Abstract
The present study explores the capability of COMSOL Multiphysics, as a finite element modelling (FEM) tool, to model the interaction between a split-D differential surface eddy current (ECT) probe and semi-elliptical surface electrical discharge machined (EDM) notches. The effect of the small probe’s lift-off and tilt on its signal is investigated through modelling and subsequently, the simulation outcomes are validated using the probe’s impedance measurements. In the next stage, an adaptive neuro-fuzzy inference system (ANFIS) is designed to take the signal features as inputs and consequently, provide the length of the scanned notch as the system’s output. The system is trained by extracted features of thirty model-generated signals obtained from scanning of the same number of semi-elliptical notches by means of the split-D probe. The trained ANFIS is tested afterwards using the measured signals of 3 calibration EDM notches together with 5 model-based ones. A very low average estimation error is observed with regard to the length estimation of the test notches and the accuracy of the length estimation is found to be quite reasonable.
Highlights
Depending on the configuration of eddy current testing (ECT) probes, diverse analytical and semi-analytical models have been in use to study the interaction of these probes with surface and near surface flaws
In the present study, Finite element modelling (FEM) is exclusively used to compute the impedance of a split-D probe as it scans over 30 semi-elliptical electrical discharge machined (EDM) notches with different dimensions in order to form a size dependent signal archive
It is noted that semielliptical EDM notches are used to generate impedance trajectories since they can fairly be representative of surface fatigue cracks in terms of the shape [7]
Summary
Soft computing has been in use in the field of flaw characterization and classification using ECT signals for a while [13,14,15] Among all these approaches, neural networks (NN) and fuzzy logic (FL) are frequently used together either in series or as an integration to form hybrid systems in which the reasoning and inference power of the FL can be complemented by adaptive learning nature of NN. In the present study ECT signals of the probe scanning over thirty notches with diverse lengths are obtained through FEM simulations in COMSOL Multiphysics® Afterwards, their signals are post-processed to extract the features which are fed as inputs to an ANFIS for training purposes.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
