Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailDesign of hollow joints using the component method
Jaspart, Jean-Pierre ULg; Weynand, Klaus

in Proceedings of the 15th international symposium on tubular structures ISTS15 (2015, May)

The component method is a design approach for the characterization of the mechanical proper- ties of structural joints. initially the component method has been developed for joints between open sections ... [more ▼]

The component method is a design approach for the characterization of the mechanical proper- ties of structural joints. initially the component method has been developed for joints between open sections and it is referred to in Eurocode 3 Part 1.8. It allows a theoretical evaluation of the resistance, stiffness and ductility properties based on mechanical models. However, the design of joints between tubular hollow sections follows a different approach. A joint (or more precisely a joint configuration, i.e. a zone where two or more members are connected) is considered as a whole when determining its resistance(s). Existing design rules for joints between tubular hollow sections are based on simple theoretical mechanical models and they are then fitted through comparisons with experimental tests. As a consequence, their field of application is often restricted to the domain for which the rules have been validated. Under the umbrella of CIDECT, a project is being carried out to develop a unified design approach for steel joints independent of the type of section of the connected elements by extending the field of application of the “component method”. To achieve this objective, rules recommended for hollow section joints have to be “converted” into a component format. The present paper presents ways and means for the development of such a unified design approach. Components have been identified in typical hollow section joints in lattice girder structures. The paper presents also design rules (component resistances and assembly rules) for some hollow section joints as examples. [less ▲]

Detailed reference viewed: 24 (3 ULg)
Full Text
Peer Reviewed
See detailDesign of hybrid nanovehicles for remotely triggered drug release: an overview
Liu, Ji; Detrembleur, Christophe ULg; Mornet, Stéphane et al

in Journal of Materials Chemistry B (2015), 3(30), 6117-6147

n the past few decades, various nanovehicles have been developed as drug delivery systems, in which inorganic and organic components are integrated within a nano-object. Upon the application of remote ... [more ▼]

n the past few decades, various nanovehicles have been developed as drug delivery systems, in which inorganic and organic components are integrated within a nano-object. Upon the application of remote stimuli, e.g. alternating magnetic field, near infrared or ultrasound radiations, the release of guest molecules can be triggered in a quite controlled manner. Herein, we review different hybrid nanostructures which have already been reported for the remotely triggered release, such as those based on (1) host–guest conjugates, (2) core–corona nanoparticles, (3) polymer nanogels, (4) polymer micelles, (5) liposomes, (6) mesoporous silica particles and (7) hollow nanoparticles. Moreover, we also summarize six underlying mechanisms that govern such a kind of remotely triggered release behaviours: (1) enhanced diffusion and/or permeation, (2) thermo- or photo-labile bond cleavage, (3) fusion of phase-changed materials, (4) photo-induced isomerisation, (5) thermo-induced swelling/de-swelling of thermo-responsive polymers, and (6) destruction of the nanostructures. The ways in which different components are incorporated into an integrated hybrid nanostructure and how they contribute to the remotely triggered release behaviours are detailed. [less ▲]

Detailed reference viewed: 73 (4 ULg)
Full Text
Peer Reviewed
See detailDesign of IMEPS (Ipriflavone Multicentric European Fracture Study)
Reginster, Jean-Yves ULg; Roux, Ch; Riis, BJ

in Osteoporosis International (1996), 6(S1), 318

Detailed reference viewed: 14 (2 ULg)
Full Text
Peer Reviewed
See detailDesign of Innovative Ship Concepts Using an Integrated Decision Support System for Ship Production and Operation
Rigo, Philippe ULg; Žanić, Vedran; Ehlers, Sören et al

in Brodogradnja : Journal of Naval Architecture and Shipbuilding Industry (2010), 61(4), 367-381

Design of Innovative Ship Concepts Using an Integrated Decision Support System for Ship Production and Operation

Detailed reference viewed: 168 (10 ULg)
Full Text
See detailDesign of interactive visualization of models and students data
Mazza, R; Mazzola, L; Glahn, C et al

Report (2009)

