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See detailMechanical and durability properties of concrete using contaminated recycled aggregates
Debieb, Farid; Kenaï, Saïd; Courard, Luc ULg et al

in Cement & Concrete Composites (2010), 32(6), 421-426

The degradation of concrete structures due to chlorides and sulphates penetration is of obvious importance in civil engineering as having major impact on structural durability. In this paper, the results ... [more ▼]

The degradation of concrete structures due to chlorides and sulphates penetration is of obvious importance in civil engineering as having major impact on structural durability. In this paper, the results of an investigation on the effect of contaminated crushed concrete aggregates on mechanical properties and durability of recycled concrete are presented. Natural aggregates concrete (NC) slabs were cured in water, sea water, chloride solutions or sulphate solutions and then crushed to obtain virgin and contaminated (polluted) recycled aggregates. The properties of natural (NA) and recycled aggregates (RA) and the mechanical properties and durability performances of a new concrete made from 100% of RA are analysed. The results show that contaminated RA are much sensitive to chlorides than sulphates and are rapidly leached when soaked into water. Significant differences were observed between the properties of original and new concrete and the results clearly show the necessity of taking these contaminations into account. [less ▲]

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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 ▲]

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See detailMechanical approach for the characterization of loess deposits from the CBR’s Romont quarry (Eben-Emael, Belgium) and correlations with loess stratigraphy
Delvoie, Simon ULg; Boulvain, Frédéric ULg; Cerfontaine, Benjamin ULg et al

Conference (2015, June 01)

Aeolian silts (loess) are near surface deposits covering about 10% of the continent surfaces . Therefore a good knowledge of their mechanical behavior is an issue for designing subsurface engineering ... [more ▼]

Aeolian silts (loess) are near surface deposits covering about 10% of the continent surfaces . Therefore a good knowledge of their mechanical behavior is an issue for designing subsurface engineering structures. Usually this material is considered as homogeneous for an engineering point of view. Aeolian silt deposits are continuously well developed in Hesbaye Region (Belgium) reaching locally 20m thick (see document in attachment). They are mainly related to the last interglacial (Eemian) and glacial (Weichselian) periods . Nevertheless the pedostratigraphical, chronostratigraphical and paleoclimatic approaches have shown these silt deposits are usually composed of a series of paleosoils (i.e. Rocourt soil, Humiferous Complex of Remicourt, Harmignies Soil, Nagelbeek Tongued Horizon) interbedded with stratified or homogeneous aeolian silt layers. This study aims to characterize the variability of the in situ mechanical characteristics of the loess deposits from Hesbaye Region at the site scale and at the laboratory scale. Cone penetration tests (CPT), electrical resistivity tomographies (ERT) and drillings have been performed through a 10m thick loess layer in an investigation site located close to the CBR’s Romont quarry (Eben-Emael, Belgium) . Continuous undisturbed silt samples from drillings have been physically (granulometry, Atterberg limits, water content, organic matter content, carbonate content) and mechanically (oedometer test, triaxial test) characterized at the laboratory. Mechanical behavior and physical characteristics have underlined a series of layers with variable mechanical properties through depth. Some of these layers correlated with a detailed stratigraphy cross-section close to the investigation site could correspond to well-known paleosoils. [less ▲]

Detailed reference viewed: 93 (11 ULg)
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See detailMechanical based circular notch hinge design
Merken, Patrick; Smal, Olivier; Debongnie, Jean-François ULg et al

Report (2007)

At the microscale, classical bearings such as ball bearings, sliding bearings and other pivots may be difficult to manufacture. Among all possible solutions to replace them, the notch hinge seems to be ... [more ▼]

At the microscale, classical bearings such as ball bearings, sliding bearings and other pivots may be difficult to manufacture. Among all possible solutions to replace them, the notch hinge seems to be very attractive through its many advantages. The major limitation is on the rotation angle. This paper presents a new simplified analytical model for the prediction of the maximum angular displacement and the angular stiffness of a notch hinge. To validate our model, an experimental set-up has been developed. Finally, the results are compared to other theories. [less ▲]

