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Finite Element Mesh Adaptation Strategy From Residual and Hierarchical Error Estimators in Eddy Current Problems Dular, Patrick ; ; et al in IEEE Transactions on Magnetics (2015), 51(3), A strategy of mesh adaptation in eddy current finite element modeling is developed from both residual and hierarchical error estimators. Wished distributions of element sizes of adapted meshes are ... [more ▼] A strategy of mesh adaptation in eddy current finite element modeling is developed from both residual and hierarchical error estimators. Wished distributions of element sizes of adapted meshes are determined from the element-wise local contributions to the estimators and define constraints for the mesh generator. Uniform distributions of the local error are searched. [less ▲] Detailed reference viewed: 10 (0 ULg)A finite element method for poro mechanical modelling of geotechnical problems using local second gradient models Collin, Frédéric ; ; Charlier, Robert in International Journal for Numerical Methods in Engineering (2006), 65(11), 1749-1772 In this paper, a new finite element method is described and applied. It is based on a theory developed to model poromechanical problems where the mechanical part is obeying a second gradient theory. The ... [more ▼] In this paper, a new finite element method is described and applied. It is based on a theory developed to model poromechanical problems where the mechanical part is obeying a second gradient theory. The aim of such a work is to properly model the post localized behaviour of soils and rocks saturated with a pore fluid. Beside the development of this new Coupled theory, a corresponding finite element method has been developed. The elements used are based on a weak form of the relation between the deformation gradient and the second gradient, using a field of Lagrange multipliers. The global problem is solved by a system of equations where the kinematic variables are fully coupled with the pore pressure. Some numerical experiments showing the effectiveness of the method ends the paper. Copyright (c) 2005 John Wiley [less ▲] Detailed reference viewed: 107 (12 ULg)A finite element method for thermomechanical simulation of materials submitted to high strain rates with an implicit approach Jeunechamps, Pierre-Paul ; Ponthot, Jean-Philippe in 7th National Congress on Theoretical and Applied Mechanics (2006) Detailed reference viewed: 17 (1 ULg)Finite element model for the extension of the direct strength method to hot-rolled profile cross-sections Li, Yongzhen ; Rossi, Barbara in Proceedings of the 12th Nordic Steel Construction Conference (2012, September 05) Abstract: In the present research, a geometrically and materially nonlinear analysis using the FE method has been conducted to evaluate the resistance of axially compressed hot-rolled H profile cross ... [more ▼] Abstract: In the present research, a geometrically and materially nonlinear analysis using the FE method has been conducted to evaluate the resistance of axially compressed hot-rolled H profile cross-sections. The FE model was firstly duly verified against experimental data and then used to carry a parametric analysis. The goal of the analysis is to propose a new Direct Strength Method (DSM) strength curve intended for calculating the resistance of non-compact and slender hot-rolled H profile cross-sections. [less ▲] Detailed reference viewed: 41 (11 ULg)Finite element model reduction for the determination of accurate conductive links and application to MTG IRS BTA Jacques, Lionel ; Thibert, Tanguy ; Jamotton, Pierre et al Conference (2014, October 15) Detailed reference viewed: 37 (11 ULg)Finite Element Model Reduction of Thermal Systems with Conductive and Radiative Heat Transfers Jacques, Lionel ; Masset, Luc ; Kerschen, Gaëtan Scientific conference (2015, March 24) The Lumped parameter method (LPM) is the main method used for space structures thermal design. It is very versatile and allows easy integration of user-defined components but the computation of the ... [more ▼] The Lumped parameter method (LPM) is the main method used for space structures thermal design. It is very versatile and allows easy integration of user-defined components but the computation of the conductive links is error-prone and still too often computed by hand. Widely used in structural design, the finite element method (FEM) is however not yet often used for thermal analysis. One of the main reasons is that the radiative exchange factors, usually computed through Monte Carlo ray tracing, are extremely expensive to compute due to the large number of elements composing a FE model. A new global approach for FE model reduction of thermal systems is presented. The method is based on an automated FE mesh partitioning leading to super-faces and super-nodes. It is tailored for radiative exchange factors computation, taking into account selected quadric recognition and material constraints. The method also provides accurate conductive links computation and enables a direct mapping of the