This document reports the design of the interactive visualizations of open student models that will be performed in GRAPPLE. The visualizations will be based on data stored in the domain model and student ... [more ▼]

This document reports the design of the interactive visualizations of open student models that will be performed in GRAPPLE. The visualizations will be based on data stored in the domain model and student model, and aim at supporting learners to be more engaged in the learning process, and instructors in assisting the learners. [less ▲]

Detailed reference viewed: 63 (2 ULg)
See detailDesign of joints i steel and composite structures
Jaspart, Jean-Pierre ULg; Weynand, Klaus

Book published by Ernst & Sohn, a Wiley brand (2016)

Detailed reference viewed: 35 (3 ULg)
Full Text
Peer Reviewed
See detailDesign of joints in industrial portal frames made of slender built-up members
Braham, M.; Jaspart, Jean-Pierre ULg

in Proceedings of the International Conference on Experimental Model, research and testing of thin-Walled Structures (1997)

Detailed reference viewed: 23 (1 ULg)
Full Text
See detailDesign of Load Shedding Schemes against Voltage Instability
Moors, Cedric; Lefebvre, Daniel; Van Cutsem, Thierry ULg

(2000, January 27)

This paper proposes a methodology for the design of automatic load shedding against long-term voltage instability. In a first step, a set of training scenarios is set up, corresponding to various ... [more ▼]

This paper proposes a methodology for the design of automatic load shedding against long-term voltage instability. In a first step, a set of training scenarios is set up, corresponding to various operating conditions and disturbances. Each scenario is analyzed to determine the minimal load shedding which stabilizes the system, with due consideration for the shedding location and delay. In a second step, the parameters of a closed-loop undervoltage load shedding scheme are determined so as to: (i) approach as closely as possible the optimal sheddings computed in the first step, over the whole set of scenarios; (ii) stabilize the system in all the unstable scenarios and (iii) shed no load in the stable ones. The corresponding optimization problem is solved using a (micro-)Genetic Algorithm. A detailed example is given on the Hydro-Quebec system in which load shedding is presently planned. [less ▲]

Detailed reference viewed: 77 (3 ULg)
Full Text
See detailDesign of Load Shedding Schemes against Voltage Instability using Combinatorial Optimization
Van Cutsem, Thierry ULg; Moors, Cedric; Lefebvre, Daniel

(2002, January 31)

This paper proposes a methodology for the design of automatic load shedding against voltage instability. In a first step, we describe a method allowing to find the minimal shedding required in a given ... [more ▼]

This paper proposes a methodology for the design of automatic load shedding against voltage instability. In a first step, we describe a method allowing to find the minimal shedding required in a given unstable scenario. In a second step, we describe the structure of various controllers and identify the parameters to be optimized. Next, we present an optimization approach to find the controller parameters which optimize an overall performance objective. Results are presented on the Hydro-Québec system, in which load shedding is presently planned. [less ▲]

Detailed reference viewed: 78 (4 ULg)
Full Text
See detailDesign of macroporous poly(ionic liquid)s by CO2/water emulsion templated polymerization
Boyère, Cédric ULg; Favrelle, Audrey; Boury, Frank et al

Poster (2013, November 20)

Detailed reference viewed: 22 (4 ULg)
Full Text
See detailDesign of mechanism components using topology optimization and flexible multibody simulation
Bruls, Olivier ULg; Lemaire, Etienne ULg; Eberhard, Peter et al

in Proceedings of the 8th World Congress on Computational Mechanics (2008, July)

This work addresses the topology optimization of structural components embedded in multibody systems with large amplitude motions. For example, in deployable space structures, piston engines, automotive ... [more ▼]

