracks in the Titanium alloy Ti-6Al-4 V, is expected to mainly
originate from crack characteristics and the index distance of the raster scan. The POD
model is based on the signal versus crack size (^a versus a) result. The presented procedure
provides a well-defined basis for a comparison between a simulated and an experimentally
based POD assessment. Finite element analysis is used to model the EC method. A simplified
fatigue crack model is first introduced and evaluated experimentally. Numerical computations
are then used to build the corresponding model-based POD curve which shows
good agreement with the experimental result. The model-based POD curve is generated
both by means of a parametric and a nonparametric approach. Differences between
model-based and experimental POD are discussed as well as the delta POD approach using
transfer functions.
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