References of "Golinval, Jean-Claude"
     in
Bookmark and Share    
Full Text
See detailStiction failure in microswitches due to elasto-plastic adhesive contact and cyclic loading
Wu, Ling ULg; Golinval, Jean-Claude ULg; Noels, Ludovic ULg

Scientific conference (2012, November 24)

Undesirable stiction, which results from contact between surfaces, is a major failure mode in micro-switches. This is especially true when contact happens between surfaces where elastoplastic asperities ... [more ▼]

Undesirable stiction, which results from contact between surfaces, is a major failure mode in micro-switches. This is especially true when contact happens between surfaces where elastoplastic asperities deform permanently until the surfaces reach plastic accommodation. Indeed before or at accommodation, the adhesive forces can become so important that the two surfaces remain permanently glued, limiting the life-time of the MEMS. To predict the behavior a micro adhesive-contact model is developed, which account for the surfaces topography evolutions during elasto-plastic contacts. This model can be used at a higher scale to study the MEMS behavior, and thus its life-time. The MEMS devices studied here are assumed to work in a dry environment. In these operating conditions only the Van der Waals forces have to be considered for adhesion. For illustration purpose, an electrostatic-structural analysis is performed on a micro-switch. To determine the degree of plasticity involved, the impact energy of the movable electrode at pull-in is estimated. Thus the maximal adhesive force is predicted using the developed model.Within this formalism, the cyclic loading and accommodation effects can be taken into account, as represented on the picture, which shows the non-dimensional force vs. separation distance of two rough surfaces after different cycle numbers. [less ▲]

Detailed reference viewed: 14 (0 ULg)
Full Text
Peer Reviewed
See detailQualification d’un appareil d'éclairage décoratif soumis aux vibrations induites par un pont ferroviaire
Marin, Frédéric; Simon, Daniel; Golinval, Jean-Claude ULg

in Serra, Roger (Ed.) 3ième Colloque "Analyse Vibratoire Expérimentale" (2012, November)

Au même titre que la plupart des pièces mécaniques soumises aux vibrations, les appareils d'éclairage installés en extérieur sont amenés à satisfaire, en fonction de leurs conditions d’utilisation, aux ... [more ▼]

Au même titre que la plupart des pièces mécaniques soumises aux vibrations, les appareils d'éclairage installés en extérieur sont amenés à satisfaire, en fonction de leurs conditions d’utilisation, aux exigences de procédures d'essais appliquées sur table vibrante. Celles-ci ont pour but de garantir l'intégrité structurelle du luminaire lorsque, une fois sur site, il est soumis aux effets du vent. Dans le cas des appareils d'éclairage décoratifs installés sur un pont de chemin de fer de structure métallique, le vent n'étant plus la source principale de vibrations en comparaison du trafic ferroviaire, on est dès lors confronté à une absence de toute indication appropriée décrivant l'essai à mener. Par conséquent, l'objectif de cette étude est d'élaborer une spécification d'essai de durée réduite, appliquée en laboratoire sur table vibrante, et représentative de l'environnement vibratoire réel de l'appareil à certifier. Sur base des essais réalisés en laboratoire, des prescriptions de montage et d'installation sont également formulées afin de garantir des conditions d’utilisation et d’essai identiques. [less ▲]

Detailed reference viewed: 34 (4 ULg)
Full Text
Peer Reviewed
See detailDétection d'endommagement et résonances locales sur composite CFRP par vibrothermographie
Demy, Philippe ULg; Golinval, Jean-Claude ULg; Simon, Daniel

in Serra, Roger (Ed.) 3ième Colloque "Analyse Vibratoire Expérimentale" (2012, November)

La vibrothermographie est une technique de thermographie active capable de détecter des singularités de type délaminage ou décollement dans un matériau composite comme les laminés en fibres de carbone ... [more ▼]