This work addresses the topology optimization of structural components embedded in multibody systems with large amplitude motions. For example, in deployable space structures, piston engines, automotive suspensions, robots and high-speed machine-tools, the articulated components undergo large displacements and elastic deformations, and are subject to transient loads and nonlinear dynamic effects. The performance of such systems often depends on the mechanical design in a non-intuitive way. <br />Several researchers have addressed the optimization of the geometric parameters of mechanisms and also of the connectivity of mechanisms made of rigid members. In contrast, topology optimization techniques are often based on continuum mechanics assumptions, and usually aim at optimizing the layout of an isolated structural component under the assumption of small displacements and small deflections. In order to apply topology optimization to mechanism components, one may consider that each structural component is isolated from the rest of the mechanism and use simplified quasi-static load cases to mimic the complex loadings in service. However, two main drawbacks are associated with this approach. Firstly, defining the equivalent load cases is a rather difficult task, which is often based on trials and errors and which requires some expertise. Secondly, topology optimization is often sensitive to loading conditions, especially for multiple load cases and stress constraints, so that the optimal character of the resulting design becomes questionable if the loading is approximative. For these reasons, in order to obtain better optimal layouts, this paper proposes an optimization procedure based on dynamic simulations of the full flexible multibody system. <br />For this purpose, the nonlinear finite element approach is selected for the modelling and the simulation of the flexible multibody system. The present work is thus similar to the usual approach used in topology optimization in which the continuum domain is discretized into finite elements. The nonlinear finite element formalism accounts for both large rigid-body motions and elastic deflections of the structural components. The design variables are classically density-like parameters associated to a power law interpolation of effective material properties for intermediate densities, also known as Simply Isotropic Material with Penalization (SIMP). <br />The nonlinear equations of motion are solved using a generalized-alpha time integration scheme, and the sensitivity analysis of mechanical responses is based on a direct differentiation method. The efficient solution of the optimization problem relies on the sequential convex programming concept at the core of the CONLIN software. <br />In the present study, the method is applied to various types of mechanical systems. Firstly, planar mechanisms with truss structural components are considered. Each truss is represented by a structural universe of beams with a topology design variable attached to each one. Secondly, the discussion is extended to similar mechanisms with 3D motions. Finally, the topology optimization of spatial bodies represented by 3D finite element meshes is considered. [less ▲]

Detailed reference viewed: 113 (11 ULg)
See detailDesign of mechatronic systems with variable mechanical configuration
Da Silva, Maira; Bruls, Olivier ULg; Desmet, Wim et al

in Proceedings of the 9th International Conference on Motion and Vibration Control (MOVIC) (2008, September)

Some mechatronic systems have different spatial configurations or operation positions, and, as a consequence, their dynamic behavior, described by their most significant eigenfrequencies and mode-shapes ... [more ▼]

Some mechatronic systems have different spatial configurations or operation positions, and, as a consequence, their dynamic behavior, described by their most significant eigenfrequencies and mode-shapes, may vary in the configuration space. This inevitably affects the performance and the stability of the control system. Regarding the design of mechatronic systems with variable configuration, two main issues are treated in this paper: (i) the derivation of a parametric model able to capture the varying dynamics and the control actions, (ii) the integrated design of the structure and the controller. To cope with these issues, a parametric model is derived using a flexible multibody system technique based on the finite element method. A global modal parameterization is applied for model-order reduction, yielding a concise description of the flexible multibody model. A linear parameter varying controller is derived via interpolation of local controllers for the reduced models. This methodology is applied to a pick-and-place assembly robot with a gripper carried by a flexible beam. Eventually, design tradeoffs are evaluated considering the performance of the active system for different structural configurations. [less ▲]

Detailed reference viewed: 70 (0 ULg)
Full Text
Peer Reviewed
See detailDesign of mesoporous carbon fibers from a poly(acrylonitrile) based block copolymer by a simple templating compression moulding process
Thomassin, Jean-Michel ULg; Debuigne, Antoine ULg; Jérôme, Christine ULg et al

in Polymer (2010), 51(14), 2965-2971

Mesoporous carbon fibers were prepared by controlled pyrolysis of poly(vinyl acetate)-b-poly(acrylonitrile) (PVAc-b-PAN) copolymer located inside a cylindrical nanoporous template. A melt-compression ... [more ▼]

