A robust inversion method for quantitative 3D shape reconstruction from coaxial eddy-current measurements
Résumé
This work is motivated by the monitoring of conductive clogging deposits
in steam generator at the level of support plates. One would like to
use monoaxial coils measurements to obtain estimates on the clogging
volume. We propose a 3D shape optimization technique based on simplified
parametrization of the geometry adapted to the measurement
nature and resolution. The direct problem is modeled by the eddy current approximation
of time-harmonic Maxwell's equations in the low frequency regime. A
potential formulation is adopted in order to easily handle the complex
topology of the industrial problem setting. We first characterize the
shape derivatives of the deposit impedance signal using an adjoint field technique. For the
inversion procedure, the direct and adjoint
problems have to be solved for each coil vertical position which is
excessively time and memory consuming. To overcome this difficulty, we propose and discuss a
steepest descent method based on a fixed and invariant
triangulation. Numerical experiments are presented to illustrate the convergence and the efficiency of the method.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...