The Experts below are selected from a list of 4020 Experts worldwide ranked by ideXlab platform
Giang D Nguyen - One of the best experts on this subject based on the ideXlab platform.
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a thermodynamics and mechanism based framework for constitutive models with evolving thickness of Localisation Band
International Journal of Solids and Structures, 2020Co-Authors: Giang D Nguyen, Ha H BuiAbstract:Abstract Localised failure in geomaterials invalidates the assumption of homogeneous deformation that constitutive models based on continuum mechanics rest on. In such cases, the deformation and nonlinear processes inside the Localisation zone dominate the inelastic response of the material, while the material outside this zone usually undergoes negligible inelastic or even elastic deformation. As a consequence, internal variables representing micromechanical failure processes should better be defined inside the Localisation zone, not averaged over the whole volume element containing it. In this study, we propose a thermodynamics-based framework for constitutive models that take into account the transition from homogenous to localised deformation. Two spatial scales involved in the mechanisms of localised failure, macro scale of the considered volume element and smaller scale of the Localisation zone, are included in the formulation and derived constitutive models. This separation of spatial scales is combined with enrichments of the constitutive kinematics for the integration of three constitutive relationships describing the behaviour of the materials inside and outside the Localisation zone, and the evolving size of this zone. As a result, the internal variables are associated with their own spatial zones, instead of being averaged over the whole volume element like in classical continuum approaches. The gradual transition from homogenous to localised deformation is represented by the onset and evolution of the thickness of the Localisation Band, both of which appear naturally in the proposed formulation. The obtained model therefore consists of both size and orientation of the Localisation Band, and three constitutive relationships connected through the equilibrium condition across the boundary of the Localisation zone. They help provide a smooth transition from homogeneous to localised failure. Numerical examples show promising features of the proposed approach in connecting the macro behaviour with the underlying evolution of the Localisation zone.
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A size-dependent constitutive modelling framework for localised failure analysis
Computational Mechanics, 2016Co-Authors: Giang D Nguyen, Ha H Bui, Chi T. Nguyen, Vinh P. Nguyen, Luming ShenAbstract:Localised deformation of materials usually takes place in thin Bands during the nonlinear phase of the deformation process. The orientation and size of these Localisation Bands are important properties characterising the post-Localisation behaviour of the materials, and hence should be taken into account in constitutive modelling. In this research, a new approach is proposed for the integration of both size and orientation of a Localisation Band in the constitutive description beyond the onset of Localisation. Since a length scale related to the size of the Localisation Band appears in the model description, its post-Localisation response then scales with both the Band size and the size of the volume element containing it. Therefore, size effects are intrinsically included and post-Localisation behaviour is correctly captured, which helps ensure convergence of numerical solutions upon discretisation refinement in numerical analysis of boundary value problems. The concept together with implementation features of the framework and its performances at constitutive level and in the analysis of boundary value problems are presented in this paper.
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a constitutive modelling framework featuring two scales of behaviour fundamentals and applications to quasi brittle failure
Engineering Fracture Mechanics, 2014Co-Authors: Giang D Nguyen, Alexander M Korsunsky, Itai EinavAbstract:Abstract We propose a constitutive modelling framework with enhanced kinematics to capture localised mode of deformation. The total strain is decomposed into two components to reflect an inelastic Localisation Band embedded in an elastic bulk. This is the usual case in numerical analysis of localised failure in geomaterials, when the size of the Localisation Band is very small compared to an element of the discretised domain under consideration. The proposed framework takes into account the sizes and corresponding behaviours of the two inelastic and elastic zones and hence gives derived constitutive models a length scale. This is an essential feature in dealing with size effect issues as a consequence of localised failure in geomaterials. The proposed framework is applied to a constitutive model for the failure analysis of quasi-brittle materials. The implementation algorithms are developed and novel features are illustrated through numerical examples.
Ha H Bui - One of the best experts on this subject based on the ideXlab platform.
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a thermodynamics and mechanism based framework for constitutive models with evolving thickness of Localisation Band
International Journal of Solids and Structures, 2020Co-Authors: Giang D Nguyen, Ha H BuiAbstract:Abstract Localised failure in geomaterials invalidates the assumption of homogeneous deformation that constitutive models based on continuum mechanics rest on. In such cases, the deformation and nonlinear processes inside the Localisation zone dominate the inelastic response of the material, while the material outside this zone usually undergoes negligible inelastic or even elastic deformation. As a consequence, internal variables representing micromechanical failure processes should better be defined inside the Localisation zone, not averaged over the whole volume element containing it. In this study, we propose a thermodynamics-based framework for constitutive models that take into account the transition from homogenous to localised deformation. Two spatial scales involved in the mechanisms of localised failure, macro scale of the considered volume element and smaller scale of the Localisation zone, are included in the formulation and derived constitutive models. This separation of spatial scales is combined with enrichments of the constitutive kinematics for the integration of three constitutive relationships describing the behaviour of the materials inside and outside the Localisation zone, and the evolving size of this zone. As a result, the internal variables are associated with their own spatial zones, instead of being averaged over the whole volume element like in classical continuum approaches. The gradual transition from homogenous to localised deformation is represented by the onset and evolution of the thickness of the Localisation Band, both of which appear naturally in the proposed formulation. The obtained model therefore consists of both size and orientation of the Localisation Band, and three constitutive relationships connected through the equilibrium condition across the boundary of the Localisation zone. They help provide a smooth transition from homogeneous to localised failure. Numerical examples show promising features of the proposed approach in connecting the macro behaviour with the underlying evolution of the Localisation zone.
