Hybridization of volumetric and surface models for the computation of the T/R EC probe response due to a thin opening flaw

Abstract

International audienceThe purpose of this paper is to describe the development of simulation tools dedicated to eddy current non destructive testing (ECNDT) on planar structures implying planar defects. Two integral approaches using the Green dyadic formalism are considered. The surface integral model (SIM) is dedicated to ideal cracks, whereas the volume integral method is adapted to general volumetric defects. The authors observed that SIM provides satisfactory results, except in some critical transmitting/receiving (T/R) configurations. This led us to propose a hybrid method based on the combination of the two previous ones. This method enables to simulate ECNDT on planar structures implying defects with a small opening using T/R probes

Rapid computation of eddy current signals from narrow cracks

“…However, problems have been observed due to the large number of elements required across the crack opening. Hence, a hybridized version of the model was presented to tackle this problem [14], instead of following the already presented approach for a narrow crack in [6].…”

“…This field does exist, but since the integrand in (8) and (9) is hypersingular, there is a certain approach followed to obtain the result and consists of treating the singularity in the spatial domain. Other approaches are the regularization of the integral [15,16] or the treatment of the singularity in the frequency domain [7,14], the latter being a procedure that we have not been able to reproduce. When treating the singularity in the spatial domain, there are two distinct methods to get a result: the exclusion volume technique [5,6] and the cancellation method [11].…”

Generalized Method of Moments: A novel framework for analyzing acoustic scattering from complex objects using a locally smooth surface parametrization and adaptive basis spaces

“…The analysis of scattering from complex objects has wide spread applicability, from crack propagation 1,2 to non-destructive evaluation 3,4 to imaging and diagnostic medicine 5,6 to holography 7 to scattering from rough surfaces 8,9 , etc. Boundary integral formulations offer an efficient modality for the analysis of fields scattered by homogeneous objects as (i) they can be formulated only in terms of surface integral equations and (ii) radiation boundary conditions are explicitly included in the Green's function.…”

Computation of a quasi-static field induced by two long straight parallel wires in a conductor with a rough surface

“…The need to develop fast numerical methods for simulating the eddy current non-destructive testing (ECNDT) of conductive test pieces has motivated a great number of research works [1][2][3][4][5][6][7][8] to develop and to implement the volume integral method (VIM) using the Green's dyadic formalism. The advantage of integral approaches lies in the fact that Green's dyads include boundary conditions associated with the geometry of the test piece to be investigated and some analytical expressions of Green's dyads are well known for stratified media and for some canonical geometries such as planar or pure cylindrical geometries [9].…”