3 research outputs found
A robust inversion method for quantitative 3D shape reconstruction from coaxial eddy-current measurements
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