Inversion of Eddy - Current Data via Conjugate Gradients
نویسنده
چکیده
In a companion paper, [1], we developed a rigorous, nonlinear model for inverting eddy-current data by means of the conjugate gradient algorithm. In this paper we will present some results obtained from the linearized version of the rigorous model. In this version we assume that the electric field within the flaw is simply the incident field that exists in the absence of the flaw. Hence, if we make this assumption in the multifrequency model of [1] (which is equation (7)(b) of [1]), we derive the linearized multifrequency model for inversion
منابع مشابه
A Multi-frequency Eddy Current Inversion Method for Characterizing Conductivity Gradients on Water Jet Peened Components
This paper describes a multi-frequency eddy current inversion procedure for characterizing specimens that are water jet peened. Multi-frequency inductance data was obtained by using well-characterized eddy current probes. The inversion uses a multi-layer axi-symmetric finite element model as the forward model and the conductivity of each layer is found through interpolation of the inductance-co...
متن کاملNonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion
We investigate a new algorithm for computing regularized solutions of the 2-D magnetotelluric inverse problem. The algorithm employs a nonlinear conjugate gradients (NLCG) scheme to minimize an objective function that penalizes data residuals and second spatial derivatives of resistivity. We compare this algorithm theoretically and numerically to two previous algorithms for constructing such “m...
متن کاملEddy-current probe impedance due to a volumetric flaw
Eddy current induced in a metal by a coil carrying an alternating current may be perturbed by the presence of any macroscopic defects in the material, such as cracks, surface indentations, or inclusions. In eddy-current nondestructive evaluation, defects are commonly sensed by a change of the coil impedance resulting from perturbations in the electromagnetic field. This paper describes theoreti...
متن کاملQUALITY CONTROL OF PRECIPITATION HARDENED ALUMINIUM ALLOY PARTS VIA EDDY-CURRENT NONDESTRUCTIVE EVALUATION
Precipitation hardening is the most common method in the strengthening of aluminium alloys. This method relies on the decrease of solid solubility with temperature reduction to produce fine precipitations which impede the movement of dislocations. The quality control of aluminium alloy specimens is an important concern of engineers. Among different methods, non-destructive techniques are the...
متن کاملElectromagnetic Nondestructive Test (ENDT) Data Inversion by a Neural Network Approach
|With this paper we aim at presenting a neural based approach to conductivity distribution reconstruction by eddy current (EC) data inversion. Keywords| Electromagnetic non-destructive test, Eddy current inspection, Maximum-likelihood data inversion. I. Numerical determination of variation in
متن کامل