La vibrothermographie est une technique de thermographie active capable de détecter des singularités de type délaminage ou décollement dans un matériau composite comme les laminés en fibres de carbone très utilisés actuellement en construction aéronautique (CFRP). Les causes physiques du mécanisme d'échauffement interne, suite à l'interaction avec les ondes élastiques, peuvent être la friction, l'hystérésis viscoélastique ou encore la déformation plastique. La méthode est efficace également sur des géométries complexes et requiert uniquement que les deux faces internes du délaminage soient libres de vibrer. Cette étude consiste à déterminer la relation entre l'échauffement observé et la fréquence d'une excitation sinusoïdale entre 8 et 27 kHz. Il apparaît clairement des pics d'échauffement pour certaines fréquences particulières. La comparaison avec les fréquences de résonance locale du défaut modélisé par éléments finis montre des similitudes avec l'apparition de certains de ces pics. Une étude expérimentale visant à exploiter la présence de ceux-ci montre l'intérêt d'un test vibrothermographique de type balayage rapide (chirp), dans l'optique de mettre sur pied un test court et fiable pour le contrôle non destructif de matériaux composites. [less ▲]

Detailed reference viewed: 135 (27 ULg)
Full Text
Peer Reviewed
See detailMéthodologie d’excitation de modes à diamètres nodaux d’un anneau statorique de turboréacteur
Nyssen, Florence ULg; Golinval, Jean-Claude ULg; Simon, Daniel et al

in Serra, Roger (Ed.) 3ième Colloque "Analyse Vibratoire Expérimentale" (2012, November)

Cette étude consiste à développer une approche expérimentale, permettant l’isolation de modes à diamètres nodaux spécifiques d’un étage statorique de compresseur basse pression, ayant pour objectif final ... [more ▼]

Cette étude consiste à développer une approche expérimentale, permettant l’isolation de modes à diamètres nodaux spécifiques d’un étage statorique de compresseur basse pression, ayant pour objectif final la calibration de jauges de déformation. Plus spécifiquement, une étude portant sur le nombre minimal de sources d’excitation (shakers) et sur leur répartition circonférentielle optimale a été menée, l’objectif suivi étant d’isoler des modes à diamètres cibles dans des conditions de laboratoire. La première partie de l’étude consiste en une approche théorique, basée sur les concepts d’appropriation modale en régime forcé. La combinaison optimale des positions des différents points d’excitation est choisie de façon à maximiser une fonction objectif, définie comme le rapport entre l’énergie injectée dans le mode cible et la valeur maximale des énergies injectées dans les modes présentant une fréquence naturelle proche du mode d’intérêt. Dans la deuxième partie de l’étude, des simulations numériques sur un modèle éléments finis de la structure ont été menées sur base des résultats théoriques obtenus. Enfin, la troisième partie a permis de valider expérimentalement les prédictions numériques via des analyses d’influence du nombre d’excitateurs et de leur position sur l’amplitude de la réponse fréquentielle. [less ▲]

Detailed reference viewed: 183 (45 ULg)
Full Text
Peer Reviewed
See detailIdentification modale de systèmes variant dans le temps à partir de réponses simulées sur un exemple d'éoliennes
Bertha, Mathieu ULg; Golinval, Jean-Claude ULg

Poster (2012, November)

Wind turbines are good examples of time-varying systems as their modal properties depend on their instantaneous configuration. To catch the variations of modal parameters in time-varying systems ... [more ▼]

Wind turbines are good examples of time-varying systems as their modal properties depend on their instantaneous configuration. To catch the variations of modal parameters in time-varying systems, classical identification methods have to be adapted to the non-stationary nature of the recorded signals. In this paper, it is proposed to study the dynamic behavior of an offshore five-megawatt wind turbine. First, a numerical model of the wind turbine is created to serve as reference. Then, the time-varying behavior of the system is evaluated by simulating a large number of possible configurations. To this purpose, time responses are generated from the numerical model submitted to different environmental conditions. The wind is considered as the main non-measured external excitation force on the structure and the responses are recorded at several locations to simulate a real measurement process. Special care is brought to the accessibility of the measurement locations and to the limited number of available sensors in practice. Using these simulated measurements, output-only identification methods are used to extract varying dynamic properties of the structure. The final objective of this work is to pave the way to online condition monitoring of wind turbines. [less ▲]

