216 research outputs found
Time-domain geometric eddy-current A formulation for hexahedral grids
Get PDFpeer reviewedThe aim of this paper is to present a 3-D time-domain eddy-current A formulation based on the discrete geometric approach (DGA) over unstructured and nonorthogonal hexahedral dual grids. The resulting differential algebraic system of equation, solved by means of a singly-diagonally implicit Runge-Kutta (SDIRK) variable step-size solver, leads to very accurate results at reduced computational costs, as shown by numerical analysis
Constitutive matrices using hexahedra in a discrete approach for eddy currents
No full textWe examine the construction of reluctivity and Ohm’s constitutive matrices for discrete geometric approaches using nonregular hexahedra
as primal volumes. The effect of element deformation on the representation of uniform fields have been investigated for static fields.
Then convergence and accuracy of the proposed matrices has been carried out using an eddy-current problem as working example
A perturbation method for the A-chi geometric eddy-current formulation
No full textA perturbation method for the A-χ geometric formulation to solve eddy-current problems is introduced. The proposed formulation is applied to the feasibility design of a non-destructive evaluation device suitable to detect "long" longitudinal flaws in hot steel bars
Coupling Between Circuits and A-\chi Discrete Geometric Approach
No full textWe propose a way to couple field equations for quasistatics in a bounded domain-where electromagnetic phenomena are assumed to be confined-with circuit equations. The algebraic equations describing eddy-current problems are obtained by means of a discrete geometric formulation A-chi, based on the circulation of the magnetic vector potential A and a scalar potential chi
A perturbation method for the T-Ω geometric eddy-current formulation
No full textpeer reviewedA perturbation method for the T-Ω geometric formulation to solve eddy-current problems is introduced. The proposed formulation is applied to the feasibility design of a nondestructive evaluation device suitable to detect “long” longitudinal flaws in hot steel bars
A perturbation method for the T-Omega eddy-current formulation
No full textA perturbation method for the T-\Omega geometric formulation to solve eddy-current problems is introduced. The proposed formulation
is applied to the feasibility design of a nondestructive evaluation device suitable to detect “long” longitudinal flaws in hot steel bars
A non-destructive testing application solved with A-X geometric eddy-current formulation
No full textpeer reviewedPurpose – The purpose of this paper is to introduce a perturbation method for the A-X geometric formulation to solve eddy-current problems and apply it to the feasibility design of a non-destructive evaluation device suitable to detect long-longitudinal volumetric flaws in hot steel bars.
Design/methodology/approach – The effect of the flaw is accurately and efficiently computed by solving an eddy-current problem over an hexahedral grid which gives directly the perturbation due to the flaw with respect to the unperturbed configuration.
Findings – The perturbation method, reducing the cancelation error, produces accurate results also for small variations between the solutions obtained in the perturbed and unperturbed configurations. This is especially required when the tool is used as a forward solver for an inverse problem. The method yields also to a considerable speedup: the mesh used in the perturbed problem can in fact be reduced at a small fraction of the initial mesh, considering only a limited region surrounding the flaw in which the mesh can be refined. Moreover, the full three-dimensional unperturbed problem does not need to be solved, since the source term for computing the perturbation is evaluated by solving a two-dimensional flawless configuration having revolution symmetry.
Originality/value – A perturbation method for the A-X geometric formulation to solve eddy-current problems has been introduced. The advantages of the perturbation method for non-destructive testing applications have been described
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