References of "Denoël, Vincent"
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See detailPrincipal static wind loads
Blaise, Nicolas ULg; Denoël, Vincent ULg

in Journal of Wind Engineering & Industrial Aerodynamics (2013), 113

In current wind design practice, static wind loads are usually defined to obtain, by simple static analyses, the extreme values of any structural response that would be formally obtained with a strict ... [more ▼]

In current wind design practice, static wind loads are usually defined to obtain, by simple static analyses, the extreme values of any structural response that would be formally obtained with a strict dynamic buffeting analysis. The minimum and maximum values that may reach any response define the envelope. Equivalent static wind loads (ESWLs) allow to recover extreme responses in the envelope. As a first objective, this paper formalizes a general method to determine ESWL, in a nodal basis, by extending the concept of load-response correlation, which is only valid in the background range. The general method, the displacement-response-correlation (DRC) method, covers the background and resonant contributions of the considered response. As a second objective, the paper addresses the problem of building a set of static wind loads that adequately reconstructs the envelopes of responses. The concept of principal static wind loads (PSWL) is introduced to form a reduced basis of representative loads well-suited for envelope reconstruction. Its optimality is demonstrated both analytically and with a detailed illustrative example. [less ▲]

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See detailDynamic Computation and Design of a World’s Record Death-Ride
Denoël, Vincent ULg; Canor, Thomas ULg; Demanet, Johan

in Proceedings of the 4th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (2013)

A death-ride is a long cable anchored between two dead ends, allowing the crossing of wide valleys. Besides these mobility purposes, it is also operated in rescue operations, or simply for leisure. From a ... [more ▼]

A death-ride is a long cable anchored between two dead ends, allowing the crossing of wide valleys. Besides these mobility purposes, it is also operated in rescue operations, or simply for leisure. From a serviceability viewpoint, a death-ride design should offer a comfortable and/or enjoyable journey to the riders, which is typically expressed in terms of maximum velocity. From a strength viewpoint, a death-ride should be designed in order to safely withstand the cable self-weight, wind forces, the rider’s load and at last but not least, the initial tension in the cable. Actually, the tensioning operation is usually subtle. Indeed, in case of a loose cable, the rider may be stopped in the in-span sagging area. Conversely a too tight cable will generate large stresses but also large outlet velocity at the end of the ride. The design of a death-ride is a tradeoff between all these aspects. The paper presents the dynamic model that was used for the design of a 1.2km long death-ride, with an only 10-mm diameter, a constraint fixed in the very first stages of this project for compatibility reasons, with the existing equipment. This death-ride, built and used in May 2010 in a Grimp competition [1], has a world record of the longest death-ride in urban area. The structural part of the dynamic model is rather common, with a co-rotational description of the cable by means of a chain-like model [2]. An interesting feature, however, concerns the interaction between the rider and the cable. In fact, because the pulley is rolling on the cable, the position of the force acting on the cable, resulting from the ride, depends on the rider’s velocity, which itself depends on the cable inclination. This coupling is solved in a staggered manner, and the details of the algorithm are given in the full paper. In some limiting cases, a comparison with analytical solutions is also provided, where these analytical solutions are available [3]. Experimental validation and observation of the operated death-ride will also be presented. [less ▲]

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See detailExtension of Davenport's Background/Resonant decomposition for the estimation of higher response moments
Denoël, Vincent ULg

in Proceedings of the Sixth European-African Conference on Wind Engineering (2013)

The non Gaussian buffeting analysis of a structure subjected to turbulent wind may be advantageously performed with a Volterra approach. Although this concept may be applicable to nonlinear structures ... [more ▼]