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See detailMechanical behavior of a ferritic stainless steel under simple and complex loading paths
Rossi, Barbara ULg; Jaspart, Jean-Pierre ULg

in International Conference on Structure and Architecture : ICSA2010, Guimaraes 21-23 July 2010 (2010)

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See detailMechanical behavior of ferritic grade 3Cr12 stainless steel-Part 1: Experimental investigations.
Rossi, Barbara ULg

in Thin-Walled Structures (2010), 48(7), 540-552

Ferritic stainless steels are corrosion resistant steels with a low and stable cost. Widely used in automotive applications, structural applications using ferritic stainless steels are only emerging ... [more ▼]

Ferritic stainless steels are corrosion resistant steels with a low and stable cost. Widely used in automotive applications, structural applications using ferritic stainless steels are only emerging mainly because ferritics are partially covered by structural standards due to a shortage of design data. Computer models are more and more used to support the developments of conventional design methods based on expensive full-scale tests or trial and errors methods. And for the modeling of metal forming processes as well as structural behavior of members, it is necessary to afford an accurate knowledge of the mechanical properties. In this paper, the experimental investigations made on the chromium based alloy 3Cr12 (1.4003) in order to characterize its mechanical behavior are presented. During the research, a classical uniaxial experimental equipment and a bi-axial experimental equipment designed by Flores (2005) in the Structures Laboratory of the University of Lige have been used. The collection of tests performed included tensile tests, cyclic shear tests, simple shear tests and successive simple shear and plane-strain tests. The yield locus and the hardening models are presented and identified in a companion paper by the same author. [less ▲]

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See detailMechanical behavior of ferritic grade 3Cr12 stainless steel-Part 2: Yield locus and hardening laws
Rossi, Barbara ULg

in Thin-Walled Structures (2010), 48(7), 553-560

In practice, the finite element method is quite successful in simulating the metal forming processes or the structural behavior of members carrying loads. The accuracy of such models largely depends on ... [more ▼]

In practice, the finite element method is quite successful in simulating the metal forming processes or the structural behavior of members carrying loads. The accuracy of such models largely depends on the mechanical laws used to describe the material behavior. Numerous authors have shown the effect of material anisotropy on deep drawing or the influence of non-linear hardening behavior on the resistance of structural members. Studies have also demonstrated how important the evaluation of the material parameters is during the theoretical calculation of the strength of stainless steel members for instance. Non-linear metallic materials emerge as an alternative to elastic perfectly plastic materials, be it for their stainless, ductility or strength properties. It is thus necessary to be able to accurately model their material behavior. In the present paper, prior to any computations, different laws are described: simple phenomenological law and micro–macro constitutive models based on crystal plasticity. Classical yield surface such as Hill one are combined with isotropic (Swift or Ramberg– Osgood) and kinematic (Armstrong–Frederick or Teodosiu–Hu) hardening models to define the material behavior. The material parameters included in each law are then carefully identified. For that purpose, the experimental equipment developed by Flores (2005) in the Structures Laboratory of the University of Liege was used to perform biaxial tests. Coupled with classical uniaxial tests, they provide the necessary data for the identification of the yield locus and the hardening models. [less ▲]

Detailed reference viewed: 106 (25 ULg)
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See detailMechanical behaviour model of an unsaturated sandy silt
Charlier, Robert ULg; Li, X. L.; Bolle, Albert ULg et al

in Proc. of the XIVth Int. Conf. on Soil Mechanics and Foundation Engineering (1997, September)

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See detailMechanical behaviour of chalk reservoir: Numerical modelling of water sensitivity and time dependence effects
Collin, Frédéric ULg; Cui, Yu Jun; Schroeder, Christian ULg et al

Conference (2003)

The paper proposes two numerical models ot the mechanical behaviour of chalk. First, an elasto-plastic constitutive law reproduces the different plastic mechanisms of the chalk and the influence of pore ... [more ▼]

The paper proposes two numerical models ot the mechanical behaviour of chalk. First, an elasto-plastic constitutive law reproduces the different plastic mechanisms of the chalk and the influence of pore fluids by introducing the concept of suction. Secondly, a model able to reproduce time dependence behaviour. Eventually, the paper gives a simulation of an academic reservoir during depletion and waterflooding phase. [less ▲]

