Pub Date : 2007-11-01DOI: 10.1080/17747120.2007.9692979
Alberto Patron, C. Crémona
ABSTRACT A probabilistic method for assessing the fatigue damage of welded joints in highway bridges is presented. The proposed method is based on a Markov chain approach. This method provides a better knowledge of damage kinetics in comparison of classical approaches based on the structural reliability concepts. In return, it does not require sophisticated techniques from stochastic calculus for integrating stochastic differential equations. This approach can be easily modified to take into account the influence of nondestructive testing techniques for the evaluation of a joint reliability. The method is applied to the study of a typical stiffener/flange welded joint of a composite bridge.
{"title":"Modèle de chaînes de Markov pour l'étude de la fissuration par fatigue des assemblages soudés de ponts","authors":"Alberto Patron, C. Crémona","doi":"10.1080/17747120.2007.9692979","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692979","url":null,"abstract":"ABSTRACT A probabilistic method for assessing the fatigue damage of welded joints in highway bridges is presented. The proposed method is based on a Markov chain approach. This method provides a better knowledge of damage kinetics in comparison of classical approaches based on the structural reliability concepts. In return, it does not require sophisticated techniques from stochastic calculus for integrating stochastic differential equations. This approach can be easily modified to take into account the influence of nondestructive testing techniques for the evaluation of a joint reliability. The method is applied to the study of a typical stiffener/flange welded joint of a composite bridge.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116265735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-29DOI: 10.1080/17747120.2007.9692986
J. Sanahuja, L. Dormieux, G. Chanvillard
ABSTRACT Concrete is a complex multi-scale composite involving multi-physics processes. As it is the only evolving component, the cement paste has a major influence on the mechanical properties of concrete at early age. The homogenization theory for disordered media is used in order to model the development of the elastic properties of a cement paste during its hydration. The morphological model refers to two types of C-S-H distinguished by many authors: high density C-S-H or inner products build up layers surrounding the anhydrous particles, while low density C-S-H or outer products play the role of a porous matrix. The effective Young's modulus evolution with respect to the degree of hydration proves to be in excellent agreement with the experimental results available in the literature.
{"title":"Modélisation de l'élasticité d'une pâte de ciment au jeune âge","authors":"J. Sanahuja, L. Dormieux, G. Chanvillard","doi":"10.1080/17747120.2007.9692986","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692986","url":null,"abstract":"ABSTRACT Concrete is a complex multi-scale composite involving multi-physics processes. As it is the only evolving component, the cement paste has a major influence on the mechanical properties of concrete at early age. The homogenization theory for disordered media is used in order to model the development of the elastic properties of a cement paste during its hydration. The morphological model refers to two types of C-S-H distinguished by many authors: high density C-S-H or inner products build up layers surrounding the anhydrous particles, while low density C-S-H or outer products play the role of a porous matrix. The effective Young's modulus evolution with respect to the degree of hydration proves to be in excellent agreement with the experimental results available in the literature.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129100516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-01DOI: 10.1080/17747120.2007.9692972
F. Dufour
ABSTRACT For a long time, size effect measured on failure properties of geomaterials have been explained by the randomness of material properties. However, the analysis of scaling law shows that the probabilistic aspect does not introduce an internal length that is necessary to reproduce experimental measurements. This is done with the Bazant's size effect law whose parameters can be deduced from experimental results or from numerical ones using regularized approaches of failure models.
{"title":"Size effect in geomaterials","authors":"F. Dufour","doi":"10.1080/17747120.2007.9692972","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692972","url":null,"abstract":"ABSTRACT For a long time, size effect measured on failure properties of geomaterials have been explained by the randomness of material properties. However, the analysis of scaling law shows that the probabilistic aspect does not introduce an internal length that is necessary to reproduce experimental measurements. This is done with the Bazant's size effect law whose parameters can be deduced from experimental results or from numerical ones using regularized approaches of failure models.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129372273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-01DOI: 10.1080/17747120.2007.9692969
I. Carol, A. Idiart, C. López, A. Caballero
ABSTRACT Interface elements for discrete fracture plus meso-level geometric representation are emerging as a powerful tool for the modeling of the behavior of heterogeneous materials such as concrete. The group of mechanics of materials at ETSECCPB has been developing such tools in which meso-geometry is generated numerically via Voronoi/Delaunay approach, and all lines in the FE mesh are considered as potential crack lines with traction-separation constitutive models based on principles of non-linear fracture mechanics. Results of mechanical analysis turn out very realistic, both mesoscopically (distributed microcrack, coalescence, localization) and macroscopically (average stress-strain curves for specimen). On-going extensions aim at modeling diffusion-driven and coupled phenomena such as drying shrinkage.
