Stéphane Andrieux - Academia.edu (original) (raw)
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Papers by Stéphane Andrieux
HAL (Le Centre pour la Communication Scientifique Directe), Dec 23, 2016
Nuclear Engineering and Design, Sep 1, 1995
WIT transactions on engineering sciences, 1970
The purpose of the paper is to construct, by means of an homogenization process, thermoelastic da... more The purpose of the paper is to construct, by means of an homogenization process, thermoelastic damaging constitutive laws including the effects of thermal gradients Unlike usual models, a dependence of the macroscopic free energy on the thermal gradients vector is obtained. A careful derivation of the macroscopic form of the Clausius-Duhem inequality remove the apparent contradiction with general results of Coleman and Gurtin denying any dependence of the free energy on thermal gradient Applications have been made for micro cracked media, the energy release rate actually depends on the thermal gradients and the damage yield function is then supplemented by a quadratic term. Numerical validations of the model, by direct computation of a large periodic structure under thermal loading show very good agreement with theoretical results.
International Journal of Plasticity, Mar 1, 1999
To control localization phenomena exhibited by strain softening constitutive relations, several i... more To control localization phenomena exhibited by strain softening constitutive relations, several issues have been proposed by various authors, based on spatial regularization. In this paper, we de®ne a variational framework, thought to encompass some of these issues: the constitutive relations are written at the structural scale and become minimization problems. Such a framework is not only well-suited to the mathematical study of the boundary value problem, but also leads in a natural way to an ecient numerical algorithm. The formulation is ®rst presented, then applied to several classes of models existing in the literature : a homogenization-based constitutive relation, a porosity model and gradient plasticity. Besides the higher degree of generality confered by the formulation, it will be shown that several properties can be obtained for these models.
HAL (Le Centre pour la Communication Scientifique Directe), May 21, 2007
Comptes rendus, Feb 1, 2023
Bregman divergences for physically informed discrepancy measures for learning and computation in ... more Bregman divergences for physically informed discrepancy measures for learning and computation in thermomechanics
HAL (Le Centre pour la Communication Scientifique Directe), 2007
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), May 28, 2006
Springer eBooks, 1991
The extension to 3D situations of an uniaxial cyclic constituive law with a discrete memory varia... more The extension to 3D situations of an uniaxial cyclic constituive law with a discrete memory variable is presented. Attention is focused on the precise definition of the extended 3D corresponding variables. The discrete nature of the memory leads to discontinuity problems for some loading paths, a modification is then proposed which uses a differential evolution law. For large enough uniaxial cycles, the uniaxial law is nevertheless recovered. Lastly, an incremental form of the implicit evolution problem is given.
HAL (Le Centre pour la Communication Scientifique Directe), Dec 23, 2016
Testing in Aerospace Research procedures for the simulation means. Table 1 illustrates some of th... more Testing in Aerospace Research procedures for the simulation means. Table 1 illustrates some of the mutual benefits that experiments, simulation and inverse problems have gained by collaborating. In this paper, a partial overview will be given of some techniques and results emanating from the signal processing theory and the inverse problem community, which have enhanced, made possible or increased the performance level of experiments. Emphasis will also be placed on the notion of a priori information in inverse problems, this information being extracted from all of the knowledge accumulated through experiments. First, linear problems arising essentially from signal processing are addressed. Then, two problems coping with image capturing are investigated, since they are considered to be of utmost importance in aeronautical applications: the first deals with Particle Image Velocimetry for fluid flows, and the second one deals with full-field displacement measurement by digital image correlation in mechanics.
HAL (Le Centre pour la Communication Scientifique Directe), Jun 30, 2008
Journal of Sound and Vibration, 2007
In this paper, a modal approach to fracture mechanics for dynamic loading is proposed. This appro... more In this paper, a modal approach to fracture mechanics for dynamic loading is proposed. This approach is based on the linear recombination of modal stress intensity factors. The modal stress intensity factors may be computed either from a classical crack-tip-opening-displacement method or by an energy method that is detailed in this paper. The energy method is based on a bilinear form stemming from the energy release rate quadratic form and it turns out to be very satisfactorycompared to other methods-in a large range of frequencies, up to moderate frequencies. The accuracy of the modal approach to fracture mechanics is discussed through several examples and demonstrated in an industrial application.