Detailed reference viewed: 88 (22 ULg)
See detailNonlinear Dynamic Analysis of Aerospace Structures
Kerschen, Gaëtan ULg; Noël, Jean-Philippe ULg; Renson, Ludovic ULg et al

Conference (2012, October)

Current practice in industry is to rely on linear finite element simulations. However, nonlinearity is a frequent occurrence in engineering structures. It is at the origin of rich and complex dynamical ... [more ▼]

Current practice in industry is to rely on linear finite element simulations. However, nonlinearity is a frequent occurrence in engineering structures. It is at the origin of rich and complex dynamical phenomena that cannot be observed in linear structures. Solving both the direct and inverse problems in nonlinear structural dynamics therefore warrants the development of appropriate methodologies. The focus of the presentation will first be on the inverse problem. We will describe the different steps of the nonlinear system identification process and discuss the current capabilities of existing methods. The presentation will then address the direct problem during which the identified model is used for accurately predicting the structure’s dynamic characteristics. A rigorous nonlinear extension of modal analysis will be presented, and we will show that it represents a very useful framework for understanding nonlinear dynamical phenomena and supporting design decisions. Two real-life aerospace structures will be considered for illustrating the proposed developments. [less ▲]

Detailed reference viewed: 62 (11 ULg)
Full Text
See detailDamage detection and local resonances model in CFRP composite material by vibrothermography
Demy, Philippe ULg; Golinval, Jean-Claude ULg; Simon, Daniel

Scientific conference (2012, September)

Vibrothermography (VT) is an active non destructive technique able to detect singularities like delamination, even if the defect internal faces are in contact. Under sonic or ultrasonic mechanical ... [more ▼]

Vibrothermography (VT) is an active non destructive technique able to detect singularities like delamination, even if the defect internal faces are in contact. Under sonic or ultrasonic mechanical vibrations, a delamination may behave like a heat source principally due to friction between the rubbing faces and/or stress concentration in the area. The present article focuses on the understanding of the underlying phenomenon so-called "local resonances" and its correlation with the presence of temperature peaks observed at certain frequencies. For this purpose, a simplified finite element modal analysis of the delamination model is compared with the heating rate vs. frequency data's acquired by an infrared camera. Then, some conclusive results of sine sweep and chirp testing will be presented and discussed in regards to this theory. [less ▲]

Detailed reference viewed: 47 (12 ULg)
Full Text
See detailModal identification of time-varying systems using simulated responses on wind turbines
Bertha, Mathieu ULg; Mayorga Rios, Jorge Patricio ULg; Golinval, Jean-Claude ULg

in Sas, P; Moens, D; Jonckheere, S (Eds.) Proceedings of ISMA2012-USD2012 (2012, September)

Wind turbines are good examples of time-varying systems as their modal properties depend on their instantaneous configuration. To catch the variations of modal parameters in time-varying systems ... [more ▼]

Wind turbines are good examples of time-varying systems as their modal properties depend on their instantaneous configuration. To catch the variations of modal parameters in time-varying systems, classical identification methods have to be adapted to the non-stationary nature of the recorded signals. In this paper, it is proposed to study the dynamic behavior of an offshore five-megawatt wind turbine. First, a numerical model of the wind turbine is created to serve as reference. Then, the time-varying behavior of the system is evaluated by simulating a large number of possible configurations. To this purpose, time responses are generated from the numerical model submitted to different environmental conditions. The wind is considered as the main non-measured external excitation force on the structure and the responses are recorded at several locations to simulate a real measurement process. Special care is brought to the accessibility of the measurement locations and to the limited number of available sensors in practice. Using these simulated measurements, output-only identification methods are used to extract varying dynamic properties of the structure. The final objective of this work is to pave the way to online condition monitoring of wind turbines. [less ▲]

