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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)

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See detailDamage Diagnosis of Beam-like Structures Based on Sensitivities of Principal Component Analysis Results
Nguyen, Viet Ha ULg; Golinval, Jean-Claude ULg

in IMAC-XXVIII A Conference on Structural Dynamics (2010)

This paper addresses the problem of damage detection and localization in linear-form structures. Principal Component Analysis (PCA) is a popular technique for dynamic system investigation. The aim of the ... [more ▼]

This paper addresses the problem of damage detection and localization in linear-form structures. Principal Component Analysis (PCA) is a popular technique for dynamic system investigation. The aim of the paper is to present a damage diagnosis method based on sensitivities of PCA results in the frequency domain. Starting from Frequency Response Functions (FRFs) measured at different locations on the beam, PCA is performed to determine the main features of the signals. Sensitivities of principal directions obtained from PCA to beam parameters are then computed and inspected according to the location of sensors; their variation from the healthy state to the damaged state indicates damage locations. It is worth noting that damage localization is performed without the need of modal identification. Once the damage has been localized, its evaluation may be quantified if a structural model is available. This evaluation is based on a model updating procedure using previously estimated sensitivities. The efficiency and limitations of the proposed method are illustrated using numerical and experimental examples. [less ▲]

Detailed reference viewed: 83 (26 ULg)
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See detailDamage Localisation Using Principal Component Analysis of Distributed Sensor Array
De Boe, Pascal; Golinval, Jean-Claude ULg

Conference given outside the academic context (2001)

The spatial information given by the distributed sensors (e.g., piezoelectric laminates) can be used to forecast structural damage on localised critical spot. It is well known that a localised structural ... [more ▼]

The spatial information given by the distributed sensors (e.g., piezoelectric laminates) can be used to forecast structural damage on localised critical spot. It is well known that a localised structural damage with relative small amplitude does not affect significantly the modal response of the structure, at least at low frequencies. Nevertheless, a local de-lamination or electrode deterioration at the distributed sensor level will show significant changes on the response of the sensor by modifying its apparent electromechanical coupling. Assuming that the number of sensors is greater than the number of involved structural modes, a local structural damage, with relative small amplitude, will only affect a particular distributed sensor without affecting significantly the response of the others. By applying a principal component analysis (PCA) on the sensor time responses, it is possible to see that any change of one particular sensor electromechanical coupling factor will affect the subspace generated by the complete sensor response set. The subspace generated with the damaged structure can then be compared with the subspace of an initial state in order to diagnose damage or not. [less ▲]

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See detailDamage localization in Linear-Form Structures Based on Sensitivity Investigation for Principal Component Analysis
Nguyen, Viet Ha ULg; Golinval, Jean-Claude ULg

in Journal of Sound & Vibration (2010), 329

This paper addresses the problem of damage detection and localization in linear-form structures. Principal Component Analysis (PCA) is a popular technique for dynamic system investigation. The aim of the ... [more ▼]

This paper addresses the problem of damage detection and localization in linear-form structures. Principal Component Analysis (PCA) is a popular technique for dynamic system investigation. The aim of the paper is to present a damage diagnosis method based on sensitivities of PCA results in the frequency domain. Starting from Frequency Response Functions (FRFs) measured at different locations on the structure; PCA is performed to determine the main features of the signals. Sensitivities of principal directions obtained from PCA to structural parameters are then computed and inspected according to the location of sensors; their variation from the healthy state to the damaged state indicates damage locations. It is worth noting that damage localization is performed without the need of modal identification. Influences of some features as noise, choice of parameter and number of sensors are discussed. The efficiency and limitations of the proposed method are illustrated using numerical and real-world examples. [less ▲]

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See detailDamage mechanics model for the initiation life of stress corrosion cracking
Wu, Ling ULg; Chen, ZhaoTao; Sun, Qin

in Journal of Mechanical Strength = Ji Xie Qiang Du (2004), 26(Suppl.), 58-59

The problem of stress corrosion cracking initiation has been studied on the base of continuum damage mechanics. The attack of load together with environment will weaken the materials, and the degree of ... [more ▼]

The problem of stress corrosion cracking initiation has been studied on the base of continuum damage mechanics. The attack of load together with environment will weaken the materials, and the degree of the weakening can be described well by the damage variable used in damage mechanics.Just as the use of the damage mechanics in predicting the initiation life for creep and fatigue cracks, a stress-corrosion damage evolvement model , which has considered the roles of the threshold stress , effective stress and the existed damage, is established. And the effects of the environment corrosion are presented with the parameters in the evolvement model. Then a stress-corrosion crack initiation life model is deduced from the damage evolvement model with the concept of the damage accumulation. The initiation lives of the stress corrosion cracking have been predicted for two kinds of materials at different stress levels .The predicted results show a good agreement with the testing results. [less ▲]