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See detailMechanical behaviour of chalk reservoirs: numerical modelling of water sensitivity effects
Collin, Frédéric ULg; Cui, Yu Jun; Schroeder, Christian ULg et al

Conference (2003)

Chalk is the constituent material of numerous oil reservoirs in North Sea. The mechanical behaviour of a saturated chalk has been largely studied. However, different aspects of its behaviour are not yet ... [more ▼]

Chalk is the constituent material of numerous oil reservoirs in North Sea. The mechanical behaviour of a saturated chalk has been largely studied. However, different aspects of its behaviour are not yet well understood: material characteristics depend on the saturating fluids and chalk response is time-dependent. This paper proposes the PASACHALK numerical model: an elasto-plastic constitutive law is presented, which reproduces the different plastic mechanisms of the chalk (pore collapse and shear failure) and the influence of pore fluids. The water sensitivity of this soft rock is explained by the existence of suction effects in chalk. Finally, a simulation of a hypothetical reservoir is proposed to show the response of the elasto-plastic model during depletion phase and water injection phase. [less ▲]

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See detailMechanical behaviour of Lixhe chalk partly saturated by oil and water: experiment and modelling
Collin, Frédéric ULg; Cui, Yu Jun; Schroeder, Christian ULg et al

in International Journal for Numerical and Analytical Methods in Geomechanics (2002), 26(9), 897-924

Two or more different fluids generally saturate chalk in oil reservoir, and therefore its behaviour can be very complicated. In this paper, a constitutive law is proposed for modelling the mechanical ... [more ▼]

Two or more different fluids generally saturate chalk in oil reservoir, and therefore its behaviour can be very complicated. In this paper, a constitutive law is proposed for modelling the mechanical behaviour of a chalk saturated by two non-miscible fluids, water and oil. The effects of the capillary pressure or suction are taken into account. They are considered as an independent variable, as in the Barcelona's basic model developed for unsaturated soils. On the other hand, internal friction and pore collapse are modelled as independent mechanisms. The determination of the parameters is based on triaxial and oedometer tests. Finally, in order to validate the model, predictions are compared with experimental results of water-flooding test. Copyright (C) 2002 John Wiley Sons, Ltd. [less ▲]

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See detailMechanical behaviour of tape springs used in the deployment of reflectors around a solar panel
Dewalque, Florence ULg; Collette, Jean-Paul; Bruls, Olivier ULg

in Acta Astronautica (2016), 123

In order to increase the production of power on small satellites, solar panels are commonly deployed and, in some cases, reflectors are added to improve the concentration factor on solar cells. In this ... [more ▼]

In order to increase the production of power on small satellites, solar panels are commonly deployed and, in some cases, reflectors are added to improve the concentration factor on solar cells. In this work, reflectors are deployed by the means of compliant mechanisms known as tape springs. Their attractive characteristics are, among others, their passive behaviour, their self-locking capacity, their elastic deformations and their robustness. However, their mechanical behaviour is highly nonlinear and requires thorough analyses in order to develop predictive numerical models. It is shown here through parametric studies that the nonlinear behaviour of a tape spring is mainly governed by its geometry. Thus, for each specific application, its dimensions can be determined in order to minimise two critical features: the maximum stress affecting the structure and the maximum motion amplitude during deployment. In this paper, an optimisation procedure is proposed to meet these requirements. [less ▲]

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See detailMechanical behaviour of tape springs used in the deployment of reflectors around a solar panel
Dewalque, Florence ULg; Collette, Jean-Paul; Bruls, Olivier ULg

in Proceedings of the 6th International Conference on Mechanics and Materials in Design (M2D) (2015)

In order to increase the production of power on small satellites, large solar panels are commonly deployed and, in some cases, reflectors are added to improve the concentration factor on solar cells. In ... [more ▼]

