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Peer Reviewed
See detailDam treatment with insulin-like growth factor-I monoclonal antibodies induce an alteration of fetal development
Renaville, Robert ULg; Devolder, Anne; Sneyers, Myriam et al

in Archives Internationales de Physiologie, de Biochimie et de Biophysique (1992), 100

Detailed reference viewed: 5 (0 ULg)
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See detailDam-break flow computation based on an efficient flux-vector splitting
Erpicum, Sébastien ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Journal of Computational & Applied Mathematics (2010), 234

Dam-break flow computation is a task of prime interest in the scope of risk analysis processes related to dams and reservoirs. In this paper, a 2D finite volume multiblock flow solver, able to deal with ... [more ▼]

Dam-break flow computation is a task of prime interest in the scope of risk analysis processes related to dams and reservoirs. In this paper, a 2D finite volume multiblock flow solver, able to deal with natural topography variation, is presented in details. The model is based on an efficient Flux Vector Splitting method developed by the authors. A number of validation examples are comprehensively described. [less ▲]

Detailed reference viewed: 159 (57 ULg)
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See detailDam-break flow computation using high resolution DEM
Dewals, Benjamin ULg

Conference (2008, May 26)

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See detailDam-break flow computation using high resolution DEM
Erpicum, Sébastien ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Hogge, Michel; Van Keer, R.; Noels, L. (Eds.) et al Proceedings of the 4th International Conference on Advanced Computational Methods in Engineering (2008)

Dam-break flow computation is a task of prime interest in the scope of risk analysis processes related to dams and reservoirs. High resolution Digital Elevation Models (DEMs) available today provide ... [more ▼]

Dam-break flow computation is a task of prime interest in the scope of risk analysis processes related to dams and reservoirs. High resolution Digital Elevation Models (DEMs) available today provide extremely dense and accurate topography information in the valley downstream of these structures, even in urban area. In this paper, a 2D finite volume flow solver, able to deal with these DEMs, is presented in details. Validation examples are comprehensively described. [less ▲]

Detailed reference viewed: 66 (7 ULg)
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See detailDam-break flow numerical modeling considering structural impacts on buildings
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Proc. 33rd IAHR Congress: Water Engineering for a Sustainable Environment (2009)

Detailed reference viewed: 13 (2 ULg)
See detailDamage and fracture of ductile materials submitted to high strain rates. An implicit thermomechanically coupled approach with element erosion
Jeunechamps, Pierre-Paul ULg; Ponthot, Jean-Philippe ULg

in Proceedings of “PACAM XI, 11th Pan-American Congress of Applied Mechanics (2009)

Detailed reference viewed: 22 (0 ULg)
See detailDamage and fracture of materials submitted to high strain rates. A thermomechanically coupled approach with element erosion
Jeunechamps, Pierre-Paul ULg; Ponthot, Jean-Philippe ULg

in Proceedings of “Dynamic behaviour of materials”, Workshop in memory of Prof. J.R. Klepaczko (2009)

Detailed reference viewed: 11 (1 ULg)
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See detailDamage and Fracture of Materials Submitted to High Strain Rates. A Thermomechanically Implicit Coupled Approach with Element Erosion
Jeunechamps, Pierre-Paul; Boman, Romain ULg; Papeleux, Luc ULg et al

in Proceedings of the 3rd International Conference on Impact Loading of Lightweight Structures (2011, June 28)

Detailed reference viewed: 18 (8 ULg)
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See detailDamage and functional recovery of the Atlantic cod (Gadus morhua) inner ear hair cells following local injection of gentamicin
Faucher, Karine ULg; Aas-Hansen, Øyvind; Damsgård, Borge et al

in International Journal of Audiology (2009), 48(7), 456-464

This study addresses the ultrastructural and functional damage and subsequent recovery of the inner ear in the Atlantic cod following intrasaccular gentamicin injection. Inner ear damage was assessed ... [more ▼]