reduced temperatures back onto the detailed FE mesh (for e.g. thermo-elastic analyses). The application to two instruments developed at the Centre Spatial de Liège in Belgium will be presented, namely the Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter and the Back Telescope Assembly (BTA) onboard Meteosat Third Generation. [less ▲] Detailed reference viewed: 33 (4 ULg)Finite Element Model Updating Based On Holographic and Speckle Interferometry Measurements: Rapport VIA-25 ; Golinval, Jean-Claude Conference given outside the academic context (1999) Optical measurement techniques look very promising for finite element (F.E.) model updating or error localisation of plate-like structures in the field of structural dynamics. The purpose of this paper is ... [more ▼] Optical measurement techniques look very promising for finite element (F.E.) model updating or error localisation of plate-like structures in the field of structural dynamics. The purpose of this paper is to investigate a way to better exploit the high spatial resolution inherent to these techniques in order to correct FE mesh discretisation errors and/or model parameter errors. An important assumption in F.E. model error detection is first to consider the initial mesh as sufficiently fine to well represent the measured (displacement or stress) field. In the case of model updating, the adjustment of the model is performed by minimising the difference between the outputs of the model and the exact solution with respect to design parameters. In the case of FE mesh adaptation, the exact solution has to be estimated whereas in the case of model parameter errors, it is directly measured. The idea developed in this paper is to take advantage of the high spatial resolution offered by optical techniques to calculate successively two error estimators using only measurements. The experimental field is first used for the detection of singular regions corresponding to high gradients. This estimator indicates the regions where a mesh refinement is required. Thus a second estimator is calculated and used for parameter error detection. [less ▲] Detailed reference viewed: 30 (1 ULg)Finite Element Model Updating of Plate-like Structures Using Modal Holographic Measurement Field ; Golinval, Jean-Claude Conference given outside the academic context (2002) Optical measurement techniques are very promising for finite element (F.E.) model updating or error localisation of plate-like structures in the field of structural dynamics. The purpose of this work is ... [more ▼] Optical measurement techniques are very promising for finite element (F.E.) model updating or error localisation of plate-like structures in the field of structural dynamics. The purpose of this work is to investigate a way to better exploit the high spatial resolution inherent to these techniques in order to correct FE mesh discretisation errors and/or model parameter errors. An important assumption in F.E. model error detection is first to consider the initial mesh as sufficiently fine to well represent the measured (displacement or stress) field. In the case of model updating, the adjustment of the model is performed by minimising the difference between the outputs of the model and the exact solution with respect to design parameters. In the case of FE mesh adaptation, the exact solution has to be estimated whereas in the case of model parameter errors, the reference solution is assumed to be the measured one. The idea developed in this paper is to take advantage of the high spatial resolution offered by optical techniques to calculate successively two error estimators using only measurements. The experimental field is first used for the detection of singular regions corresponding to high gradients. This estimator indicates the regions where a mesh refinement is required. Thus a second estimator is calculated and used for parameter error detection. [less ▲] Detailed reference viewed: 26 (1 ULg)Finite Element Model Updating of the Garteur SM-AG19 Structure ; Golinval, Jean-Claude Conference given outside the academic context (2001) This paper reports the procedure followed by the "LTAS-Vibrations et Identification des Structures" research group to generate a low order nite element (F.E.) model of the GARTEUR SM-AG19 structure ... [more ▼] This paper reports the procedure followed by the "LTAS-Vibrations et Identification des Structures" research group to generate a low order nite element (F.E.) model of the GARTEUR SM-AG19 structure proposed as benchmark in the framework of the European COST Action F3 in structural dynamics. The model is made of beam elements, local inertia and rigid body elements. First, the correlation of the experimental data with the results of the F.E. model shows different levels of discrepancies. To perform local error detection, the size of the measured mode shape vectors is first expanded to the size of the F.E. eigenvectors. Model error localisation is based on the computation of residual strain energy due to errors in the constitutive equations. Updating parameters are then