Detailed reference viewed: 47 (15 ULg)
Full Text
See detailÉtalonnage dynamique des capteurs piézoélectriques pour la mesure de haute pression balistique
Elkarous, Lamine ULg; Pirlot, Marc; Golinval, Jean-Claude ULg

in 4ème Conférence Internationale de métrologie - CAFMET2012 (2012, April 24)

Detailed reference viewed: 60 (12 ULg)
Full Text
Peer Reviewed
See detailDamage Detection on the Champangshiehl Bridge using Blind Source Separation
Nguyen, Viet Ha; Rutten, Christophe; Golinval, Jean-Claude ULg et al

in Strauss, Alfred; Frangopol, Dan M.; Bergmeister, Konrad (Eds.) Life-Cycle and Sustainability of Civil Infrastructure Systems (2012)

This paper addresses the problem of damage detection in civil engineering structures using characteristic subspaces obtained from principal component analysis (PCA) of output-only measurements. Damage ... [more ▼]

This paper addresses the problem of damage detection in civil engineering structures using characteristic subspaces obtained from principal component analysis (PCA) of output-only measurements. Damage detection is performed by comparing subspace features between a reference (healthy) state and a current (possibly damaged) state. The damage indicator used in this study is the angular coherence between sub-spaces. The considered damage detection procedure is illustrated on the Champangshiehl Bridge which is a two span concrete box girder bridge located in Luxembourg. Before its destruction, multiple damage levels were inten-tionally created by cutting a growing number of prestressed tendons. Vibration data were acquired by the University of Luxembourg for each damaged state at many locations on the bridge. As previous studies dem-onstrated the large importance of environmental factors on modal identification, special care was taken to evaluate this influence during the test campaign. [less ▲]

Detailed reference viewed: 58 (8 ULg)
Full Text
Peer Reviewed
See detailFault Diagnosis in Industrial Systems Based on Blind Source Separation Techniques Using One Single Vibration Sensor
Nguyen, Viet Ha; Rutten, Christophe; Golinval, Jean-Claude ULg

in Shock & Vibration (2012), 19(5), 795-801

In the field of structural health monitoring or machine condition monitoring, most vibration based methods reported in the literature require to measure responses at several locations on the structure. In ... [more ▼]

In the field of structural health monitoring or machine condition monitoring, most vibration based methods reported in the literature require to measure responses at several locations on the structure. In machine condition monitoring, the number of available vibration sensors is often small and it is not unusual that only one single sensor is used to monitor a machine. The aim of this paper is to propose an extension of fault detection techniques that may be used when a reduced set of sensors or even one single sensor is available. Fault detection techniques considered here are based on output-only methods coming from the Blind Source Separation (BSS) family, namely Principal Component Analysis (PCA) and Second Order Blind Identification (SOBI). The advantages of PCA or SOBI rely on their rapidity of use and their reliability. Based on these methods, subspace identification may be performed by using the concept of block Hankel matrices which make possible the use of only one single measurement signal. Thus, the problem of fault detection in mechanical systems can be solved by using subspaces built from active principal components or modal vectors. It consists in comparing subspace features between the reference (undamaged) state and a current state. The angular coherence between subspaces is a good indicator of a dynamic change in the system due to the occurrence of faults or damages. The robustness of the methods is illustrated on industrial examples. [less ▲]

Detailed reference viewed: 33 (3 ULg)
Full Text
Peer Reviewed
See detailNanomechanical and nanotribological characterization of microelectromechanical system
Pustan, Marius; Muller, Raluca; Golinval, Jean-Claude ULg

in Journal of Optoelectronics and Advanced Materials [= JOAM] (2012), 14(3-4), 401-412

Investigations of the mechanical and tribological properties of microelectromechanical system (MEMS) components on nanoscale can provide insights into failure mechanism of material. The main goal of this ... [more ▼]

