References of "Denoël, Vincent"
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See detailPressure-impulse diagram of a beam developing non-linear membrane action under blast loading
Hamra, Lotfi ULg; Demonceau, Jean-François ULg; Denoël, Vincent ULg

in International Journal of Impact Engineering (2015), 86

The p–I diagram of a frame beam subjected to blast loading is established, including the elastic lateral restraint and inertia offered by the rest of the structure, the development of nonlinear membrane ... [more ▼]

The p–I diagram of a frame beam subjected to blast loading is established, including the elastic lateral restraint and inertia offered by the rest of the structure, the development of nonlinear membrane action and also, the bending-tension (M−N) interaction that develops in the plastic hinges. The analytical procedures to compute the asymptotes in the p–I diagram as well as a parametric study on the p–I diagram are provided. A dimensional analysis of the problem reveals that, under the considered assumptions, four dimensionless parameters mainly influence the required ductility of the beam. Two of them are related to the behavior of the indirectly affected part (the lateral restraint and mass). Another one is related to the mechanical properties of the investigated beam (i.e. the ratio of the bending to axial resistance). The last parameter incorporates scales of the geometry and of the deformed configuration at the onset of the plastic mechanism. [less ▲]

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See detailEssentials of actions
Cerfontaine, Benjamin ULg; Collin, Frédéric ULg; Denoël, Vincent ULg et al

Learning material (2015)

This document deals with the philosophy of safety in civil engineering structures, including loads and load combinations to be applied when designing a structure. It contains general concepts that are ... [more ▼]

This document deals with the philosophy of safety in civil engineering structures, including loads and load combinations to be applied when designing a structure. It contains general concepts that are presented and discussed as well as values for some important input data that can be used as order of magnitude in the initial phase of a project. [less ▲]

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See detailProgramme d'étirement appliqué à l'épaule raide : conséquences fonctionnelles
Forthomme, Bénédicte ULg; Croisier, Jean-Louis ULg; COLLIGNON, Pierre ULg et al

Conference (2015, October 09)

Les athlètes de lancer présentent une mobilité passive gléno-humérale de l’épaule dominante spécifique avec une majoration de la rotation externe et une limitation de la rotation interne. La limitation ... [more ▼]

Les athlètes de lancer présentent une mobilité passive gléno-humérale de l’épaule dominante spécifique avec une majoration de la rotation externe et une limitation de la rotation interne. La limitation interne semble liée à une raideur capsulo-musculaire postérieure, favorisant les pathologies de l’épaule sportive. Matériel et méthodes Vingt hommes, sportifs d’armer / lancer (volley-ball, handball) et pratiquant au moins 6 heures d’entraînement depuis plus de 5 années ont participé à cette étude. Ils présentaient tous une raideur des structures postérieures évaluée en clinique. Lors de l’inclusion dans l’étude, 10 athlètes (22,5 ± 4 ans) étaient asymptomatiques, 10 (24,8 ± 4 ans) présentaient une épaule dominante symptomatique (≥ 3/10 sur l’EVA). Les athlètes ont étiré chaque jour leur épaule dominante (sleeper stretch et cross body arm) pendant 4 semaines (5 x 30’'). Avant et après le programme d’étirement des structures postérieures, ils ont subi un test isocinétique de force maximale des rotateurs internes et externes ainsi qu’une analyse tridimensionnelle définissant la cinématique scapulaire. Résultats Après 4 semaines d’étirement des structures postérieures, tous les athlètes ont montré un gain significatif de mobilité en rotation interne passive. Nous n’observons aucune modification de la cinétique scapulaire lors de l’analyse 3D après les étirements chez les athlètes asymptomatiques ; les athlètes symptomatiques présentent une diminution du tilt antérieur scapulaire au repos après les 4 semaines. L’évaluation isocinétique des rotateurs d’épaules après les étirements montrent uniquement une légère réduction (- 4% ; p < 0,05) de la force des rotateurs internes à 60°/s en concentrique chez les athlètes asymptomatiques. Les sportifs qui décrivaient des douleurs avant les étirements sont significativement améliorés après le programme de 4 semaines ; cette diminution de la douleur est corrélée au gain en rotation interne passive. Discussion L’étirement pendant 4 semaines des structures postérieures de l’épaule raide sportive permet une augmentation de la mobilité passive. Ce gain de mobilité est corrélé à la diminution de la douleur chez les athlètes symptomatiques. [less ▲]

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See detailEffect of a stretching program on overhead athletes with a stiff and painful shoulder
Schwartz, Cédric ULg; Croisier, Jean-Louis ULg; Bruls, Olivier ULg et al