This study addresses the ultrastructural and functional damage and subsequent recovery of the inner ear in the Atlantic cod following intrasaccular gentamicin injection. Inner ear damage was assessed using SEM and measurements of AEP following 250-Hz pure-tone stimuli. Data from gentamicin-treated fish were compared with control (no injection) and sham (injection of saline) fish. Control fish had normal response thresholds associated with welldeveloped hair cell bundles in their macula sacculi. Sham fish had higher response thresholds compared with control fish during the first week post-intervention, but response thresholds were subsequently normal. Treated fish displayed significant inner ear damage associated with an increased average AEP threshold on the third day following treatment. Thereafter, inner ear tissue displayed signs of progressive regeneration until it was comparable to controls from the 14th day. Response thresholds were similar to those of control fish from the 17th day following treatment. These observations suggest that the macula sacculi of Atlantic cod can regenerate towards a near-complete functional and ultrastructural recovery within 17-21 days following ototoxic gentamicin treatment. [less ▲]

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See detailDamage around tunnels in indurated clay: hydro-mechanical modelling aspects
Levasseur, Séverine ULg; Charlier, Robert ULg; Frieg, Bernd et al

in Li, Xiangling; Jing, Lanru; Blaser, Petra (Eds.) Impact of Thermo-Hydro-Mechanical-Chemical (THMC) processes on the safety of underground radioactive waste repositories (2009, September)

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See detailA damage constitutive law for steel elevated temperature. Identification of the parameters
Castagne, Sylvie; Talamona, D.; Habraken, Anne ULg

in International Journal of Material Processing (2007), (1), 23-43

This paper presents a methodology of damage analysis at elevated temperature using the finite element method. Both the model and the methodology to identify parameters are summarized. The mechanical ... [more ▼]

This paper presents a methodology of damage analysis at elevated temperature using the finite element method. Both the model and the methodology to identify parameters are summarized. The mechanical properties are established using compression tests at elevated temperature. An elasto-visco-plastic model depending on temperature is identified. A metallographic analysis is used to determine the original size and morphology of the austenitic grains. The experimental damage analyses consist in acoustic tests in order to determine the apparition of the first crack during compression. Finite element simulations of these experiments allow the determination of the damage parameters using a reverse method. [less ▲]

Detailed reference viewed: 56 (8 ULg)
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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: 46 (12 ULg)
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See detailDamage Detection in Civil Engineering Structure Considering Temperature Effect
Nguyen, Viet Ha; Mahowald, Jean; Maas, Stefan et al

in Proceedings of IMAC XXXII Dynamics of Coupled Structures (2014, February)

This paper concerns damage identification of a bridge located in Luxembourg. Vibration responses were captured from measurable and adjustable harmonic swept sine excitation and hammer impact. Different ... [more ▼]

This paper concerns damage identification of a bridge located in Luxembourg. Vibration responses were captured from measurable and adjustable harmonic swept sine excitation and hammer impact. Different analysis methods were applied to the data measured from the structure showing interesting results. However, some difficulties arise, especially due to environmental influences (temperature and soil-behaviour variations) which overlay the structural changes caused by damage. These environmental effects are investigated in detail in this work. First, the modal parameters are identified from the response data. In the next step, they are statistically collected and processed through Principal Component Analysis (PCA) and Kernel PCA. Damage indexes are based on outlier analysis. [less ▲]

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See detailDamage detection in composites by vibrothermography and local resonances
Demy, Philippe ULg; Golinval, Jean-Claude ULg; Simon, Daniel

in Mechanics & Industry (2013), 14(2), 137-143

Vibrothermography is an active thermographic technique able to detect singularities like delamination in composite materials. Carbon fibre laminates are increasingly used, especially in aviation industry ... [more ▼]

