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Efficient finite element assembly of high order Whitney forms Marsic, Nicolas ; Geuzaine, Christophe in IET Science, Measurement & Technology (2015), 9(2), 204-210 This study presents an efficient method for the finite element assembly of high order Whitney elements. The authors start by reviewing the classical assembly technique and by highlighting the most time ... [more ▼] This study presents an efficient method for the finite element assembly of high order Whitney elements. The authors start by reviewing the classical assembly technique and by highlighting the most time consuming part. Then, they show how this classical approach can be reformulated into a computationally efficient matrix-matrix product. They also address the global orientation problem of the vector valued basis functions. They conclude by presenting numerical results for a three-dimensional wave propagation problem. [less ▲] Detailed reference viewed: 74 (28 ULg)h- and a-Formulations for the Time-Domain Modelling of Thin Electromagnetic Shells V Sabariego, Ruth ; Geuzaine, Christophe ; Dular, Patrick et al in IET Science, Measurement & Technology (2008), 2(6), 402-408 Thin conductive magnetic shells are accounted for by means of two different time-domain magnetodynamic finite-element formulations, namely the magnetic field formulation and the magnetic vector potential ... [more ▼] Thin conductive magnetic shells are accounted for by means of two different time-domain magnetodynamic finite-element formulations, namely the magnetic field formulation and the magnetic vector potential formulation. Both approaches are an extension of the classical linear frequency-domain thin-shell approximation. The interface conditions for the magnetic field formulation and the vector potential formulation are expressed in terms of the average current density and the average flux density, respectively, together with a number of higher-order components of these quantities. The proposed time-domain thin-shell approaches are validated by means of a 3D magnetodynamic problem. The results are shown to agree well with those obtained with a fine model, whereas the computation time is significantly reduced. [less ▲] Detailed reference viewed: 30 (1 ULg)Perturbation finite-element method for magnetic circuits Dular, Patrick ; V Sabariego, Ruth ; et al in IET Science, Measurement & Technology (2008), 2(6), 440-446 Accurate magnetic flux distributions are calculated in magnetic circuits via a subproblem finite-element (FE) method based on a perturbation technique. An approximate FE problem considering ideal flux ... [more ▼] Accurate magnetic flux distributions are calculated in magnetic circuits via a subproblem finite-element (FE) method based on a perturbation technique. An approximate FE problem considering ideal flux tubes is first solved. It gives the source for FE perturbation problems considering the flux tubes with their exterior regions, accounting thus for leakage fluxes, as well as for changes of material properties and shapes. The proposed technique aims to accurately quantify the gain given by each model refinement on both local fields and global quantities and to justify the usefulness of this refinement. It is also well adapted to parameterised analyses on geometrical and material data. [less ▲] Detailed reference viewed: 18 (1 ULg)Near-field coupling of wireless devices and long communications cables ; Zhang, Yinghong ; et al in IET Science, Measurement & Technology (2008), 2(1), 18-24 A comprehensive investigation of the coupling between mobile devices and communication/control cables in several environments is described here. Both experimental and numerical results are shown and ... [more ▼] A comprehensive investigation of the coupling between mobile devices and communication/control cables in several environments is described here. Both experimental and numerical results are shown and compared using a number of different methods in different laboratories. Results indicate a good level of agreement between the different approaches thus giving confidence that predictive studies based on simulation can give a good quantitative assessment of coupling. Moreover, the studies show that varying the configuration of the coupled systems does not significantly affects the maximum coupling thus making it possible to obtain a reasonable worst case estimate of coupling from a small number of generic studies. [less ▲] Detailed reference viewed: 77 (9 ULg)Electromagnetic compatibility analysis of unstructured mains networks for high-speed data transmission: Part 1 ; ; et al in IET Science, Measurement & Technology (2008), 2(3), 146-153 Different approaches for the characterisation of relevant parameters of the low-voltage mains network, used for high-speed data transmission (BPL, broadband over power line) are described. Part 1 of the ... [more ▼] Different approaches for the characterisation of relevant parameters of the low-voltage mains network, used for high-speed data transmission (BPL, broadband over power line) are described. Part 1 of the paper depicts the disturbance scenario of these BPL devices and the motivation will be given for the development of a new measurement procedure in CISPR for the estimation of the high-frequency characteristics of AC mains network. The improvements of the measurement method is not restricted to BPL applications, but can also be applied to other wire-based telecommunication systems. Part 2 of the paper shows the definitions and comparisons of different symmetry factors. The transfer of the results on the compliance test for BPL devices will be shown. [less ▲] Detailed reference viewed: 54 (0 ULg)Electromagnetic compatibility analysis of unstructured mains networks for high-speed data transmission: Part 2 ; ; et al in IET Science, Measurement & Technology (2008), 2(3), 154-159 Different approaches are described for the characterisation of the low voltage mains network that is used for high-speed data transmission broadband over power line (BPL). Part 1 investigated the ... [more ▼] Different approaches are described for the characterisation of the low voltage mains network that is used for high-speed data transmission broadband over power line (BPL). Part 1 investigated the disturbance scenario of these BPL devices and importance will be given to develop a new measurement procedure in Comite Internationale Special des Perturbations Radioelectrotechnique (CISPR) to estimate the high-frequency characteristics of AC mains networks. The improvements of the measurement method that can also be applied to other wire-based telecommunication systems will also be presented. Part 2 shows the definitions and comparisons of different symmetry factors. The transfer of the results on the compliance test for BPL devices will also be depicted. [less ▲] Detailed reference viewed: 64 (0 ULg)Perturbation technique for the finite element modelling of differential probes in non-destructive eddy-current testing V Sabariego, Ruth ; Dular, Patrick in IET Science, Measurement & Technology (2007), 1(1), 25-29 The paper deals with a new finite element scheme for non-destructive eddy-current testing (ECT) problems involving multiply connected test pieces and differential probes. It concerns a perturbation ... [more ▼] The paper deals with a new finite element scheme for non-destructive eddy-current testing (ECT) problems involving multiply connected test pieces and differential probes. It concerns a perturbation technique applied to the magnetodynamic h - phi formulation. The unperturbed field (in the absence of the flaw) is conventionally computed in the complete domain. The source of the perturbation problem is then determined by the projection of the unperturbed field in a relatively small region around the defect, the optimum size of which depends on the working frequency. The discretisation of this reduced domain is well adapted to the size of the defect and chosen independently of the dimensions of the excitation probe and the specimen under study. At a discrete level, the voltage change is efficiently computed by integration only over the defect and a layer of elements in the reduced domain that touches the defect's boundary. The accuracy of the proposed perturbation model is illustrated by comparison of the results obtained for different dimensions of the reduced domain with those achieved in the conventional way. The considered test case involves a differential probe scanning the outer surface of a metal tube for the detection of through-wall cracks. [less ▲] Detailed reference viewed: 23 (2 ULg)Finite element modelling of ion convection by electrostatic forces Deliège, Geoffrey ; ; et al in IET Science, Measurement & Technology (2004), 151(6), 398-402 Detailed reference viewed: 5 (2 ULg) |
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