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See detailFinite element analysis of strongly nonlinear phenomena in deployable flexible systems
Bruls, Olivier ULg; Hoffait, Sébastien ULg; Cugnon, Frederic et al

in 1st ESA Multibody Dynamics Workshop on Multibody Dynamics for Space Applications, Noordwijk, 2010 (2010)

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See detailA finite element analysis of the bending and the bendability of metallic sheets
Ben Bettaieb, Mohamed ULg; Lemoine, Xavier; Bouaziz, O. et al

in International Journal of Material Forming (2011), 4(3), 283-297

The main objective of this paper is to study the bendability of metallic sheets by using the finite element method. In this aim, two variants of an advanced Gurson-Tvergaard-Needleman model [1, 2] are ... [more ▼]

The main objective of this paper is to study the bendability of metallic sheets by using the finite element method. In this aim, two variants of an advanced Gurson-Tvergaard-Needleman model [1, 2] are implemented in the home made FE code LAGAMINE [3, 4] and coupled with the Thomason model to predict the coalescence of voids. This advanced model is an extension of the original one to take into account of the plastic anisotropy and the mixed (isotropic + kinematic) hardening of the matrix. The difference between the two variants is related to the modeling of the damage evolution. As the advanced model is used to study the bending process, its yield function is slightly modified in order to take into account the loadings with negative triaxiality ratios. These present implementations are used to simulate the pure bending process and to predict the bendability of dual phase (DP) steel. The combined effect of an initial geometrical imperfection and damage evolution on the bendability is also studied. [less ▲]

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See detailFinite Element Analysis of the Electro-Mechanical Coupling in MEMS
Rochus, Véronique ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

Conference given outside the academic context (2002)

This paper concerns the modelling of the strong electro-mechanical coupling appearing in micro-electro-mechanical systems (MEMS). These systems are very small devices (typical size of a few microns), in ... [more ▼]

This paper concerns the modelling of the strong electro-mechanical coupling appearing in micro-electro-mechanical systems (MEMS). These systems are very small devices (typical size of a few microns), in which electric phenomena as well as mechanical and dynamical phenomena exist. The coupling between the electric and mechanical fields induce non-linear terms in the dynamic equilibrium equations of these microscopic structures so that instability may occur. In this paper, the finite element method (FEM) is used to perform modal analysis around non-linear equilibrium positions, taking into account large displacements. [less ▲]

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See detailFinite element analysis of the free surface effects on the mechanical behavior of thin nickel polycrystals
Keller, Clément ULg; Hug, eric; Habraken, Anne ULg et al

in International Journal of Plasticity (2012), 29

The miniaturization of metallic samples has been proved to deeply affect their mechanical properties leading to a softening or a hardening effect depending on the order of the dimension reduction. The ... [more ▼]

The miniaturization of metallic samples has been proved to deeply affect their mechanical properties leading to a softening or a hardening effect depending on the order of the dimension reduction. The objective of this work is to provide new numerical results which explain the softening mechanisms on the mechanical behavior for nickel polycrystals which have been experimentally characterized by the authors in a previous published paper (Keller et al., 2011). Based on a strain gradient crystalline plasticity model identified for nickel, simulations of tensile tests were performed for samples with different thicknesses and grain sizes. The simulations correctly reproduce the softening effect linked to a decrease in the thickness and in the number of grains across the thickness. The analysis of the plasticity mechanisms shows that the softening is due to surface effects which are discussed in terms of grain orientations, dislocation mean free path and long-range back-stress. The model also predicts a hardening mechanism for further dimension reduction if the samples have only grain boundaries perpendicular to the tensile direction. In this case, the modification of the mechanical behavior is due to strain gradients formation. [less ▲]

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See detailFinite element analysis on implicitly defined domains: An accurate representation based on arbitrary parametric surfaces
Moumnassi, Mohammed; Belouettar, Salim; Béchet, Eric ULg et al

in Computer Methods in Applied Mechanics & Engineering (2011), 200(5-8), 774-796

In this paper, we present some novel results and ideas for robust and accurate implicit representation of geometric surfaces in finite element analysis. The novel contributions of this paper are threefold ... [more ▼]

In this paper, we present some novel results and ideas for robust and accurate implicit representation of geometric surfaces in finite element analysis. The novel contributions of this paper are threefold: (1) describe and validate a method to represent arbitrary parametric surfaces implicitly; (2) represent arbitrary solids implicitly, including sharp features using level sets and boolean operations; (3) impose arbitrary Dirichlet and Neumann boundary conditions on the resulting implicitly defined boundaries. The methods proposed do not require local refinement of the finite element mesh in regions of high curvature, ensure the independence of the domain’s volume on the mesh, do not rely on boundary regularization, and are well suited to methods based on fixed grids such as the extended finite element method (XFEM). Numerical examples are presented to demonstrate the robustness and effectiveness of the proposed approach and show that it is possible to achieve optimal convergence rates using a fully implicit representation of object boundaries. This approach is one step in the desired direction of tying numerical simulations to computer aided design (CAD), similarly to the isogeometric analysis paradigm. [less ▲]

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See detailFinite element based models for the analysis of bolted beam-to-column steel connections
Bursi, O.; Jaspart, Jean-Pierre ULg

in Proceedings of the IABSE Colloquium on Semi-Rigid Structural Connections (1996)

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See detailA finite element code for subsidence problems: LAGAMINE
Charlier, Robert ULg; Radu, Jean-Pol ULg; Li, Q. F.

in Bulletin of Engineering Geology & the Environment (1993), 47(1 / avril), 5-11

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See detailFinite Element Comparative Study of Ship Structural Details
Rigo, Philippe ULg; Membres ISSC 97, Committee II. 1 (Iwahashi et al.)