{"title":"Multiaxial behavior of concrete","authors":"I. Carol, A. Idiart, C. López, A. Caballero","doi":"10.1080/17747120.2007.9692969","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692969","url":null,"abstract":"ABSTRACT Interface elements for discrete fracture plus meso-level geometric representation are emerging as a powerful tool for the modeling of the behavior of heterogeneous materials such as concrete. The group of mechanics of materials at ETSECCPB has been developing such tools in which meso-geometry is generated numerically via Voronoi/Delaunay approach, and all lines in the FE mesh are considered as potential crack lines with traction-separation constitutive models based on principles of non-linear fracture mechanics. Results of mechanical analysis turn out very realistic, both mesoscopically (distributed microcrack, coalescence, localization) and macroscopically (average stress-strain curves for specimen). On-going extensions aim at modeling diffusion-driven and coupled phenomena such as drying shrinkage.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126991978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-01DOI: 10.1080/17747120.2007.9692973
M. Jirásek
ABSTRACT First it is shown by a simple one-dimensional example that stress-strain laws with softening cannot provide an objective description of response on the structural level. The phenomenon of discontinuous bifurcation from a uniform state is then analyzed in a general threedimensional setting. Localization conditions for isotropic damage models are derived in the general form and then specialized for models with damage driven by equivalent strain dependent on the stored elastic energy, on the maximum principal effective stress, or on the positive part of the strain tensor.
{"title":"Mathematical analysis of strain localization","authors":"M. Jirásek","doi":"10.1080/17747120.2007.9692973","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692973","url":null,"abstract":"ABSTRACT First it is shown by a simple one-dimensional example that stress-strain laws with softening cannot provide an objective description of response on the structural level. The phenomenon of discontinuous bifurcation from a uniform state is then analyzed in a general threedimensional setting. Localization conditions for isotropic damage models are derived in the general form and then specialized for models with damage driven by equivalent strain dependent on the stored elastic energy, on the maximum principal effective stress, or on the positive part of the strain tensor.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123468549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-01DOI: 10.1080/17747120.2007.9692974
M. Jirásek
ABSTRACT This paper starts with an overview of models that can provide an objective description of highly localized inelastic deformation. Basic ideas behind the integral and differential formulations of nonlocal models are explained using a simple isotropic damage model as a typical example. Regularizing effect of nonlocal enhancements is documented by one-dimensional localization analysis. The paper then focuses in detail on integral-type nonlocal damage models. The main issues addressed here include the choice of the internal variable to be averaged, the influence of boundaries, and various computational aspects ranging from efficient implementation of nonlocal averaging to adaptive techniques.
{"title":"Nonlocal damage mechanics","authors":"M. Jirásek","doi":"10.1080/17747120.2007.9692974","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692974","url":null,"abstract":"ABSTRACT This paper starts with an overview of models that can provide an objective description of highly localized inelastic deformation. Basic ideas behind the integral and differential formulations of nonlocal models are explained using a simple isotropic damage model as a typical example. Regularizing effect of nonlocal enhancements is documented by one-dimensional localization analysis. The paper then focuses in detail on integral-type nonlocal damage models. The main issues addressed here include the choice of the internal variable to be averaged, the influence of boundaries, and various computational aspects ranging from efficient implementation of nonlocal averaging to adaptive techniques.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"127 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113967369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-01DOI: 10.1080/17747120.2007.9692968
C. Dascalu
ABSTRACT This contribution introduces the basic concepts of Fracture Mechanics in linear elastic materials. A brief review of the history of Fracture Mechanics is given in the first section of the paper. Then we present the asymptotic behavior of the mechanical fields near the crack fronts. Basic fracture modes and corresponding stress intensity factors are defined. An energy analysis of crack propagation is performed, the energy released rate and the path-independent J integral are introduced. We finally present fracture propagation criteria, for simple or mixed mode loadings.