Mesoporous carbon fibers were prepared by controlled pyrolysis of poly(vinyl acetate)-b-poly(acrylonitrile) (PVAc-b-PAN) copolymer located inside a cylindrical nanoporous template. A melt-compression method was developed to help the penetration of the infusible copolymer inside the template without the use of any solvent that ensures the formation of completely filled fibers instead of nanotubes. The influence of the composition of the PVAc-b-PAN copolymer and the heating rate during pyrolysis on the porous morphology of the fibers was studied by transmission electron microscopy (TEM). [less ▲]

Detailed reference viewed: 110 (7 ULg)
Full Text
See detailDesign of Microswitch Systems Avoiding Stiction due to Surface Contact
Wu, Ling ULg; Noels, Ludovic ULg; Rochus, Véronique et al

in Proulx, Tom (Ed.) MEMS and Nanotechnology, Volume 2 (2011)

Stiction which results from contact between surfaces is a major failure mode in micro electro-mechanical systems (MEMS). Increasing restoring forces using high spring constant allows avoiding stiction but ... [more ▼]

Stiction which results from contact between surfaces is a major failure mode in micro electro-mechanical systems (MEMS). Increasing restoring forces using high spring constant allows avoiding stiction but leads to an increase of the actuation voltage so that the switch’s efficiency is threatened. A statistical rough surfaces interaction model, based on Maugis’ and Kim’s formulations is applied to estimate the adhesive forces in MEMS switches. Based on the knowledge of these forces, the proper design range of the equivalent spring constant, which is the main factor of restoring force in MEMS switches, can be determined. The upper limit of equivalent spring constant depends mainly on the expected actuator voltage and on the geometric parameters, such as initial gap size and thickness of dielectric layer. The lower limit is assessed on the value of adhesive forces between the two contacting rough surfaces. It mainly depends on the adhesive work of contact surfaces and on the surfaces’ roughness. In order to study more complicated structures, this framework will be used in a multiscale model: resulting unloading micro adhesive contact-distance curves of two rough surfaces will be used as contact forces in a finite-element model. In this paper the extraction of these curves for the particular case of gold to gold micro-switches is pursued. [less ▲]

Detailed reference viewed: 92 (24 ULg)
Full Text
See detailDesign of Microswitch Systems Avoiding Stiction due to Surface Contact
Wu, Ling ULg; Noels, Ludovic ULg; Rochus, Véronique ULg et al

in SEM 2010 Annual Conference & Exposition on Experimental and Applied Mechanics (2010)

Stiction which results from contact between surfaces is a major failure mode in micro electro-mechanical systems (MEMS). Increasing restoring forces using high spring constant allows avoiding stiction but ... [more ▼]

Stiction which results from contact between surfaces is a major failure mode in micro electro-mechanical systems (MEMS). Increasing restoring forces using high spring constant allows avoiding stiction but leads to an increase of the actuation voltage so that the switch’s efficiency is threatened. A statistical rough surfaces interaction model, based on Maugis’ and Kim’s formulations is applied to estimate the adhesive forces in MEMS switches. Based on the knowledge of these forces, the proper design range of the equivalent spring constant, which is the main factor of restoring force in MEMS switches, can be determined. The upper limit of equivalent spring constant depends mainly on the expected actuator voltage and on the geometric parameters, such as initial gap size and ,thickness of dielectric layer. The lower limit is assessed on the value of adhesive forces between the two contacting rough surfaces. It mainly depends on the adhesive work of contact surfaces and on the surfaces’ roughness. In order to study more complicated structures, this framework will be used in a multiscale model: resulting unloading micro adhesive contact-distance curves of two rough surfaces will be used as contact forces in a finite-element model. In this paper the extraction of these curves for the particular case of gold to gold micro-switches is pursued. [less ▲]

Detailed reference viewed: 171 (43 ULg)
Full Text
Peer Reviewed
See detailDesign of Movable Weirs and Storm Surge Barriers
Rigo, Philippe ULg; Abdelnour, R.; Bulckaen, D. et al

in PIANC 2006, 31ème Congrès de l’PIANC (Article 031) (2006, May)

Detailed reference viewed: 91 (3 ULg)