Conference (2015, July 01)

Overhead athletes are more at risk of suffering shoulder injuries or/and developing shoulder pain. Stretching programs have been shown to successfully reduce pain for this population. However no study has ... [more ▼]

Overhead athletes are more at risk of suffering shoulder injuries or/and developing shoulder pain. Stretching programs have been shown to successfully reduce pain for this population. However no study has provided a global overview of the effects of stretching. The present study evaluated the evolution of the pain, the strength of the shoulder muscles, potential instabilities or lesion of the shoulder as well as the 3D scapular kinematics of 10 overhead athletes having a painful and stiff dominant shoulder. Our results show a significant decrease of the pain and of the positive impingement syndrome tests. The kinematics of the scapula reveals a more upward rotation of the scapula after the stretching, which may reduce the risk of sub-acromial conflicts. The strength of the internal and external rotators of the shoulder is not modified by the program. [less ▲]

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See detailBiomechanical Analysis of Abdominal Injury in Tennis Serves. A Case Report
Tubez, François ULg; Forthomme, Bénédicte ULg; Croisier, Jean-Louis ULg et al

in Journal of Sports Science & Medicine (2015), 14

The serve is an important stroke in any high level tennis game. A well-mastered serve is a substantial advantage for players. However, because of its repeatability and its intensity, this stroke is ... [more ▼]

The serve is an important stroke in any high level tennis game. A well-mastered serve is a substantial advantage for players. However, because of its repeatability and its intensity, this stroke is potentially deleterious for upper limbs, lower limbs and trunk. The trunk is a vital link in the production and transfer of energy from the lower limbs to the upper limbs; therefore, kin-ematic disorder could be a potential source of risk for trunk injury in tennis. This research studies the case of a professional tennis player who has suffered from a medical tear on the left rectus abdominis muscle after tennis serve. The goal of the study is to understand whether the injury could be explained by an inappropriate technique. For this purpose, we analyzed in three dimensions the kinematic and kinetic aspects of the serve. We also performed isokinetic tests of the player’s knees. We then compared the player to five other professional players as refer-ence. We observed a possible deficit of energy transfer because of an important anterior pelvis tilt. Some compensation made by the player during the serve could be a possible higher abdominal contraction and a larger shoulder external rotation. These partic-ularities could induce an abdominal overwork that could explain the first injury and may provoke further injuries. [less ▲]

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See detailHow biomechanical analysis may help to identify abdominal injury causes in high level tennis
Tubez, François ULg; Forthomme, Bénédicte ULg; Croisier, Jean-Louis ULg et al

Conference (2015, July)

This research studies the case of a professional tennis player who has suffered from a medical tear on the left rectus abdominis muscle after a tennis serve. The goal of the study is to understand whether ... [more ▼]

This research studies the case of a professional tennis player who has suffered from a medical tear on the left rectus abdominis muscle after a tennis serve. The goal of the study is to understand whether the injury could be explained by an inappropriate technique. For this purpose, we analyzed the three dimensions kinematic and kinetic of the serve. We also performed isokinetic tests of the knees. We compared the player to five other professional players. We observed a possible deficit of energy transfer because of an important anterior pelvis tilt. Some compensations of the player during serve could be a possible higher abdominal contraction and a larger shoulder external rotation. These particularities could induce an abdominal overwork that would explain the first injury and may provoke a new injury. [less ▲]

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See detailComparison of experimental results and numerical modelling of unreinforced load-bearing masonry structures subjected to earthquake loading
Mordant, Christophe ULg; Denoël, Vincent ULg; Degée, Hervé

in Proceedings of the SECED 2015 Conference: Earthquake Risk and Engineering towards a Resilient World (2015, July)

This paper presents a comparison of experimental tests results on unreinforced load-bearing masonry structures subjected to earthquake loading with numerical predictions. First, simple walls are submitted ... [more ▼]

This paper presents a comparison of experimental tests results on unreinforced load-bearing masonry structures subjected to earthquake loading with numerical predictions. First, simple walls are submitted to cyclic and shaking table tests. Some of them include soundproofing devices in order to investigate their influence on the general behaviour in static and dynamic conditions. Additional walls with an opening and T-shaped walls are then tested under cyclic loading. The study is focused on the frame effect, the contribution of the perpendicular wall to the global strength and the efficiency of the connection. These aspects are also studied through shaking table tests on two masonry frames with T- or L-shaped piers. The main information is expressed in terms of force-displacement curves, mechanical properties and energy dissipation for the cyclic tests. The shaking table tests provide results in terms of dynamic and mechanical properties. Comparison of the results with numerical predictions is finally performed thanks to the software TREMURI. [less ▲]