selected using eigenvalue sensitivity and local error analyses. The error localisation procedure is followed by the updating process in order to improve the accuracy of the FE models. The quality of the results is assessed in terms of accuracy of the response prediction to structural modifications. [less ▲] Detailed reference viewed: 134 (3 ULg)Finite element modeling of an electrostatic painting device Deliège, Geoffrey ; ; in IEEE Transactions on Magnetics (2003), 39(3), 1432-1435 Detailed reference viewed: 11 (3 ULg)Finite Element Modeling of Electro-Mechanical Coupling in Capacitive Micro-Systems Rochus, Véronique ; ; Golinval, Jean-Claude Conference given outside the academic context (2005) In this paper advanced multi-physics simulations of micro-electro-mechanical systems (MEMS) are used to investigate their dynamic behaviour. The strong coupled electro-mechanical Finite Element (FE ... [more ▼] In this paper advanced multi-physics simulations of micro-electro-mechanical systems (MEMS) are used to investigate their dynamic behaviour. The strong coupled electro-mechanical Finite Element (FE) formulation is used to model the electro-mechanical interactions and to perform modal and transient analysis taking into account large deformation e®ects. The application examples simulate two micro-resonators consisting in a clamped-clamped beam suspended over a substrate (the lower electrode). When a voltage is applied between the beam and the substrate, electrostatic forces appear which force the beam to bend. When the applied voltage is increased up to the pull-in limit, the electrostatic force becomes dominant and the plates stick together. The pull-in voltage is an essential design parameters in capacitive micro-systems. Here we also de¯ne a new design parameter describing the limit dynamic behaviour, namely the dynamic pull-in voltage. [less ▲] Detailed reference viewed: 52 (3 ULg)Finite element modeling of electrostatic MEMS including the impact of fringing field effects on forces Boutaayamou, Mohamed ; V Sabariego, Ruth ; Dular, Patrick in Sensor Letters (2008), 6(1), 115-120 The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking fringing fields into account is crucial for an accurate ... [more ▼] The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking fringing fields into account is crucial for an accurate computation of the electrostatic forces. In this work, the finite element method is applied for modeling electrostatic actuators. The electrostatic force distribution is obtained by locally applying the virtual work method. A micro-beam and a comb drive are considered as test cases. The impact of the fringing field effects on the accurate computation of electrostatic forces and capacitances is shown through 2D and 3D parametric studies. [less ▲] Detailed reference viewed: 136 (48 ULg)Finite element modeling of incremental forming of aluminium sheets ; ; et al in Advanced Materials Research (2005), 6/8 Incremental forming is an innovative and flexible sheet metal forming technology for small batch production and prototyping, which does not require any dedicated die or punch to form a complex shape. This ... [more ▼] Incremental forming is an innovative and flexible sheet metal forming technology for small batch production and prototyping, which does not require any dedicated die or punch to form a complex shape. This paper investigates the process of single point incremental forming of an aluminum cone with a 50-degree wall angle both experimentally and numerically. Finite element models are established to simulate the process. The output of the simulation is given in terms of final geometry, the thickness distribution of the product, the strain history and distribution during the deformation as well as the reaction forces. Comparison between the simulation results and the experimental data is made. [less ▲] Detailed reference viewed: 102 (4 ULg)Finite Element Modeling of the Cyclic Wetting Mechanism in the Active Part of Wheat Awns ; Ruffoni, Davide ; et al in BIOINTERPHASES (2012), 7(1-4), 42-9 Many plant tissues and organs are capable of moving due to changes in the humidity of the environment, such as the opening of the seed capsule of the ice plant and the opening of the pine cone. These are ... [more ▼] Many plant tissues and organs are capable of moving due to changes in the humidity of the environment, such as the opening of the seed capsule of the ice plant and the opening of the pine cone. These are fascinating examples for the materials engineer, as these tissues are non-living and move solely through the differential swelling of anisotropic tissues and in principle may serve as examples for the bio-inspired design of artificial actuators. In this paper, we model the microstructure of the wild wheat awn (Triticum turgidum ssp. dicoccoides) by finite elements, especially focusing on the specific microscopic features of the active part of the awn. Based on earlier experimental findings, cell walls are modeled as multilayered cylindrical tubes with alternating cellulose fiber orientation