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A size-dependent constitutive modelling framework for localised failure analysis
Computational Mechanics, 2016Co-Authors: Giang D Nguyen, Ha H Bui, Chi T. Nguyen, Vinh P. Nguyen, Luming ShenAbstract:Localised deformation of materials usually takes place in thin Bands during the nonlinear phase of the deformation process. The orientation and size of these Localisation Bands are important properties characterising the post-Localisation behaviour of the materials, and hence should be taken into account in constitutive modelling. In this research, a new approach is proposed for the integration of both size and orientation of a Localisation Band in the constitutive description beyond the onset of Localisation. Since a length scale related to the size of the Localisation Band appears in the model description, its post-Localisation response then scales with both the Band size and the size of the volume element containing it. Therefore, size effects are intrinsically included and post-Localisation behaviour is correctly captured, which helps ensure convergence of numerical solutions upon discretisation refinement in numerical analysis of boundary value problems. The concept together with implementation features of the framework and its performances at constitutive level and in the analysis of boundary value problems are presented in this paper.
Luming Shen - One of the best experts on this subject based on the ideXlab platform.
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A size-dependent constitutive modelling framework for localised failure analysis
Computational Mechanics, 2016Co-Authors: Giang D Nguyen, Ha H Bui, Chi T. Nguyen, Vinh P. Nguyen, Luming ShenAbstract:Localised deformation of materials usually takes place in thin Bands during the nonlinear phase of the deformation process. The orientation and size of these Localisation Bands are important properties characterising the post-Localisation behaviour of the materials, and hence should be taken into account in constitutive modelling. In this research, a new approach is proposed for the integration of both size and orientation of a Localisation Band in the constitutive description beyond the onset of Localisation. Since a length scale related to the size of the Localisation Band appears in the model description, its post-Localisation response then scales with both the Band size and the size of the volume element containing it. Therefore, size effects are intrinsically included and post-Localisation behaviour is correctly captured, which helps ensure convergence of numerical solutions upon discretisation refinement in numerical analysis of boundary value problems. The concept together with implementation features of the framework and its performances at constitutive level and in the analysis of boundary value problems are presented in this paper.
Chi T. Nguyen - One of the best experts on this subject based on the ideXlab platform.
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A size-dependent constitutive modelling framework for localised failure analysis
Computational Mechanics, 2016Co-Authors: Giang D Nguyen, Ha H Bui, Chi T. Nguyen, Vinh P. Nguyen, Luming ShenAbstract:Localised deformation of materials usually takes place in thin Bands during the nonlinear phase of the deformation process. The orientation and size of these Localisation Bands are important properties characterising the post-Localisation behaviour of the materials, and hence should be taken into account in constitutive modelling. In this research, a new approach is proposed for the integration of both size and orientation of a Localisation Band in the constitutive description beyond the onset of Localisation. Since a length scale related to the size of the Localisation Band appears in the model description, its post-Localisation response then scales with both the Band size and the size of the volume element containing it. Therefore, size effects are intrinsically included and post-Localisation behaviour is correctly captured, which helps ensure convergence of numerical solutions upon discretisation refinement in numerical analysis of boundary value problems. The concept together with implementation features of the framework and its performances at constitutive level and in the analysis of boundary value problems are presented in this paper.
Vinh P. Nguyen - One of the best experts on this subject based on the ideXlab platform.
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A size-dependent constitutive modelling framework for localised failure analysis
Computational Mechanics, 2016Co-Authors: Giang D Nguyen, Ha H Bui, Chi T. Nguyen, Vinh P. Nguyen, Luming ShenAbstract:Localised deformation of materials usually takes place in thin Bands during the nonlinear phase of the deformation process. The orientation and size of these Localisation Bands are important properties characterising the post-Localisation behaviour of the materials, and hence should be taken into account in constitutive modelling. In this research, a new approach is proposed for the integration of both size and orientation of a Localisation Band in the constitutive description beyond the onset of Localisation. Since a length scale related to the size of the Localisation Band appears in the model description, its post-Localisation response then scales with both the Band size and the size of the volume element containing it. Therefore, size effects are intrinsically included and post-Localisation behaviour is correctly captured, which helps ensure convergence of numerical solutions upon discretisation refinement in numerical analysis of boundary value problems. The concept together with implementation features of the framework and its performances at constitutive level and in the analysis of boundary value problems are presented in this paper.