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See detailAdjusted Equivalent Static Wind Loads for non-Gaussian linear static analysis
Blaise, Nicolas ULg; Denoël, Vincent ULg

in Proceedings of the 14th International Conference on Wind Engineering (2015, June)

In this paper, we propose a parametric bi-cubic model for the joint probability distribution of wind aerodynamic pressures and structural responses. This non-Gaussian model is a bivariate extension of the ... [more ▼]

In this paper, we propose a parametric bi-cubic model for the joint probability distribution of wind aerodynamic pressures and structural responses. This non-Gaussian model is a bivariate extension of the well-known Hermite polynomial transformation. It offers a new way to determine Equivalent Static Wind Loads, with the embedded feature to –at least partly– capture the non-Gaussianity of the aerodynamic pressures and responses. In a second step, based on the observation that this model as well as the usual LRC method or the conditional sampling technique, fail in reproducing structural responses that do not overestimate the extreme values resulting from a complete structural analysis, we propose a two-step adjustment procedure that restores the non-overestimation condition and the recovery of the considered structural response. With the example of a boundary layer flow around a duo-pitched roof, it is demonstrated that the Equivalent Static Wind Loads, adjusted or not, obtained with the proposed model of non-Gaussian joint probability density function reconstruct the envelope of structural response more efficiently than with the other two techniques. [less ▲]

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See detailRocking behaviour of simple unreinforced load-bearing masonry walls including soundproofing rubber layers
Mordant, Christophe ULg; Denoël, Vincent ULg; Degée, Hervé

in Proceedings of 5th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (2015, May)

This paper compares experimental measurements with predictions of different rocking models. These comparisons are carried out on the base of recent experimental results obtained by shake-table tests of ... [more ▼]

This paper compares experimental measurements with predictions of different rocking models. These comparisons are carried out on the base of recent experimental results obtained by shake-table tests of four simple unreinforced load-bearing clay masonry walls that have exhibited a significant rocking behaviour for the highest acceleration inputs. In a first stage, the simple model proposed by Housner is used after slight modifications needed to properly consider the actual mass distribution. Two parameters are identified as governing the model response, namely the criterion defining the initiation of motion and the restitution coefficient. Then, a two stacked blocks model is developed and solved by an event-driven strategy. This two-block model is intended to allow a better description of the behaviour of tested specimens through a more precise modelling of the additional mass. Finally, the pres-ence of rubber layers positioned at the top and bottom of two of the tested walls with the pur-pose of improving their acoustic behaviour required the development of an updated rocking model with viscous and flexible interfaces at the base of the wall and between the two stacked blocks. The properties of these interfaces are deduced from experimental data and their sig-nificant influence on the response is evidenced. [less ▲]

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See detailResearch Self-Evaluation Report of the Department ArGEnCo
Collin, Frédéric ULg; Dewals, Benjamin ULg; Elsen, Catherine ULg et al

Report (2015)

Evaluation is nowadays a general trend in the European Universities. At the University of Liège, the evaluation process is threefold: fist there is the evaluation of the bachelor and master degrees, then ... [more ▼]