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See detailA damage model for elastoviscoplastic materials at large strains
Habraken, Anne ULg; Zhu, Y. Y.; Charlier, Robert ULg et al

in Proc. of the Int. Conf. on Computational Plasticity, Fundamentals and Applications, COMPLAS (1995, April)

Detailed reference viewed: 15 (2 ULg)
See detailDamage Model Identification Using Inverse Problem Methodology
KLEINERMANN, J. P.; Ponthot, Jean-Philippe ULg; Stainier, Laurent ULg

in proceedings of Plasticity’2000 (2000)

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See detailDamage modeling of composites and reliability analysis
Zein, Samih; Bruyneel, Michaël ULg

in Proceeding of the ESTEC European Conference on Spacecraft Structures, Materials and Environmental Testing 2014 (2014, April)

Detailed reference viewed: 15 (0 ULg)
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See detailDamage modeling of laminated composites
Nguyen, Ba Nghiep; Fleury, Claude ULg

in Owen, D. R. J.; Onate, E. (Eds.) Computational plasticity: fundamentals and applications: proceedings of the fourth international conference held in Barcelona, Spain, 3rd-6th, April, 1995. Part I (1997)

Detailed reference viewed: 7 (0 ULg)
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See detailDamage modeling of laminated composites : validation of the intra-laminar damage law of SAMCEF at the coupon level for UD plies
Bruyneel, Michaël ULg; Delsemme, Jean-Pierre; Goupil, Anne-Charlotte et al

in proceedings of the European Conference on Composite Material, ECCM16 (2014, June)

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See detailDamage modeling of laminated composites: validation of the inter-laminar damage law of SAMCEF at the coupon level for UD plies
Bruyneel, Michaël ULg; Delsemme, Jean-Pierre; Goupil, Anne-Charlotte et al

in E. Oñate, J. Oliver and A. Huerta (Ed.) Proceedings of the 11th World Congress on Computational Mechanics (WCCM XI) (2014, July)

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See detailDamage modeling of woven-fabric laminates with SAMCEF: validation at the coupon level
Bruyneel, Michaël ULg; Delsemme, Jean-Pierre; Goupil, Anne-Charlotte et al

in Proceedings of the International Conference on Advanced Computational Methods in Engineering – ACOMEN 2014 (2014, June)

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See detailDamage modelling in geotechnics: micromechanical approaches
Levasseur, Séverine ULg; Collin, Frédéric ULg; Charlier, Robert ULg et al

in Zhao, Jian; Labiouse, Vincent; Dudt, Jean-Paul (Eds.) et al EUROCK2010: Rock Mechanics in Civil and Environmental Engineering (2010)

The mechanical behaviours of geomaterials are significantly affected by the presence of voids or cracks-like defects. The modelling of such behaviour is classically performed by considering purely ... [more ▼]

The mechanical behaviours of geomaterials are significantly affected by the presence of voids or cracks-like defects. The modelling of such behaviour is classically performed by considering purely macroscopic or micromechanically-based damage models. In the perspective of applications in civil engineering or in geomechanics, we propose in this paper to evaluate a homogenization approach, based on Mori-Tanaka scheme, applied to microcracked materials. In order to provide an appropriate interpretation of the nonlinear behaviour at macro-scale, the crack-induced damage is coupled to friction phenomena on closed cracks lips. The predictions of the coupled model are first analysed on laboratory tests performed on Callovo-Oxfordian Clay. Then, they are extended to a numerical analysis of excavation damaged zones around tunnels. [less ▲]

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See detailDamage modelling of composites: validation of inter-laminar damage model at the element level
Bruyneel, Michaël ULg; Deslemme, Jean-Pierre; Jetteur, Philippe et al

Article for general public (2014)

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See detailDamage prediction in incremental forming
Guzmán Inostroza, Carlos Felipe ULg

Diverse speeche and writing (2013)

Detailed reference viewed: 12 (5 ULg)
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See detailDamage prediction in single point incremental forming using an extended Gurson model
Guzman, Carlos Felipe; Yuan, Sibo ULg; Duchene, Laurent ULg et al

in International Journal of Solids and Structures (2017)