The non Gaussian buffeting analysis of a structure subjected to turbulent wind may be advantageously performed with a Volterra approach. Although this concept may be applicable to nonlinear structures, the scope of this paper is limited to structures with a deterministic linear behavior. In this case, the Volterra kernels take a simple explicit expression and the statistical moments of the structural response are simply recovered by a multi-dimensional integration of the corresponding spectra. Because the multi-dimensional spectra of the loading are usually determined numerically, these integrals have to be computed numerically too. The computational burden necessary for the estimation of these integrals turns out to be prohibitive as soon as high order moments are required (beyond and including 4th moment). The numerical conditioning is in fact again worse when the structural damping is low as the Volterra kernels then exhibit very large gradients in the frequency space, which are difficult to capture properly. Because the timescales related to the dynamics of the structure and to the random wind loading are well distinct, a nowadays customary decomposition of the response into Background and Resonant contributions (dating back to A. Davenport's earliest works) provides a very good estimation of the second statistical moment. Recently the concept has been extended to the Background/biResonant decomposition for the estimation of the third statistical moment of the response. This paper presents the extension to the computation of the fourth statistical moment, with the only assumptions of slight damping and low-frequency loading such as those that made Allan Davenport's Background/Resonant (B/R) decomposition fruitful. After some multiple scales considerations, the fourth moment of the response is approximated as the sum of a background component, a tetraresonant component and a mixed background-biresonant component. Mathematical developments will be presented in the full paper along with illustrative examples, while the current 4-page abstract just presents of a flavour of it. [less ▲]

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See detailElements de processus stochastiques
Denoël, Vincent ULg

Learning material (2013)

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See detailPatching Asymptotics Solution of a Cable with a Small Bending Stiffness
Denoël, Vincent ULg; Canor, Thomas ULg

in Journal of Structural Engineering (2013), 139

The analysis of a cable with a small bending stiffness is a problem encountered in many engineering applications such as the fatigue assessment of stay cables, the modeling of pipeline laying operation or ... [more ▼]

The analysis of a cable with a small bending stiffness is a problem encountered in many engineering applications such as the fatigue assessment of stay cables, the modeling of pipeline laying operation or the determination of bending stresses in drillpipe assemblies. Because this phenomenon is modeled by a singularly perturbed equation, standard numerical techniques fail to solve these problems efficiently. As an alternative, provided the complexity of the analytical developments does not preclude their application, these problems may be tackled with appealing analytical procedures such as matching asymptotics or multiple scales. Otherwise advanced numerical simulations combining patching asymptotics within a numerical framework are the only possible approach for problems where the governing equations are too complex. Patching asymptotics also features a number of merits such as the possibility of using a boundary layer with a finite extent. Aiming at a better understanding of this latter technique, it is considered here to determine the solution of a cable with a small bending stiffness. Interesting details about patchability conditions and about how to restore higher derivatives continuity are included. The accuracy of the patching asymptotics approach is also compared with that of matched asymptotics. [less ▲]

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See detailTransient Fokker-Planck equation with SPH method : Application in seismic design
Canor, Thomas ULg; Denoël, Vincent ULg

in Papadrakakis, M; Papadopoulos, V; Plevris, V (Eds.) Proceedings COMPDYN2013 (2013)

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See detailMerging multi-camera data to reduce motion analysis instrumental errors using Kalman filters
Schwartz, Cédric ULg; Denoël, Vincent ULg; Forthomme, Bénédicte ULg et al

in Computer Methods in Biomechanics and Biomedical Engineering (2013)

In motion capture systems, markers are often seen by multiple cameras. All cameras do not measure the position of the markers with the same reliability because of environmental factors such as the ... [more ▼]

In motion capture systems, markers are often seen by multiple cameras. All cameras do not measure the position of the markers with the same reliability because of environmental factors such as the position of the marker in the field of view or the light intensity received by the cameras. Kalman filters offer a general framework to take the reliability of the various cameras into account and consequently improve the estimation of the marker position. The proposed process can be applied to both passive and active systems. Several reliability models of the cameras are compared for the Codamotion active system, which is considered as a specific illustration. The proposed method significantly reduces the noise in the signal, especially at long range distances. Therefore, it improves the confidence of the positions at the limits of the field of view. [less ▲]

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See detailDominance effect on scapula 3-dimensional posture and kinematics in healthy male and female populations
Schwartz, Cédric ULg; Croisier, Jean-Louis ULg; Rigaux, Elise et al

in Journal of Shoulder and Elbow Surgery (2013), (0), -

Background: The contralateral shoulder is often used as a reference when evaluating a pathological shoulder. However literature provides contradictory results regarding the symmetry of the scapular ... [more ▼]