Evaluation is nowadays a general trend in the European Universities. At the University of Liège, the evaluation process is threefold: fist there is the evaluation of the bachelor and master degrees, then the second evaluation concerns the internal administrations and finally Research activities are being evaluated. This quality policy at the different levels of the Institution is organized by the Vice-Rector for Quality, Pr. Freddy Coignoul and the SMAQ service (Service de Management et d’Accompagnement à la Qualité), which aims to promote, coordinate and disseminate within the University of Liège a culture of the Quality, founded on the values of the Institution. The Research assessment is a procedure undertaken by the University in order to promote the quality of the research in the Departments or research centres. Within the Faculty of Applied Sciences, the evaluation of the Bachelor and Master degrees in Engineering was carried out in 2013 by the AEQES (Agence pour l’Evaluation de la Qualité de l’Enseignement) and CTI (Commission des Titres d’Ingénieur - France). The present report is dedicated to the evaluation of research led in the Education and Research Department (DER) ArGEnCo. The present evaluation report proposes a global presentation of all our research activities. At the Department level, one of the elected members of the Executive Bureau is in charge of the Research, covering both evaluation and quality policy. In October 2013, the Executive bureau appointed a research steering committee, whose fist task was to coordinate the present evaluation report, following the guidelines of the SMAQ service. The draft of such a document arises from the work of the steering committee but also from the contributions of all Department members, who were asked to contribute to the report or to complete databases. The progress of this evaluation report was presented by the Steering committee to the Department Council and during the General Assembly of the Department. Moreover, two Focus groups were organized by the SMAQ service, in order to get the feedback of technician and administrative members on one hand and scientific members on the other hand, on the general organization of the research in the ArGEnCo Department. The reports of these two Focus groups (Appendix 4 in French) underpinned our thinking about our research management. This report is therefore the fist evaluation of the research led in the Department, the present effort should be pursued, and deepened, within the coming years. Some of the databases necessary for the evaluation have been developed in the frame of this procedure. This has resulted in a huge amount of work for every Department members to collect all the data. New procedures in the management of the Department will help establishing the next research evaluation reports systematically, in particular for the collection of the complete dataset. Following the guidelines of the SMAQ service, this evaluation report is divided into two main parts: the fist one focuses on a self-evaluation report of the research activities and the second part presents the Action Plan of the Department for the next five years to come. The self-evaluation report is composed of four Sections: Section one presents the Research organization and topics of the Department, Section two focuses on the Research activities, Section three gives an overview of the mobility (in and out), the attractiveness and the scientific recognition of the Department and finally Section four is dedicated to the resources available in ArGEnCo Department. Each Section ends up with a SWOT analysis. The Action Plan proposed by the Steering Committee results from the analysis of the self-evaluation report, insofar as it synthesizes and prioritizes the actions of the Department for the next fie years. These priorities are formulated as proposals following a contractual approach between research entities and Institution authorities, to whom the report will be presented. [less ▲]

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See detailAnalytical procedure to derive P-I diagram of a beam under explosion
Hamra, Lotfi ULg; Demonceau, Jean-François ULg; Denoël, Vincent ULg

in Proceeding of the IABSE Workshop - Safety, Robustness and Condition Assessments of Structures (2015, February)

The aim of this paper is to study a beam extracted from a frame and subjected to blast loading. The demand of ductility depends on six dimensionless parameters: two related to the blast loading, two ... [more ▼]

The aim of this paper is to study a beam extracted from a frame and subjected to blast loading. The demand of ductility depends on six dimensionless parameters: two related to the blast loading, two referring to the bending behaviour of the beam and two corresponding to the dynamic behaviour of the rest of the structure. We develop a full analytical procedure that provides the ductility demand as a function of these six dimensionless parameters. [less ▲]

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See detailDevelopment and validation of an accelerometer-based method for quantifying gait events
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Stamatakis, Julien et al

in Medical Engineering & Physics (2015)

An original signal processing algorithm is presented to automatically extract, on a stride-by-stride basis, four consecutive fundamental events of walking, heel strike (HS), toe strike (TS), heel-off (HO ... [more ▼]

An original signal processing algorithm is presented to automatically extract, on a stride-by-stride basis, four consecutive fundamental events of walking, heel strike (HS), toe strike (TS), heel-off (HO), and toe-off (TO), from wireless accelerometers applied to the right and left foot. First, the signals recorded from heel and toe three-axis accelerometers are segmented providing heel and toe flat phases. Then, the four gait events are defined from these flat phases. The accelerometer-based event identification was validated in seven healthy volunteers and a total of 247 trials against reference data provided by a force plate, a kinematic 3D analysis system, and video camera. HS, TS, HO, and TO were detected with a temporal accuracy ± precision of 1.3 ms ± 7.2 ms, ‒4.2 ms ± 10.9 ms, ‒3.7 ms ± 14.5 ms, and ‒1.8 ms ± 11.8 ms, respectively, with the associated 95% confidence intervals ranging from ‒6.3 ms to 2.2 ms. It is concluded that the developed accelerometer-based method can accurately and precisely detect HS, TS, HO, and TO, and could thus be used for the ambulatory monitoring of gait features computed from these events when measured concurrently in both feet. [less ▲]

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See detailConstrained Buckling of a Plane Elastica Inside a Frictional Conduit
Liakou, Anna; Denoël, Vincent ULg; Detournay, Emmanuel

Conference (2015)

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See detailSegmentation of gait cycles using foot-mounted 3D accelerometers
Boutaayamou, Mohamed ULg; Bruls, Olivier ULg; Denoël, Vincent ULg et al

in Proceedings of the IEEE International Conference on 3D Imaging 2015 (2015)

We describe a new gait segmentation method based on the continuous wavelet transform to identify stride-by-stride gait cycles from measurements of foot-mounted three-dimensional (3D) accelerometers. The ... [more ▼]