Single point incremental forming (SPIF) has several advantages over traditional forming, such as the high formability attainable by the material. Different hypotheses have been proposed to explain this ... [more ▼]

Single point incremental forming (SPIF) has several advantages over traditional forming, such as the high formability attainable by the material. Different hypotheses have been proposed to explain this behavior, but there is still no straightforward relation between the particular stress and strain state induced by SPIF and the material degradation leading to localization and fracture. A systematic review of the state of the art about formability and damage in SPIF is presented and an extended Gurson–Tvergaard–Needleman (GTN) model was applied to predict damage in SPIF through finite element (FE) simulations. The line test was used to validate the simulations by comparing force and shape predictions with experimental results. To analyze the failure prediction, several simulations of SPIF cones at different wall angles were performed. It is concluded that the GTN model underestimates the failure angle on SPIF due to wrong coalescence modeling. A physically-based Thomason coalescence criterion was then used leading to an improvement on the results by delaying the onset of coalescence. [less ▲]

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See detailDamage process sensitivity analysis using an XFEM-Level Set framework
Noël, Lise ULg; Duysinx, Pierre ULg; Maute, Kurt

in Proceedings of the 11th World Congress on Structural and Multidisciplinary Optimization (WCSMO-11) (2015, June)

Designing efficient and lightweight structures is a key objective for many industrial applications such as in aerospace or the automotive industry. To this end, composite materials are appealing as they ... [more ▼]

Designing efficient and lightweight structures is a key objective for many industrial applications such as in aerospace or the automotive industry. To this end, composite materials are appealing as they combine high stiffness and light weight. The main challenge slowing down the integration of such materials in real structures is their damage be- havior. The latter should be considered in the design process of the structures. This work focuses on developing a systematic approach to designing structures that can sustain an acceptable amount of degradation or exhibit a low sensitivity to damage. An optimization approach is chosen to achieve this goal. To deal with complex geometries and to allow for large shape modifications in the optimization process, the extended finite element method (XFEM) is advantageously combined with a level set description of geometry. The degradation of materials is modeled by using a non-local damage model, motivated by the work of James and Waisman on a density approach to topol- ogy optimization. To solve design problems with damage constraints by gradient-based optimization method, a sensitivity analysis of the damage process is developed. Damage propagation and growth is an irreversible pro- cess. Therefore, the path dependence of the structural response needs to be accounted for in the sensitivity analysis. In this paper, we present an analytical approach for efficiently and accurately evaluating the design sensitivities, considering both direct and adjoint formulations. Finally, the sensitivity analysis approach is studied with simple benchmark problems and compared with the results obtained by finite differences. [less ▲]

Detailed reference viewed: 104 (19 ULg)
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See detailA damage to crack transition model accounting for stress triaxiality formulated in a hybrid non-local implicit discontinuous Galerkin - cohesive band model framework
Leclerc, Julien ULg; Wu, Ling ULg; Nguyen, Van Dung ULg et al

in International Journal for Numerical Methods in Engineering (in press)

Modelling the entire ductile fracture process remains a challenge. On the one hand, continuous damage models succeed in capturing the initial diffuse damage stage but are not able to represent ... [more ▼]

Modelling the entire ductile fracture process remains a challenge. On the one hand, continuous damage models succeed in capturing the initial diffuse damage stage but are not able to represent discontinuities or cracks. On the other hand, discontinuous methods, as the cohesive zones, which model the crack propagation behaviour, are suited to represent the localised damaging process. However, they are unable to represent diffuse damage. Moreover, most of the cohesive models do not capture triaxiality effect. In this paper, the advantages of the two approaches are combined in a single damage to crack transition framework. In a small deformation setting, a non-local elastic damage model is associated with a cohesive model in a discontinuous Galerkin finite element framework. A cohesive band model is used to naturally introduce a triaxiality-dependent behaviour inside the cohesive law. Practically, a numerical thickness is introduced to recover a 3D-state, mandatory to incorporate the in-plane stretch effects. This thickness is evaluated to ensure the energy consistency of the method and is not a new numerical parameter. The traction-separation law is then built from the underlying damage model. [less ▲]

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See detailA damage/repair model for alveolar bone remodeling
Mengoni, Marlène ULg; Ponthot, Jean-Philippe ULg

in Middleton; Evans; Holt (Eds.) et al 8th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering : CMBBE2008, Porto, Porugal (2008)

Detailed reference viewed: 69 (19 ULg)