In order to increase the production of power on small satellites, large solar panels are commonly deployed and, in some cases, reflectors are added to improve the concentration factor on solar cells. In this work, reflectors are deployed by the means of compliant mechanisms known as tape springs. Their attractive characteristics are, among others, their passive behaviour, their self-locking capacity, their elastic deformations and their robustness. It is shown here through parametric studies that the behaviour of a tape spring is mainly governed by its geometry. Thus, for each specific application, its dimensions must be determined in order to minimise two critical features: the maximum stresses affecting the structure and the maximum amplitudes of motion during deployment. In this paper, an optimisation procedure is proposed to meet these requirements. [less ▲]

Detailed reference viewed: 58 (7 ULg)
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See detailMechanical Buckling of Composite Panels with/without Cutouts
Pascan, Oana; Zhang, Weihong; Ponthot, Jean-Philippe ULg

in International Journal of Plant Engineering and Management (2012), 17(2), 65-76

A simpli ed analytical solution suitable for simple stacking sequences was developed using the Euler buckling theory, the structure's equations of equilibrium and laminate panel mathematical formulation ... [more ▼]

A simpli ed analytical solution suitable for simple stacking sequences was developed using the Euler buckling theory, the structure's equations of equilibrium and laminate panel mathematical formulation. Comparing these results with numerical results reveals the ac- curacy of the method and even more, allows us to validate the numerical analysis. Therefore, two important results are obtained : a simpli ed analytical solution for the buckling problem and vali- dation of the numerical results. Another important and novel nding is related to the in uence of the angle ply orientation and of the cutouts, on the buckling load. Under symmetrical boundary conditions and loading case, rectangular panels with elliptical cutouts, give better results for 90 oriented plies than for 0 oriented ones. With a compression load applied in the X direction, and with material properties 10 times better in X direction than in Y direction, the best results are obtained when the load is aligned with the Y direction associated to the material reference frame. Moreover, panels with cutouts seem to behave better than panels without cutouts under certain ply orientation angles. [less ▲]

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See detailMechanical characterization of porous structures by the combined use of micro-CT and in-situ loading
Kerckhofs, Greet ULg; Schrooten, Jan; Elicegui, Laida et al

Conference (2008)

Detailed reference viewed: 13 (2 ULg)
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See detailMechanical characterization of porous structures by the combined use of micro-CT and in-situ loading
Kerckhofs, Greet ULg; Schrooten, Jan; Elicegui, Laida et al

in Proceedings book WCNDT 2008 (2008)

Detailed reference viewed: 14 (4 ULg)
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See detailMechanical comparison of eight vertical jump exercises
Jidovtseff, Boris ULg; Cronin, John; Harris, Nigel et al

in Computer Methods in Biomechanics & Biomedical Engineering (2010, September), 13(S1), 77-78

Detailed reference viewed: 137 (18 ULg)
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See detailMechanical constitutive framework for thermal effects on unsaturated soils.
François, Bertrand ULg; Nuth, Mathieu; Laloui, Lyesse

in Proceeding of the 10th Int. Symp. on Numerical Models in Geomechanics, NUMOG X (2007)

Research interest in the thermo-mechanical behaviour of unsaturated soils is growing as a result of an increasing number of geomechanical problems involving both thermal and suction effects. The ... [more ▼]

Research interest in the thermo-mechanical behaviour of unsaturated soils is growing as a result of an increasing number of geomechanical problems involving both thermal and suction effects. The underground waste disposal is one such critical problem. Until now, these two environmental loadings have often been considered independently. This paper proposes a new unified thermo-mechanical framework for unsaturated soils based on thermo-hydro-mechanical (THM) experimental evidence on cohesive soils. The Bishop effective stress framework is adopted to represent the stress state in the soil in a unified fashion. This constitutive context based on the evolution of two key parameters (the preconsolidation pressure and the suction air-entry value) makes it possible to represent the main features of the thermo-mechanical behaviour of unsaturated soils. [less ▲]

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See detailThe mechanical control of peri-implant bone remodeling investigated by in vivo imaging and in silico modeling
Li, Zihui; Betts, Duncan; Kuhn, Gisela et al

Conference (2016, July)

Detailed reference viewed: 16 (1 ULg)