scholarly journals A three-dimensional inverse finite-element method applied to experimental eddy-current imaging data

2006 ◽  
Vol 42 (5) ◽  
pp. 1560-1567 ◽  
Author(s):  
M. Soleimani ◽  
W.R.B. Lionheart ◽  
A.J. Peyton ◽  
Xiandong Ma ◽  
S.R. Higson
Author(s):  
Karl Hollaus

Purpose The simulation of eddy currents in laminated iron cores by the finite element method (FEM) is of great interest in the design of electrical devices. Modeling each laminate by finite elements leads to extremely large nonlinear systems of equations impossible to solve with present computer resources reasonably. The purpose of this study is to show that the multiscale finite element method (MSFEM) overcomes this difficulty. Design/methodology/approach A new MSFEM approach for eddy currents of laminated nonlinear iron cores in three dimensions based on the magnetic vector potential is presented. How to construct the MSFEM approach in principal is shown. The MSFEM with the Biot–Savart field in the frequency domain, a higher-order approach, the time stepping method and with the harmonic balance method are introduced and studied. Findings Various simulations demonstrate the feasibility, efficiency and versatility of the new MSFEM. Originality/value The novel MSFEM solves true three-dimensional eddy current problems in laminated iron cores taking into account of the edge effect.


Author(s):  
Brian H. Dennis

The direct measurement of temperatures and heat fluxes may be difficult or impossible on boundaries that are obstructed, such as internal cavities, or exposed to harsh environmental conditions that would destroy the thermal sensors. In such circumstances, one may inversely determine the temperature and heat fluxes on these unknown boundaries by using over-specified conditions on boundaries where such information can be readily collected. This assumes the geometry and material properties of the domain are known. Algorithms for solving these problems, such those based on finite difference, finite element, and boundary element, are well known for the case where measured boundary conditions are not a function of time. In this work, I demonstrate an inverse finite element method that effectively solves this inverse heat conduction problem using over-specified temperatures and heat fluxes that are time varying. The material properties may highly heterogeneous and non-linear. A boundary regularization method in space and time is used to stabilize the method for cases involving errors in temperature and heat flux measurements. Several three dimensional examples are given using simulated measurements with and without measurement errors, to demonstrate the accuracy of the method.


1990 ◽  
Vol 18 (4) ◽  
pp. 216-235 ◽  
Author(s):  
J. De Eskinazi ◽  
K. Ishihara ◽  
H. Volk ◽  
T. C. Warholic

Abstract The paper describes the intention of the authors to determine whether it is possible to predict relative belt edge endurance for radial passenger car tires using the finite element method. Three groups of tires with different belt edge configurations were tested on a fleet test in an attempt to validate predictions from the finite element results. A two-dimensional, axisymmetric finite element analysis was first used to determine if the results from such an analysis, with emphasis on the shear deformations between the belts, could be used to predict a relative ranking for belt edge endurance. It is shown that such an analysis can lead to erroneous conclusions. A three-dimensional analysis in which tires are modeled under free rotation and static vertical loading was performed next. This approach resulted in an improvement in the quality of the correlations. The differences in the predicted values of various stress analysis parameters for the three belt edge configurations are studied and their implication on predicting belt edge endurance is discussed.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1388
Author(s):  
Daniele Oboe ◽  
Luca Colombo ◽  
Claudio Sbarufatti ◽  
Marco Giglio

The inverse Finite Element Method (iFEM) is receiving more attention for shape sensing due to its independence from the material properties and the external load. However, a proper definition of the model geometry with its boundary conditions is required, together with the acquisition of the structure’s strain field with optimized sensor networks. The iFEM model definition is not trivial in the case of complex structures, in particular, if sensors are not applied on the whole structure allowing just a partial definition of the input strain field. To overcome this issue, this research proposes a simplified iFEM model in which the geometrical complexity is reduced and boundary conditions are tuned with the superimposition of the effects to behave as the real structure. The procedure is assessed for a complex aeronautical structure, where the reference displacement field is first computed in a numerical framework with input strains coming from a direct finite element analysis, confirming the effectiveness of the iFEM based on a simplified geometry. Finally, the model is fed with experimentally acquired strain measurements and the performance of the method is assessed in presence of a high level of uncertainty.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1421
Author(s):  
Michał Szulborski ◽  
Sebastian Łapczyński ◽  
Łukasz Kolimas ◽  
Łukasz Kozarek ◽  
Desire Dauphin Rasolomampionona ◽  
...  

In this paper, a detailed three-dimensional, transient, finite element method of fuse link NH000 gG 100 A is proposed. The thermal properties during the operation of the fuses under nominal (100 A) and custom conditions (110 and 120 A) are the main focus of the analyses that were conducted. The work concerns both the outside elements of the fuse link (ceramic body) and the elements inside (current circuit). Both the distribution of the electric current and its impact on the temperature of the construction parts of the fuses during their operating mode have been described. Temperature distribution, power losses and energy dissipation were measured using a numerical model. In order to verify and validate the model, two independent teams of scientists executed experimental research, during which the temperature was measured on different parts of the device involving the rated current. Finally, the two sets of results were put together and compared with those obtained from the simulation tests. A possible significant correlation between the results of the empirical tests and the simulation work was highlighted.


2020 ◽  
Vol 17 (3) ◽  
pp. 349-360
Author(s):  
Xiang-Zhong Chen ◽  
Yun-He Liu ◽  
Chang-Chun Yin ◽  
Chang-Kai Qiu ◽  
Jie Zhang ◽  
...  

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