Vibrothermography is an active thermographic technique able to detect singularities like delamination in composite materials. Carbon fibre laminates are increasingly used, especially in aviation industry where defect detection is directly related to safety. Physical causes of the internal heating mechanism linked to defect interaction with the elastic waves may be friction, viscoelastic hysteresis or plasticity. The method can efficiently detect flaws on complex geometries and only requires that both internal faces or edges are free to vibrate. The purpose of this work is to determine the relation between the observed heating right above a delamination by an IR camera and the frequency of a sinusoidal excitation between 8 and 27 kHz. The results clearly show specific heating peaks at certain frequencies. The comparison with local resonance frequencies of the delamination computed by simplified FEM shows similarities with the appearance of heating peaks. An experimental study having as goal to exploit the presence of those peaks and thus to increase the sensitivity of the method shows the interest for a high sweep sinusoidal excitation of the chirp type. The final objective of this research is to set up a serviceable short and reliable vibrothermographic test for non-destructive testing of composite materials. [less ▲]

Detailed reference viewed: 41 (6 ULg)
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See detailDamage Detection of Mechanical Components Using Null Subspace Analysis
Rutten, Christophe ULg; Loffet, Christophe; Golinval, Jean-Claude ULg

Conference given outside the academic context (2009)

This paper presents two original applications of the Null Subspace Analysis (NSA) method for fault diagnosis in mechanical components. The method is first applied to the case-study of electro-mechanical ... [more ▼]

This paper presents two original applications of the Null Subspace Analysis (NSA) method for fault diagnosis in mechanical components. The method is first applied to the case-study of electro-mechanical devices at the end of the assembly line with the aim of assessing their overall quality. The advantages of the proposed method rely in its rapidity of use and its reliability. At first, a set of five good (i.e. healthy) devices and four damaged devices was considered. The components were instrumented with one triaxial accelerometer on the flank and one monoaxial accelerometer on the top. Based on the NSA method, a mapping of the space [ active components, system order ] up to a system order of 100, was realized in order to select the appropriate order and number of active components. Eventually, thanks to this mapping, the method was able to successfully detect all the faulty components using the signal from only one accelerometer in one direction. The second application is related to the quality assessment of welded joints between stripes in a steel processing plan. Six welded joints with nominal welding parameters and twenty-seven welded joints with out-of-range parameters were realized. Again, the NSA method was able to diagnose successfully the welded joints using a single signal from one accelerometer. [less ▲]

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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: 49 (8 ULg)
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See detailDamage Detection Using Blind Source Separation Techniques
Nguyen, Viet Ha ULg; Golinval, Jean-Claude ULg

in IMAC-XXIX: Conference & Exposition on Structural Dynamics - Advanced Aerospace Applications (2011)

Blind source separation (BSS) techniques are applied in many domains since they allow separating a set of signals from their observed mixture without the knowledge (or with very little knowledge) of the ... [more ▼]

Blind source separation (BSS) techniques are applied in many domains since they allow separating a set of signals from their observed mixture without the knowledge (or with very little knowledge) of the source signals or the mixing process. Two particular BSS techniques called Second-Order Blind Identification (SOBI) and Blind Modal Identification (BMID) are considered in this paper for the purpose of structural damage detection or fault diagnosis in mechanical systems. As shown on experimental examples, the BMID method reveals significant advantages. In addition, it is demonstrated that damage detection results may be improved significantly with the help of the block Hankel matrix. The main advantage in this case is that damage detection still remains possible when the number of available sensors is small or even reduced to one. Damage detection is achieved by comparing the subspaces between the reference (healthy) state and a current state through the concept of subspace angle. The efficiency of the methods is illustrated using experimental data. [less ▲]

Detailed reference viewed: 135 (4 ULg)
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See detailDamage Detection Using Model Updating and Identification Techniques
Pascual, Rodrigo; Trendafilova, Irina; Golinval, Jean-Claude ULg et al

Conference given outside the academic context (1999)

Detailed reference viewed: 9 (0 ULg)