Investigations of the mechanical and tribological properties of microelectromechanical system (MEMS) components on nanoscale can provide insights into failure mechanism of material. The main goal of this paper is focused on the mechanical and tribological characterizations of MEMS mechanical components in order to improve their reliability design. The mechanical properties of interests are stiffness, modulus of elasticity, stress, strain. Dynamical investigations are performed to analyze the resonant frequency response, velocity and amplitude of oscillations of electrostatically actuated microcomponents and to estimate the quality factor. Finite element analysis is used to validate the experimental results of mechanical properties and to simulate the dynamical behaviour of investigated microcomponents. Tribological investigations are developed to estimate the stiction and friction. Testing and the individual characterization of MEMS materials and structures, performed using advanced equipments such as atomic force microscope and optical vibrometer analyzer are presented. [less ▲]

Detailed reference viewed: 122 (1 ULg)
Full Text
See detailStiction failure in microswitches due to elasto-plastic adhesive contact
Wu, Ling ULg; Golinval, Jean-Claude ULg; Noels, Ludovic ULg

in Proceedings of the XII SEM International Conference & Exposition on Experimental and Applied Mechanics (2012)

Undesirable stiction, which results from contact between surfaces, is a major failure mode in micro-switches. Indeed the adhesive forces can become so important that the two surfaces remain permanently ... [more ▼]

Undesirable stiction, which results from contact between surfaces, is a major failure mode in micro-switches. Indeed the adhesive forces can become so important that the two surfaces remain permanently glued, limiting the life-time of the MEMS. This is especially true when contact happens between surfaces where elasto-plastic asperities deform permanently until the surfaces reach plastic accommodation, increasing the surface forces. To predict this behavior, a micro adhesive-contact model is developed, which accounts for the surfaces topography evolutions during elasto-plastic contacts. This model can be used at a higher scale to study the MEMS behavior, and thus its life-time. The MEMS devices studied here are assumed to work in a dry environment. In these operating conditions only the Van der Waals forces have to be considered for adhesion. For illustration purpose, an electrostatic-structural analysis is performed on a micro-switch. To determine the degree of plasticity involved, the impact energy of the movable electrode at pull-in is estimated. Thus the maximal adhesive force is predicted using the developed model. [less ▲]

Detailed reference viewed: 44 (7 ULg)
Full Text
Peer Reviewed
See detailMechanical and tribological characterization of a thermally actuated MEMS cantilever
Pustan, Marius; Rochus, Véronique; Golinval, Jean-Claude ULg

in Microsystem Technologies (2012)

The temperature effect on the mechanical and tribological behaviors of a microelectromechanical systems cantilever is experimentally investigated using an atomic force microscope. A nonlinear variation of ... [more ▼]

The temperature effect on the mechanical and tribological behaviors of a microelectromechanical systems cantilever is experimentally investigated using an atomic force microscope. A nonlinear variation of the bending stiffness of microcantilevers as a function of temperature is determined. The variation of the adhesion force between the tip of atomic force microscope (AFM) probe (Si3N4) and the microcantilever fabricated in gold is monitored at different temperatures. Using the lateral mode operation of atomic force microscope, the influence of temperature on friction coefficient between the tip of AFM probe and microcantilever is presented. Finite element analysis is used to estimate the thermal field distribution in microcantilever and the axial expansion. [less ▲]

Detailed reference viewed: 14 (0 ULg)
Full Text
Peer Reviewed
See detailDétection d'endommagement de structures en matériaux composites CFRP par vibrothermographie
Demy, Philippe ULg; Golinval, Jean-Claude ULg; Simon, Daniel

in Desse, Jean-Michel; Picart, Pascal; Tankam, Patrice (Eds.) Actes du 12ème colloque international francophone sur les méthodes et techniques optiques pour l'industrie (2011, November 21)

La vibrothermographie (VT) est une technique de thermographie active basée sur le fait que, sous l’action de vibrations mécaniques induites dans une structure, les défauts peuvent se comporter comme des ... [more ▼]

