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See detailFinite Element Model Updating of Plate-like Structures Using Modal Holographic Measurement Field
Simon, Daniel; Golinval, Jean-Claude ULg

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 ▲]

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See detailFinite Element Model Updating of the Garteur SM-AG19 Structure
Thonon, Carole; Golinval, Jean-Claude ULg

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 ▲]

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See detailFinite element modeling of an electrostatic painting device
Deliège, Geoffrey ULg; Henrotte, François; Hameyer, Kay

in IEEE Transactions on Magnetics (2003), 39(3), 1432-1435

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See detailFinite Element Modeling of Electro-Mechanical Coupling in Capacitive Micro-Systems
Rochus, Véronique ULg; Rixen, Daniel; Golinval, Jean-Claude ULg

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 ▲]

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See detailFinite element modeling of electrostatic MEMS including the impact of fringing field effects on forces
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

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 ▲]

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See detailFinite element modeling of incremental forming of aluminium sheets
He, S.; Van Bael, A.; Van Houtte, P. 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 ▲]

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See detailFinite Element Modeling of the Cyclic Wetting Mechanism in the Active Part of Wheat Awns
Zickler, Gerald A.; Ruffoni, Davide ULg; Dunlop, John W. C. 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 ▲]

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See detailFinite element modeling of thermo-mechanical behaviour of a steel strand in continuous casting
Pascon, Frédéric ULg; Habraken, Anne ULg; Bourdouxhe, M. 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 ▲]

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See detailFinite element modelling and optimization of flexible multibody systems
Bruls, Olivier ULg

Scientific conference (2010, June)

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See detailFinite element modelling of an electrostatic painting device
Deliège, Geoffrey ULg; Henrotte, François; Hameyer, Kay

Conference (2002)

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See detailFinite element modelling of composite structures under crushing load
Chiu, Louis N.S.; Falzon, Brian G.; Boman, Romain ULg 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 ▲]

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See detailFinite element modelling of electrostatic MEMS including the impact of fringing field effects on forces
Boutaayamou, Mohamed ULg; Nair, Harish; V Sabariego, Ruth ULg 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 ▲]

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See detailFinite element modelling of ion convection by electrostatic forces
Deliège, Geoffrey ULg; Henrotte, François; Deprez, Wim et al

in IET Science, Measurement & Technology (2004), 151(6), 398-402

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See detailFinite element modelling of jointed rocks. Application to tunelling
Charlier, Robert ULg; El Kiri, Mohamed

in Int. Symp. on Assesment and preventin of failure phenomena in rocks engineering, ISMR (1993)

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See detailFinite element modelling of rock drilling.
Charlier, Robert ULg; Pierry, Joelle

in Int. Symp. on Assesment and prevention of failure phenomena in rocks engineering, ISMR (1993)

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See detailFinite element Modelling of Shear Band Localisation and Application to Rock Cutting by a PDC Tool
Pierry, J.; Charlier, Robert ULg

in Proc. EUROCK'94 (1994, August)

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See detailFinite element modelling of stacked thin regions with non-zero global currents
Dular, Patrick ULg; Gyselinck, Johan; Zeidan, Tarek et al

in Compel-the International Journal for Computation and Mathematics in Electrical and Electronic Engineering (2004), 23(3), 707-714

Develops a method to take the eddy currents in stacked thin regions, in particular lamination stacks, into account with the finite element method using the 3D magnetic vector potential magnetodynamic ... [more ▼]

Develops a method to take the eddy currents in stacked thin regions, in particular lamination stacks, into account with the finite element method using the 3D magnetic vector potential magnetodynamic formulation. It consists in converting the stacked laminations into continuums with which terms are associated for considering the eddy current loops produced by both parallel and perpendicular fluxes. Non-zero global currents can be considered in the laminations, in particular for studying the effect of imperfect insulation between their ends. The method is based on an analytical expression of eddy currents and is adapted to a wide frequency range. [less ▲]

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See detailFinite Element Modelling of Strong Electro-Mechanical Coupling in MEMS
Rochus, Véronique ULg

Doctoral thesis (2006)

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See detailFinite element modelling of the competition between shear bands in the early stage of thrusting : Strain localisation and constitutive law influence
Barnichon, Jean-Dominique; Charlier, Robert ULg

in Special Publication - Geological Society of London (1996), 99

Detailed reference viewed: 72 (6 ULg)