{"title":"An introduction to fracture mechanics in linear elastic materials","authors":"C. Dascalu","doi":"10.1080/17747120.2007.9692968","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692968","url":null,"abstract":"ABSTRACT This contribution introduces the basic concepts of Fracture Mechanics in linear elastic materials. A brief review of the history of Fracture Mechanics is given in the first section of the paper. Then we present the asymptotic behavior of the mechanical fields near the crack fronts. Basic fracture modes and corresponding stress intensity factors are defined. An energy analysis of crack propagation is performed, the energy released rate and the path-independent J integral are introduced. We finally present fracture propagation criteria, for simple or mixed mode loadings.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126268091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-01DOI: 10.1080/17747120.2007.9692975
A. Simone
ABSTRACT This article provides a brief overview of nonlocal differential damage models. The basic concepts of nonlocal averaging are briefly recalled and used as basis for the derivation of implicit and explicit gradient-enhanced models. Some applications to typical localization problems highlight the merits and demerits of this class of models.
{"title":"Explicit and implicit gradient-enhanced damage models","authors":"A. Simone","doi":"10.1080/17747120.2007.9692975","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692975","url":null,"abstract":"ABSTRACT This article provides a brief overview of nonlocal differential damage models. The basic concepts of nonlocal averaging are briefly recalled and used as basis for the derivation of implicit and explicit gradient-enhanced models. Some applications to typical localization problems highlight the merits and demerits of this class of models.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127865862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-01DOI: 10.1080/17747120.2007.9692976
A. Simone
ABSTRACT In this paper we review some basic notions of partition of unity-based discontinuous finite elements showing their relation to the Generalized Finite Element Method. A minimal one-dimensional example illustrates some of the issues related to the computer implementation of the method and highlights the relative simplicity of the approach. The ability of the approach in describing displacement discontinuities independently of the finite element mesh is shown in a classical crack propagation problem in an elastic medium. We also illustrate some limitations of this method when used in conjunction with the dummy stiffness approach.
{"title":"Partition of unity-based discontinuous finite elements: GFEM, PUFEM, XFEM","authors":"A. Simone","doi":"10.1080/17747120.2007.9692976","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692976","url":null,"abstract":"ABSTRACT In this paper we review some basic notions of partition of unity-based discontinuous finite elements showing their relation to the Generalized Finite Element Method. A minimal one-dimensional example illustrates some of the issues related to the computer implementation of the method and highlights the relative simplicity of the approach. The ability of the approach in describing displacement discontinuities independently of the finite element mesh is shown in a classical crack propagation problem in an elastic medium. We also illustrate some limitations of this method when used in conjunction with the dummy stiffness approach.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124740837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-08-01DOI: 10.1080/17747120.2007.9692967
M. Jirásek
ABSTRACT This paper provides a brief overview of the basic concepts and equations that will be used by other papers in the special issue on Damage and Fracture in Geomaterials. The first section introduces the tensorial notation, defines the basic tensor operations and presents the formalism for the volumetric-deviatoric decomposition of stress and strain. The second section shows how to transcribe tensorial relations in the engineering notation. The basic equations describing a linear elastic deformable body are summarized in the third section, and their discretization by the finite element method is described in the fourth section, with an extension to nonlinear constitutive relations in the fifth section. The last section outlines a thermodynamic framework based on two potentials—the free energy and the dissipation potential.
{"title":"Basic concepts and equations of solid mechanics","authors":"M. Jirásek","doi":"10.1080/17747120.2007.9692967","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692967","url":null,"abstract":"ABSTRACT This paper provides a brief overview of the basic concepts and equations that will be used by other papers in the special issue on Damage and Fracture in Geomaterials. The first section introduces the tensorial notation, defines the basic tensor operations and presents the formalism for the volumetric-deviatoric decomposition of stress and strain. The second section shows how to transcribe tensorial relations in the engineering notation. The basic equations describing a linear elastic deformable body are summarized in the third section, and their discretization by the finite element method is described in the fourth section, with an extension to nonlinear constitutive relations in the fifth section. The last section outlines a thermodynamic framework based on two potentials—the free energy and the dissipation potential.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123490893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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