We describe a new gait segmentation method based on the continuous wavelet transform to identify stride-by-stride gait cycles from measurements of foot-mounted three-dimensional (3D) accelerometers. The detection of such gait cycles is indeed a crucial step for an accurate extraction of relevant gait events such as heel strike, toe strike, heel-off, and toe-off. We demonstrate the ability of this segmentation method, used in conjunction with a validated extraction algorithm, to calculate the following gait (duration) parameters for each gait cycle during the gait of a healthy young subject and of an elderly subject with Parkinson’s disease (PD) in OFF and ON states: durations of (1) loading response, (2) mid-stance, (3) push-off, (4) stance, (5) swing, (6) stride, (7) step, and (8) double support phases. The experimental results show that the proposed method can extract relevant refined gait parameters to quantify subtle gait disturbances in subjects with PD. [less ▲]

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See detailDE3: Yet another high-order integration scheme for linear structural dynamics
Depouhon, Alexandre; Detournay, Emmanuel; Denoël, Vincent ULg

in Proceedings of the 5th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering. (2015)

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See detailResponse of an oscillator to a random quadratic velocity-feedback loading
Denoël, Vincent ULg; Carassale, Luigi

in Journal of Wind Engineering and Industrial Aerodynamics (2015), 147

Abstract The aerodynamic force acting on compact structures is often modeled as a quadratic function of the wind velocity, which fluctuates randomly due to the atmospheric turbulence. When a flexible ... [more ▼]

Abstract The aerodynamic force acting on compact structures is often modeled as a quadratic function of the wind velocity, which fluctuates randomly due to the atmospheric turbulence. When a flexible structure is considered and the quasi-steady assumption is applied, the wind velocity is substituted by the wind-structure relative velocity and, even in case of linear structures, the composite aerodynamic-mechanical system is governed by a nonlinear differential equation characterized by a quadratic feedback term. This class of dynamical systems has been deeply investigated (with different levels of simplifications) applying several alternative mathematical approaches. In this paper we define a system approximation based on a 2nd-order Volterra series and obtain its statistical response in terms of cumulants. The response cumulants are calculated applying the Multiple Timescale Spectral Analysis leading to analytic or semi-analytic expressions. All the approximations are validated through Monte Carlo simulation within a wide parameter space. Then, the analytical structure of the obtained expressions is used to discuss, from a qualitative point of view, the behavior of the considered dynamical system. [less ▲]

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See detailNumerical simulation of percussive drilling
Depouhon, Alexandre; Denoël, Vincent ULg; Detournay, Emmanuel

in International Journal for Numerical and Analytical Methods in Geomechanics (2015), 39(8), 889-912

This paper presents a novel dynamical model to analyze the long-term response of a percussive drilling system. This departs from existing approaches that usually consider a single activation and bit/rock ... [more ▼]

This paper presents a novel dynamical model to analyze the long-term response of a percussive drilling system. This departs from existing approaches that usually consider a single activation and bit/rock interaction cycle for the analysis of the process performance. The proposed model integrates the axial dynamics of an elastic piston and an elastic drill bit, a motion-dependent pressure law to drive the piston, and a generalized bit/rock interaction law representative of the dynamic indentation taking place at the bit/rock interface. It applies to down-the-hole percussive drilling as well as top-hole, with minor modifications. The model does not account for the angular motion or the hole cleaning, however. The model is first formulated mathematically; then, a finite-dimensional approximation is proposed for computations. Numerical analyses of the model response, for a low-size down-the-hole percussive system, follow. The period-1 stationary response for the reference configuration is studied in detail, and parametric analyses assessing the influence on the rate of penetration of the bit/rock interaction parameters, the feed force, and the percussive activation parameters are conducted. These analyses reveal that the multiscale nature of the process is well captured by the model and recover expected trends for the influence of the parameters. They also suggest that a significant increase of the penetration rate can be achieved by increasing the percussive frequency. Copyright © 2015 John Wiley & Sons, Ltd [less ▲]

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See detailAmbulatory system using wearable accelerometers for gait analysis in Parkinson’s disease
Boutaayamou, Mohamed ULg; Demonceau, Marie ULg; Schwartz, Cédric ULg et al

in Proceedings of the 14th Belgian Day on Biomedical Engineering (2015)

We describe a signal-processing algorithm for gait analysis in Parkinson’s disease (PD) using an ambulatory system with wearable accelerometers. This algorithm is versatile enough to detect, on a stride ... [more ▼]

We describe a signal-processing algorithm for gait analysis in Parkinson’s disease (PD) using an ambulatory system with wearable accelerometers. This algorithm is versatile enough to detect, on a stride-by-stride basis, refined gait parameters that quantify subtle gait disturbances in PD in a rater-independent way. [less ▲]

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