Background: The contralateral shoulder is often used as a reference when evaluating a pathological shoulder. However literature provides contradictory results regarding the symmetry of the scapular pattern in a healthy population. We assume that several factors including the gender and the type of motion may influence the scapula bilateral symmetry. Method: The dominant and non dominant shoulders of two populations of men and women composed of 11 subjects each were evaluated for three distinct motions: flexion in the sagittal plane, abduction in the frontal plane and gleno-humeral internal/external rotation with the arm abducted at 90°. Posture, kinematic and range of motion were studied separately. Results: Asymmetries are observed for motions performed in the frontal and sagittal plane but not for the internal/external rotation with the arm abducted at 90°. Multiplane asymmetries are observed for the male population, whereas asymmetries for the female one are mainly uniplanar. For both men and women, the scapula has a larger upward rotation on the dominant side. For men, a larger posterior tilt is also observed. The asymmetries mainly originate in the scapula kinematic and not in its original posture. Discussion: Even if the asymmetries are not large in terms of amplitude (inferior to 5°), one should be aware of their existence and the influence of the composition of the studied population when using the contralateral shoulder as a reference. [less ▲]

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See detailShoulder injury prevention in sports using 3D motion capture
Schwartz, Cédric ULg; HAZEE, Amandine ULg; Denoël, Vincent ULg et al

Poster (2012, December 07)

In sports, where regular and intensive training could progressively lead to traumatic situations, accurate measurement of kinematic parameters can help to predict and anticipate injuries. Overhead ... [more ▼]

In sports, where regular and intensive training could progressively lead to traumatic situations, accurate measurement of kinematic parameters can help to predict and anticipate injuries. Overhead throwing athletes may develop an increased stiffness of the shoulder capsule. The resulting diminution of the gleno-humeral range of motion is usually associated with decreased performance and injury risks. This study illustrates the detection of these situations that put the athlete at risk. [less ▲]

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See detailValidated Extraction of Gait Events from 3D Accelerometer Recordings
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Stamatakis, Julien et al

in IEEE International Conference on 3D Imaging (IC3D) (2012, December)

This work is part of a project that deals with the three-dimensional (3D) analysis of normal and pathological gaits based on a newly developed system for clinical applications, using low-cost wireless ... [more ▼]

This work is part of a project that deals with the three-dimensional (3D) analysis of normal and pathological gaits based on a newly developed system for clinical applications, using low-cost wireless accelerometers and a signal processing algorithm. This system automatically extracts relevant gait events such as the heel strikes (HS) and the toe-offs (TO), which characterize the stance and the swing phases of walking. The performances of the low-cost accelerometer hardware and related algorithm have been compared to those obtained by a kinematic 3D analysis system and a force plate, used as gold standard methods. The HS and TO times obtained from the gait data of 7 healthy volunteers (147 trials) have been found to be (mean ± standard deviation) 0.42±7.92 ms and 3.11±10.08 ms later than those determined by the force plate, respectively. The experimental results demonstrate that the new hardware and associated algorithm constitute an effective low-cost gait analysis system, which could thus be used for the assessment of mobility in routine clinical practice. [less ▲]

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See detailPrincipal Static Wind Loads on a large roof structure
Blaise, Nicolas ULg; Hamra, Lotfi ULg; Denoël, Vincent ULg

in Proceedings of the 12th ANIV conference of wind engineering In Vento (2012, October 07)

Usually, structural wind design is realized using static wind loads. Such loadings are expected, as a main property, to recover by static analyses, the envelope values that would be obtained by a formal ... [more ▼]

Usually, structural wind design is realized using static wind loads. Such loadings are expected, as a main property, to recover by static analyses, the envelope values that would be obtained by a formal buffeting analysis. For simple structures, equivalent static wind loads might be used but they are established in order to reproduce envelope values of specific structural responses and are thus not suitable to reconstruct efficiently the entire envelope. Recently, more general methods were derived to propose global static loadings that reconstruct the entire envelope but several drawbacks remained as their robust applicability for any structure and accuracy. This paper addresses a new type of static loadings, the principal static wind loads, derived in a strict mathematical way, the singular value decomposition, to make it optimum for the envelope reconstruction problem. The method is illustrated with a large roof and the reconstruction accuracy is analysed by studying the rate of envelope reconstruction, envelope previously obtained by a rigourous stochastic analysis. The way principal loadings are derived makes them suitable for combinations in order to increase the rate of the envelope reconstruction. As a major outcome, the method provides a finite number of design load cases that matches a desired level of accuracy in the envelope reconstruction. [less ▲]

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See detailIntroduction aux statistiques et probabilités
Denoël, Vincent ULg

Learning material (2012)

Le document annexé contient les slides du cours donné en 2012-2013 aux étudiants du 3eme Bac Ingénieur Architectes de l'Université de Liège. Le cours est donné en 30 heures.