La vibrothermographie (VT) est une technique de thermographie active basée sur le fait que, sous l’action de vibrations mécaniques induites dans une structure, les défauts peuvent se comporter comme des sources de chaleur internes suite à leur interaction avec les ondes élastiques. Ces vibrations peuvent être générées notamment par un excitateur piézoélectrique. La dissipation d’énergie au niveau des singularités liées à la présence de défauts est détectable par une caméra thermique infrarouge. Parmi les mécanismes physiques sous-jacents du phénomène, on relève essentiellement les pertes par friction et hystérésis plastique [1,2]. Des recherches plus approfondies prenant en compte divers facteurs comme les non linéarités de couplage font actuellement l'objet de divers travaux afin de mieux comprendre le phénomène et d'améliorer la fiabilité de la méthode [3,4]. L'objectif de cet article est l'évaluation des potentialités de la vibrothermographie, menée sur différents échantillons en matériaux composites CFRP (Carbon Fiber Reinforced Plastic) utilisés en aéronautique. La technique est prometteuse dans le domaine des essais non destructifs (CND), et apporte une complémentarité aux méthodes conventionnelles utilisables sur ce type de matériaux, comme la radiographie X, les ultrasons ou encore l'interférométrie de speckle [5]. En effet, avec la VT, la détection de défauts est indépendante de leurs orientations dans le spécimen. De plus, des défauts internes relativement profonds peuvent être détectés, y compris sur des échantillons de géométries complexes. C'est pourquoi la VT est particulièrement utile pour la détection de fissures et de délaminations dans les CFRP [6]. Une comparaison expérimentale avec des résultats obtenus par thermographie pulsée optique (stimulation thermique par lampes chauffantes) est également présentée. [less ▲]

Detailed reference viewed: 66 (6 ULg)
Full Text
See detailInfluence of the elasto-plastic adhesive contact on Micro-Switches
Wu, Ling ULg; Golinval, Jean-Claude ULg; Noels, Ludovic ULg

in Hogge, Michel; Van Keer, Roger; Dick, Erik (Eds.) et al Proceedings of the 5th International Conference on Advanded COmputational Methods in Engineering (ACOMEN2011) (2011, November)

Undesirable stiction, which results from contact between surfaces, is a major failure mode in micro,electro-mechanical systems (MEMS). In previous works, a statistical rough surfaces interaction,model ... [more ▼]

Undesirable stiction, which results from contact between surfaces, is a major failure mode in micro,electro-mechanical systems (MEMS). In previous works, a statistical rough surfaces interaction,model, based on Maugis and Kim formulations has been presented to estimate the adhesive forces in MEMS switches. In this model, only elastic adhesive contact has been considered. However, during the impact between rough surfaces, at pull-in process for example, plastic deformations of the rough surfaces cannot be always neglected especially for the MEMS with metallic contact surfaces. In the present work, a new micro-model predicting the adhesive-contact force on a single elasticplastic asperity interacting with a rigid plane is presented. This model will be used later on for the interaction between two elastic-plastic rough surfaces. The MEMS devices studied here are assumed to work in a dry environment. In these operating conditions only the Van der Waals forces have to be considered for adhesion. [less ▲]

Detailed reference viewed: 33 (5 ULg)
Full Text
Peer Reviewed
See detailA Micro-Macroapproach to Predict Stiction due to Surface Contact in Microelectromechanical Systems
Wu, Ling ULg; Noels, Ludovic ULg; Rochus, Véronique et al

in IEEE/ASME Journal of Microelectromechanical Systems (2011), 20(4), 976-990

Stiction, which results from contact between surfaces, is a major failure mode in micro electro-mechanical systems (MEMS). Indeed microscopic structures tend to adhere to each other when their surfaces ... [more ▼]