Le Journal de Physique IV, 1996
the aim of this work is to include the metallurgical behaviour of steels (and specifically their ... more the aim of this work is to include the metallurgical behaviour of steels (and specifically their phase transformations) irrto thermo-mechanical studies. In this purpose, a new model of anisothermal phase transfomations during the cooling stage is proposed. Developed in the thermodynamics framework of simple materials with memory variables, its originality lies in the choice of the temperature time derivativeT as an independent variable. The identification and the transformation rates computation use the CCT diagrams which are considered as families of particular solutions of evolution equations. The validation shows ability of the model to simulate all CCT deductible tests. Furthermore, for some tests not included into the CCT the numerical results remain good and the model, from which evolution equation form as been let free, allows to incorporate them to the identification data without modifying the CCT simulation accuracy. Lastly, for all the previous tests, this model has been compared with the one of the Sysweld software.
Le Journal de Physique IV, 1996
A general framework for deriving and using a class of constitutive laws incorporating spatial gra... more A general framework for deriving and using a class of constitutive laws incorporating spatial gradients of internal variables is presented. It user two basic ingredients : a derivation of such models by homogenization techniques and a reformulation of the et~olution eyuation at the scale of the whole structure.
R F M Revue Francaise De Mecanique, 2000
Une methode originale de calcul de la loi de comportement en flexion d'une section de poutre ... more Une methode originale de calcul de la loi de comportement en flexion d'une section de poutre fissuree est proposee dans cet article. L'objectif est de definir, a partir de calculs tridimensionnels tenant compte du contact unilateral entre les levres de la fissure, une relation de comportement (non lineaire) entre le torseur d'efforts applique et le champ de deplacements resultant, qui soit compatible avec la theorie des poutres afin d'en permettre l'introduction dans un modele filaire, L'application de cette methode au cas d'une section comportant une fissure a fond droit de 50 % est presentee.
Inverse Problems in Engineering Mechanics; Intl. Union of Theoretical and Applied Mechanics (IUTAM) Symposium, 1993
A number of inverse or identification problems in engineering mechanics are severly ill-posed whe... more A number of inverse or identification problems in engineering mechanics are severly ill-posed when formulated in the initial three-dimensional framework. We propose to show in this paper how, for thin or moderately thin domains, the alternative approach of the problem via shell theories can give rise to some progess both from the theoretical and practical points of view and lead
HAL (Le Centre pour la Communication Scientifique Directe), Dec 23, 2016
Nuclear Engineering and Design, Sep 1, 1995
WIT transactions on engineering sciences, 1970
The purpose of the paper is to construct, by means of an homogenization process, thermoelastic da... more The purpose of the paper is to construct, by means of an homogenization process, thermoelastic damaging constitutive laws including the effects of thermal gradients Unlike usual models, a dependence of the macroscopic free energy on the thermal gradients vector is obtained. A careful derivation of the macroscopic form of the Clausius-Duhem inequality remove the apparent contradiction with general results of Coleman and Gurtin denying any dependence of the free energy on thermal gradient Applications have been made for micro cracked media, the energy release rate actually depends on the thermal gradients and the damage yield function is then supplemented by a quadratic term. Numerical validations of the model, by direct computation of a large periodic structure under thermal loading show very good agreement with theoretical results.
International Journal of Plasticity, Mar 1, 1999
To control localization phenomena exhibited by strain softening constitutive relations, several i... more To control localization phenomena exhibited by strain softening constitutive relations, several issues have been proposed by various authors, based on spatial regularization. In this paper, we de®ne a variational framework, thought to encompass some of these issues: the constitutive relations are written at the structural scale and become minimization problems. Such a framework is not only well-suited to the mathematical study of the boundary value problem, but also leads in a natural way to an ecient numerical algorithm. The formulation is ®rst presented, then applied to several classes of models existing in the literature : a homogenization-based constitutive relation, a porosity model and gradient plasticity. Besides the higher degree of generality confered by the formulation, it will be shown that several properties can be obtained for these models.
HAL (Le Centre pour la Communication Scientifique Directe), May 21, 2007
Comptes rendus, Feb 1, 2023
Bregman divergences for physically informed discrepancy measures for learning and computation in ... more Bregman divergences for physically informed discrepancy measures for learning and computation in thermomechanics
HAL (Le Centre pour la Communication Scientifique Directe), 2007
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), May 28, 2006
Springer eBooks, 1991
The extension to 3D situations of an uniaxial cyclic constituive law with a discrete memory varia... more The extension to 3D situations of an uniaxial cyclic constituive law with a discrete memory variable is presented. Attention is focused on the precise definition of the extended 3D corresponding variables. The discrete nature of the memory leads to discontinuity problems for some loading paths, a modification is then proposed which uses a differential evolution law. For large enough uniaxial cycles, the uniaxial law is nevertheless recovered. Lastly, an incremental form of the implicit evolution problem is given.