in successive layers. It is shown that swelling upon hydration of this system leads to the formation of gaps between the layers, which could act as valves, thus enabling the entry of water into the cell wall. This supports the hypothesis that this plywood-like arrangement of cellulose fibrils enhances the effect of ambient humidity by accelerated water or vapor diffusion along the gaps. The finite element model shows that a certain distribution of axially and tangentially oriented fibers is necessary to generate sufficient tensile stresses within the cell wall to open nanometer-sized gaps between cell wall layers. [less ▲] Detailed reference viewed: 19 (3 ULg)Finite element modeling of the thermoelastic damping in micro-electromechanical systems ; Golinval, Jean-Claude Conference (2005) Detailed reference viewed: 16 (1 ULg)Finite element modeling of thermo-mechanical behaviour of a steel strand in continuous casting Pascon, Frédéric ; Habraken, Anne ; et al in Habraken, Anne (Ed.) Proceedings of the 4th International Conference ESAFORM (2001) Surface and internal quality of continuous cast products depends very much upon the behaviour of the strand in the mould. Among the parameters likely to influence this behaviour, the mould taper takes a ... [more ▼] Surface and internal quality of continuous cast products depends very much upon the behaviour of the strand in the mould. Among the parameters likely to influence this behaviour, the mould taper takes a prominent part. In order to understand better the influence of this parameter, we have build up a thermo-mechanical finite element model. the model includes an elasto-visco-plastic law to describe the behaviour of steel from liquid to solid state, a thermo-mechanical element that takes into account thermal expansion and mechanical behaviour of the strand, a unilateral contact element, a mobile rigid boundary element to model the mould and its taper and an adapted loading element to model the ferrostatic pressure according to the liquid or solid state. [less ▲] Detailed reference viewed: 38 (6 ULg)Finite element modelling and optimization of flexible multibody systems Bruls, Olivier Scientific conference (2010, June) Detailed reference viewed: 32 (4 ULg)Finite element modelling of an electrostatic painting device Deliège, Geoffrey ; ; Conference (2002) Detailed reference viewed: 11 (1 ULg)Finite element modelling of composite structures under crushing load ; ; Boman, Romain et al in Composite Structures (2015), 131 This paper details the theory and implementation of a composite damage model, addressing damage within a ply (intralaminar) and delamination (interlaminar), developed for the simulation of the crushing of ... [more ▼] This paper details the theory and implementation of a composite damage model, addressing damage within a ply (intralaminar) and delamination (interlaminar), developed for the simulation of the crushing of laminated composite structures. It includes a more accurate determination of the characteristic length to achieve mesh objectivity in capturing intralaminar damage consisting of matrix cracking and fibre failure, a load-history dependent material response, an isotropic hardening nonlinear matrix response, as well as a more physically-based interactive matrix damage mechanism. The developed damage model requires a set of material parameters obtained from a combination of standard and non-standard material characterisation tests. The fidelity of the model mitigates the need to manipulate, or “calibrate”, the input data to achieve good agreement with experimental results. This intralaminar damage model was implemented as a VUMAT subroutine, and used in conjunction with an existing interlaminar damage model, in Abaqus/Explicit. This approach was validated through the simulation of the crushing of a cross-ply composite tube with a tulip-shaped trigger, loaded in uniaxial compression. Despite the complexity of the chosen geometry, excellent correlation was achieved with experimental results. [less ▲] Detailed reference viewed: 38 (6 ULg)Finite element modelling of electrostatic MEMS including the impact of fringing field effects on forces Boutaayamou, Mohamed ; ; V Sabariego, Ruth et al in Proceedings of the 7th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems (EuroSimE2006) (2006) The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking the fringing fields into account is crucial for an accurate ... [more ▼] The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking the fringing fields into account is crucial for an accurate computation of the electrostatic forces. In this work, the finite element method is applied for modeling electrostatic actuators. The electrostatic force distribution is obtained by locally applying the virtual work method. A micro-beam and a comb drive are considered as test cases. The impact of the fringing field effects on the accuracy of electrostatic forces is shown through 2D and 3D parametric studies. [less ▲] Detailed reference viewed: 82 (29 ULg) |
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