Stiction, which results from contact between surfaces, is a major failure mode in micro electro-mechanical systems (MEMS). Indeed microscopic structures tend to adhere to each other when their surfaces enter into contact and when the restoring forces are unable to overcome the interfacial forces. Since incidental contacts cannot be completely excluded and since contacts between moving parts can be part of the normal operation of some types of MEMS, stiction prediction is an important consideration when designing micro and nano-devices. In this paper a micro-macro multi-scale approach is developed in order to predict possible stiction. At the lower scale, the unloading adhesive contact-distance curves of two interacting rough surfaces are established based on a previously presented model [L. Wu et al., J. Appl. Phys. 106, 113502, 2009]. In this model, dry conditions are assumed and only the van der Waals forces as adhesion source are accounted for. The resulting unloading adhesive contact-distance curves are dependant on the material and on surface properties, such as, elastic modulus, surface energy and on the rough surfaces topography parameters; the standard deviation of asperity heights and the asperities density. At the higher scale, a finite element analysis is considered to determine the residual cantilever beam configuration due to the adhesive forces once contact happened. Toward this end, the adhesive contact-distance curve computed previously is integrated on the surface of the finite elements as a contact law. Effects of design parameters can then be studied for given material and surface properties. [less ▲]

Detailed reference viewed: 191 (93 ULg)
Full Text
Peer Reviewed
See detailModeling and finite element analysis of mechanical behavior of flexible MEMS components
Pustan, Marius ULg; Paquay, Stéphane; Rochus, Véronique et al

in Microsystem Technologies (2011), 17(4), 553-562

This paper describes the studies of the mechanical characteristics of flexible MEMS components including theoretical approaches, finite element analysis and experimental investigations. Modeling and ... [more ▼]

This paper describes the studies of the mechanical characteristics of flexible MEMS components including theoretical approaches, finite element analysis and experimental investigations. Modeling and finite element analyses together with theoretical and experimental investigations are performed to estimate the elastic behavior of MEMS components as microcantilevers, microbridges and micromembranes. Finite element analysis of microcomponents deflections under different loading and the stress distribution in beams are determined and compared with the experimental measurements performed using an atomic force microscope. The modeling of a micromembrane supported by four hinges that enable out-of-plane motion is presented. Finite element analysis and experimental investigations are performed to visualize the deflection of the mobile part of the micromembrane under an applied force and the stress distribution in hinges. In additional, this paper provides analytical relations to compute the stiffness and the stress of the investigated flexible MEMS components. [less ▲]

Detailed reference viewed: 24 (3 ULg)
Full Text
Peer Reviewed
See detailEffects of the electrode positions on the dynamical behaviour of electrostatically actuated MEMS resonators
Pustan, Marius ULg; Paquay, Stéphane; Rochus, Véronique et al

(2011, April 18)

The influence of the lower electrode positions on the dynamic response of polysilicon MEMS resonators is studied and presented in this paper. The change in the frequency response of investigated MEMS ... [more ▼]

The influence of the lower electrode positions on the dynamic response of polysilicon MEMS resonators is studied and presented in this paper. The change in the frequency response of investigated MEMS resonators as function of the lower electrode positions is measured using a vibrometer analyzer. The decrease in the amplitude and velocity of oscillations if the lower electrode is moved from the beam free-end toward to the beam anchor is experimental monitored. The measurements are performed in ambient conditions in order to characterize the forced-response Q-factor of samples. A decrease of the Q- factor if the lower electrode is moved toward to the beam anchor is experimental determined. Different responses of MEMS resonators may be obtained if the position of the lower electrode is modified. Indeed the resonator stiffness, velocity and amplitude of oscillations are changed. [less ▲]

Detailed reference viewed: 30 (3 ULg)
Full Text
See detailInvestigation on gas pressure measurement inside small caliber weapons with piezoelectric transducers
Elkarous, Lamine ULg; Pirlot, Marc; Golinval, Jean-Claude ULg et al

in Measurement Science Conference 2012 (2011, March 20)

Detailed reference viewed: 18 (3 ULg)