in Marine Structures (1998)

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See detailFinite element computation of electromechanical micro-switches and micro-pump actuators
Lejeune, Jean-Michel; Rochus, Véronique ULg; Golinval, Jean-Claude ULg

Conference given outside the academic context (2004)

a new methodology to model the electromechanical behavior of microscale system components is presented. The original approach proposed in this paper is based on a unified FE formulation of the strong ... [more ▼]

a new methodology to model the electromechanical behavior of microscale system components is presented. The original approach proposed in this paper is based on a unified FE formulation of the strong electromechanical interaction problem, in which both the electric and the mechanical fields are considered simultaneously. To this aim, finite elements based on the Mindlin shell theory are implemented. In order to illustrate the proposed methodology, numerical results are presented on the modelling and simulation of microscale electromechanical switches and microscale pump actuators. [less ▲]

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See detailFinite element computation of localisation using strain field refinement
Charlier, Robert ULg; Wang, X. C.

in 3rd Int. Conf. on Computational Plasticity, COMPLAS III (1992, April)

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See detailFinite Element Computation of Nonlinear Normal Modes
Renson, Ludovic ULg; Deliège, Geoffrey ULg; Noels, Ludovic ULg et al

in Fifth International Conference on Advanced COmputational Methods in ENgineering (2011)

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See detailFinite element computation of nonlinear normal modes of nonconservative systems
Renson, Ludovic ULg; Deliège, Geoffrey ULg; Kerschen, Gaëtan ULg

in Proceedings of the ISMA 2012 conference (2012, September)

Modal analysis, i.e., the computation of vibration modes of linear systems, is really quite sophisticated and advanced. Even though modal analysis served, and is still serving, the structural dynamics ... [more ▼]

Modal analysis, i.e., the computation of vibration modes of linear systems, is really quite sophisticated and advanced. Even though modal analysis served, and is still serving, the structural dynamics community for applications ranging from bridges to satellites, it is commonly accepted that nonlinearity is a frequent occurrence in engineering structures. Because modal analysis fails in the presence of nonlinear dynamical phenomena, the development of a practical nonlinear analog of modal analysis is the objective of this research. Progress in this direction has been made recently with the development of numerical techniques (harmonic balance, continuation of periodic solutions) for the computation of nonlinear normal modes (NNMs). Because these methods consider the conservative system, this study targets the computation of NNMs for nonconservative systems, i.e. defined as invariant manifolds in phase space. Specifically, a new finite element technique is proposed to solve the set of partial differential equations governing the manifold geometry. The algorithm is demonstrated using different two-degree-of-freedom systems. [less ▲]

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See detailFinite Element Computational Homogenization for Heterogeneous Materials in Magnetodynamics
Niyonzima, Innocent ULg; Vazquez Sabariego, Ruth ULg; Dular, Patrick ULg et al

in Proceedings of the Fifth International Conference on Advanced COmputational Methods in ENgineering (ACOMEN 2011) (2011, November)

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See detailFinite Element Computational Homogenization of Nonlinear Multiscale Materials in Magnetostatics
Niyonzima, Innocent ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg et al

in 18th Conference on the Computation of Electromagnetic Fields (COMPUMAG2011) (2011)

This paper deals with the modelling of nonlinear multiscale materials in magnetostatics by means of a finite element computational homogenization method. The method couples a macroscale problem with many ... [more ▼]

This paper deals with the modelling of nonlinear multiscale materials in magnetostatics by means of a finite element computational homogenization method. The method couples a macroscale problem with many microscale problems. During the upscaling step, the homogenized magnetic permeability and its derivative with respect to the magnetic field are calculated from the microscale solution and transferred to the macroscale. The downscaling step consists in imposing proper boundary conditions for the microscale problems from the macroscale solution. Results are validated by comparison with those obtained with classical finite element brute force approach. [less ▲]

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See detailFinite Element Computational Homogenization of Nonlinear Multiscale Materials in Magnetostatics
Niyonzima, Innocent ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg et al

in IEEE Transactions on Magnetics (2012), 48(2), 587-590

The increasing use of composite materials in the technological industry (automotive, aerospace, ...) requires the development of effective models that account for the complexity of the microstructure of ... [more ▼]

The increasing use of composite materials in the technological industry (automotive, aerospace, ...) requires the development of effective models that account for the complexity of the microstructure of these materials and the nonlinear behaviour they can exhibit. In this paper we develop a multiscale computational homogenization method for modelling nonlinear multiscale materials in magnetostatics based on the finite element method. The method solves the macroscale problem by getting data from certain microscale problems around some points of interest. The missing nonlinear constitutive law at the macroscale level is derived through an upscaling from the microscale solutions. The downscaling step consists in imposing a source term and determining proper boundary conditions for microscale problems from the macroscale solution. For a two-dimensional geometry, results are validated by comparison with those obtained with a classical brute force finite element approach and a classical homogenization technique. The method provides a good overall macroscale response and more accurate local data around points of interest. [less ▲]

Detailed reference viewed: 110 (31 ULg)
See detailFinite Element Discretizations to Evaluate Electrostatic Forces Around Corners
Hannot, Stephan; Rixen, Daniel; Rochus, Véronique ULg

(2007)

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See detailA finite element for thermo-mechanical problems.
Bourdouxhe, Michel; Charlier, Robert ULg; Cescotto, Serge ULg

in Proceedings Numiform Conference Göteborg (1986, August)

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See detailFinite element formulation and couplings
Habraken, Anne ULg; Collin, Frédéric ULg

Conference (2013)

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See detailA finite element formulation for spectral problems in optical fibers
Guenneau, S.; Nicolet, A.; Zolla, F. et al

in COMPEL (2001), 20(1), 120--131

Detailed reference viewed: 7 (2 ULg)