HAL (Le Centre pour la Communication Scientifique Directe), Dec 23, 2016
Testing in Aerospace Research procedures for the simulation means. Table 1 illustrates some of th... more Testing in Aerospace Research procedures for the simulation means. Table 1 illustrates some of the mutual benefits that experiments, simulation and inverse problems have gained by collaborating. In this paper, a partial overview will be given of some techniques and results emanating from the signal processing theory and the inverse problem community, which have enhanced, made possible or increased the performance level of experiments. Emphasis will also be placed on the notion of a priori information in inverse problems, this information being extracted from all of the knowledge accumulated through experiments. First, linear problems arising essentially from signal processing are addressed. Then, two problems coping with image capturing are investigated, since they are considered to be of utmost importance in aeronautical applications: the first deals with Particle Image Velocimetry for fluid flows, and the second one deals with full-field displacement measurement by digital image correlation in mechanics.
HAL (Le Centre pour la Communication Scientifique Directe), Jun 30, 2008
Journal of Sound and Vibration, 2007
In this paper, a modal approach to fracture mechanics for dynamic loading is proposed. This appro... more In this paper, a modal approach to fracture mechanics for dynamic loading is proposed. This approach is based on the linear recombination of modal stress intensity factors. The modal stress intensity factors may be computed either from a classical crack-tip-opening-displacement method or by an energy method that is detailed in this paper. The energy method is based on a bilinear form stemming from the energy release rate quadratic form and it turns out to be very satisfactorycompared to other methods-in a large range of frequencies, up to moderate frequencies. The accuracy of the modal approach to fracture mechanics is discussed through several examples and demonstrated in an industrial application.
Le Journal de Physique IV, 1996
the aim of this work is to include the metallurgical behaviour of steels (and specifically their ... more the aim of this work is to include the metallurgical behaviour of steels (and specifically their phase transformations) irrto thermo-mechanical studies. In this purpose, a new model of anisothermal phase transfomations during the cooling stage is proposed. Developed in the thermodynamics framework of simple materials with memory variables, its originality lies in the choice of the temperature time derivativeT as an independent variable. The identification and the transformation rates computation use the CCT diagrams which are considered as families of particular solutions of evolution equations. The validation shows ability of the model to simulate all CCT deductible tests. Furthermore, for some tests not included into the CCT the numerical results remain good and the model, from which evolution equation form as been let free, allows to incorporate them to the identification data without modifying the CCT simulation accuracy. Lastly, for all the previous tests, this model has been compared with the one of the Sysweld software.
Le Journal de Physique IV, 1996
A general framework for deriving and using a class of constitutive laws incorporating spatial gra... more A general framework for deriving and using a class of constitutive laws incorporating spatial gradients of internal variables is presented. It user two basic ingredients : a derivation of such models by homogenization techniques and a reformulation of the et~olution eyuation at the scale of the whole structure.
R F M Revue Francaise De Mecanique, 2000
Une methode originale de calcul de la loi de comportement en flexion d'une section de poutre ... more Une methode originale de calcul de la loi de comportement en flexion d'une section de poutre fissuree est proposee dans cet article. L'objectif est de definir, a partir de calculs tridimensionnels tenant compte du contact unilateral entre les levres de la fissure, une relation de comportement (non lineaire) entre le torseur d'efforts applique et le champ de deplacements resultant, qui soit compatible avec la theorie des poutres afin d'en permettre l'introduction dans un modele filaire, L'application de cette methode au cas d'une section comportant une fissure a fond droit de 50 % est presentee.
Inverse Problems in Engineering Mechanics; Intl. Union of Theoretical and Applied Mechanics (IUTAM) Symposium, 1993
A number of inverse or identification problems in engineering mechanics are severly ill-posed whe... more A number of inverse or identification problems in engineering mechanics are severly ill-posed when formulated in the initial three-dimensional framework. We propose to show in this paper how, for thin or moderately thin domains, the alternative approach of the problem via shell theories can give rise to some progess both from the theoretical and practical points of view and lead