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See detailIntroduction aux statistiques et probabilités
Denoël, Vincent ULg

Learning material (2012)

Le document annexé contient les slides du cours donné en 2012-2013 aux étudiants du 3eme Bac Ingénieur Architectes de l'Université de Liège. Le cours est donné en 30 heures.

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See detailNonlinear Dynamics Of A Drill Bit Under Percussive Activation
Depouhon, Alexandre ULg; Denoël, Vincent ULg; Detournay, Emmanuel

in Proceedings of ICTAM 2012, Beijing (2012, August)

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See detailLimit cycling behavior of a hybrid system: Application to percussive drilling
Depouhon, Alexandre ULg; Detournay, Emmanuel; Denoël, Vincent ULg

in Proceedings of the 2nd International Colloquium on Non-Linear Dynamics and Control of Deep Drilling Systems, Eindhoven, May 2012 (2012, May)

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See detailExtensions of the Background/biResonant decomposition
Denoël, Vincent ULg

Poster (2012)

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See detailStructural Dynamics
Denoël, Vincent ULg

Learning material (2012)

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See detailThe concept of numerical admittance
Denoël, Vincent ULg; Maquoi, René ULg

in Archive of Applied Mechanics (2012)

The reconstruction of a discretized random distributed loading, as the wind pressure from some measurement taps, is usually performed by simple or advanced interpolation between the nodes of the mesh ... [more ▼]

The reconstruction of a discretized random distributed loading, as the wind pressure from some measurement taps, is usually performed by simple or advanced interpolation between the nodes of the mesh. This results in an overestimation of the coherence of the loading, especially in the high frequency range where the loading typically shows less coherence. An expensive way to circumvent this issue is to make the mesh denser. This is however not always possible, in particular in experimental testing where there is usually a limited number of available measurement spots. The concept of numerical admittance is introduced in order to rectify this inaccurate estimation of the resulting loading in the high-frequency range. It is actually introduced as a legitimate way of reducing the loading in accordance with the looseness of the discretisation mesh. Another major advantage of the concept is the opportunity to determine adequately the mesh size independently from the correlation length scale. [less ▲]

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See detail3D Analysis of Normal and Pathological Gait Based on Low-Cost Wireless Accelerometers
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Bruls, Olivier ULg et al

in URSI Benelux Forum 2012 “Antennas: multiple designs, multiple applications” (2012)

We describe the principle and use of a new low-cost, wireless, 3-axis accelerometer-based device that records acceleration signals and automatically analyses them to characterize normal and pathological ... [more ▼]

We describe the principle and use of a new low-cost, wireless, 3-axis accelerometer-based device that records acceleration signals and automatically analyses them to characterize normal and pathological gait. [less ▲]

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See detailEfficient uncoupled stochastic analysis with non-proportional damping
Canor, Thomas ULg; Blaise, Nicolas ULg; Denoël, Vincent ULg

in Journal of Sound & Vibration (2012), 331(2012), 52835291

The use of normal modes of vibration in the analysis of structures with nonproportional damping reduces the size of the resulting set of governing equations, but does not decouple them. A common practice ... [more ▼]

The use of normal modes of vibration in the analysis of structures with nonproportional damping reduces the size of the resulting set of governing equations, but does not decouple them. A common practice consists in decoupling the equations by disregarding the o -diagonal elements in the modal damping matrix. Recently, an approximation based on an asymptotic expansion of the modal transfer matrix has been proposed in a deterministic framework to partially account for o -diagonal terms, but still with a set of uncoupled equations. This paper aims at extending this method in a stochastic context. First the mathematical background is introduced and the method is illustrated with a simple example. Then its relevance is demonstrated within the context of the structural analysis of a large and realistic structure. [less ▲]

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