Single voxel approach for Lorentz force evaluation
ISSN: 0332-1649
Article publication date: 1 April 2019
Issue publication date: 3 June 2019
Abstract
Purpose
Lorentz force evaluation is a non-destructive evaluation method for conducting specimens. The movement of a specimen relative to a permanent magnet leads to Lorentz forces that are perturbed in the presence of a defect. This defect response signal (DRS) is used for defect reconstruction. To solve a linear inverse problem for defect reconstruction, an accurate and fast forward computation method is required. As existing forward methods are either too slow or too inaccurate, the purpose of this paper is to propose the single voxel approach (SVA) as a novel method.
Design/methodology/approach
In SVA, the DRS is computed as a superposition of DRSs from single defect voxels, which are calculated in advance, by applying the boundary element source method. This research uses a setup of an isotropic conducting specimen, a spherical permanent magnet and defects of different shapes at different depths. With the help of simulations, this study compares the SVA to the previously proposed approximate forward solution (AFS) and the extended area approach (EAA) using the normalized root mean square error (NRMSE). Simulated data using the finite element method serve as the reference solution.
Findings
SVA shows across all simulations NRMSE values <2.5 per cent compared to <8 per cent for EAA and <12 per cent for AFS.
Originality/value
The superposition principle of SVA allows for the application of linear inverse methods for defect reconstruction while providing sufficient accuracy of the forward method.
Keywords
Acknowledgements
This work has been supported by the Deutsche Forschungsgemeinschaft in the framework of the Research Training Group “Lorentz force velocimetry and Lorentz force eddy current testing” (GRK 1567) and Ha 2899/23-1.
Citation
Dölker, E.-M., Petković, B., Schmidt, R., Ziolkowski, M., Brauer, H. and Haueisen, J. (2019), "Single voxel approach for Lorentz force evaluation", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 38 No. 3, pp. 943-952. https://doi.org/10.1108/COMPEL-09-2018-0354
Publisher
:Emerald Publishing Limited
Copyright © 2019, Emerald Publishing Limited