The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Paul Steinmann - One of the best experts on this subject based on the ideXlab platform.
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studies in elastic Fracture Mechanics based on the material force method
International Journal for Numerical Methods in Engineering, 2003Co-Authors: Ralf Denzer, Franz Josef Barth, Paul SteinmannAbstract:The object of this work is to discuss a further improvement of the material force method for non-linear hyperelastostatic Fracture Mechanics. We investigate the accuracy of the material force method within a 'modified boundary layer'-formulation using a Ramberg-Osgood material type for the sake of comparison. The proposed improvement leads to a reliable and very accurate method to compute the vectorial J-integral in Fracture Mechanics.
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application of material forces to hyperelastostatic Fracture Mechanics ii computational setting
International Journal of Solids and Structures, 2001Co-Authors: Paul Steinmann, D Ackermann, Franz Josef BarthAbstract:The concern of this work is a novel algorithmic treatment of hyperelastostatic Fracture Mechanics problems consistent to the notion of material forces within the geometrically nonlinear setting of continuum Mechanics. To this end, we consider the continuum Mechanics of material forces, as outlined in Part I of this work (P. Steinmann, Int. J. Solid Struct. 37, 7371–7391), which act, contrary to the common physical forces, on the material manifold or rather in the material space. In the sequel it is proposed to discretize the corresponding quasi-static balance of pseudo momentum by a standard Galerkin finite element procedure. As a result we obtain global discrete node point quantities, the material node point forces, which prove to be of the same qualitative and quantitative importance for the assessment of Fracture Mechanics problems as the classical J-integral.
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application of material forces to hyperelastostatic Fracture Mechanics i continuum mechanical setting
International Journal of Solids and Structures, 2000Co-Authors: Paul SteinmannAbstract:The concern of this work is a consequent exploitation of the notion of material forces for the application within hyperelastostatic Fracture Mechanics. Contrary to physical forces, material forces act on the material manifold, thus essentially representing the tendency of defects like cracks or inclusions to move relative to the ambient material. Based on the formulation of the appropriate quasi-static balance laws in the material space we aim at a fresh look onto classical aspects of hyperelastostatic Fracture Mechanics. Operating throughout within the geometrically nonlinear setting we emphasize on the one hand the duality of the direct and the inverse motion description and on the other hand we re-establish the classical path integrals from elementary equilibrium considerations in the material space.
J R Willis - One of the best experts on this subject based on the ideXlab platform.
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Fracture Mechanics for piezoelectric ceramics
Journal of The Mechanics and Physics of Solids, 1992Co-Authors: D M Barnett, J R WillisAbstract:We Study cracks either in piezoelectrics, or on interfaces between piezoelectrics and other materials such as metal electrodes or polymer matrices. The projected applications include ferroelectric actuators operating statically or cyclically, over the major portion of the samples, in the linear regime of the constitutive curve, but the elevated field around defects causes the materials to undergo hysteresis locally. The Fracture Mechanics viewpoint is adopted—that is, except for a region localized at the crack tip, the materials are taken to be linearly piezoelectric. The problem thus breaks into two subproblems: (i) determining the macroscopic field regarding the crack tip as a physically structureless point, and (ii) considering the hysteresis and other irreversible processes near the crack tip at a relevant microscopic level. The first Subproblem, which prompts a phenomenological Fracture theory, receives a thorough investigation in this paper. Griffith's energy accounting is extended to include energy change due to both deformation and polarization. Four modes of square root singularities are identified at the tip of a crack in a homogeneous piezoelectric. A new type of singularity is discovered around interface crack tips. Specifically, the singularities in general form two pairs: r12±iϵand r12±iϵ, where ϵ. and k are real numbers depending on the constitutive constants. Also solved is a class of boundary value problems involving many cracks on the interface between half-spaces. Fracture Mechanics are established for ferroelectric ceramics under smallscale hysteresis conditions, which facilitates the experimental study of Fracture resistance and fatigue crack growth under combined mechanical and electrical loading. Both poled and unpoled fcrroelectrie ceramics are discussed.
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Fracture Mechanics for piezoelectric ceramics
Journal of The Mechanics and Physics of Solids, 1992Co-Authors: Zhigang Suo, D M Barnett, C M Kuo, J R WillisAbstract:Abstract We Study cracks either in piezoelectrics, or on interfaces between piezoelectrics and other materials such as metal electrodes or polymer matrices. The projected applications include ferroelectric actuators operating statically or cyclically, over the major portion of the samples, in the linear regime of the constitutive curve, but the elevated field around defects causes the materials to undergo hysteresis locally. The Fracture Mechanics viewpoint is adopted—that is, except for a region localized at the crack tip, the materials are taken to be linearly piezoelectric. The problem thus breaks into two subproblems: (i) determining the macroscopic field regarding the crack tip as a physically structureless point, and (ii) considering the hysteresis and other irreversible processes near the crack tip at a relevant microscopic level. The first Subproblem, which prompts a phenomenological Fracture theory, receives a thorough investigation in this paper. Griffith's energy accounting is extended to include energy change due to both deformation and polarization. Four modes of square root singularities are identified at the tip of a crack in a homogeneous piezoelectric. A new type of singularity is discovered around interface crack tips. Specifically, the singularities in general form two pairs: r1/2±ieand r1/2±ie, where e. and k are real numbers depending on the constitutive constants. Also solved is a class of boundary value problems involving many cracks on the interface between half-spaces. Fracture Mechanics are established for ferroelectric ceramics under smallscale hysteresis conditions, which facilitates the experimental study of Fracture resistance and fatigue crack growth under combined mechanical and electrical loading. Both poled and unpoled fcrroelectrie ceramics are discussed.
Franz Josef Barth - One of the best experts on this subject based on the ideXlab platform.
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studies in elastic Fracture Mechanics based on the material force method
International Journal for Numerical Methods in Engineering, 2003Co-Authors: Ralf Denzer, Franz Josef Barth, Paul SteinmannAbstract:The object of this work is to discuss a further improvement of the material force method for non-linear hyperelastostatic Fracture Mechanics. We investigate the accuracy of the material force method within a 'modified boundary layer'-formulation using a Ramberg-Osgood material type for the sake of comparison. The proposed improvement leads to a reliable and very accurate method to compute the vectorial J-integral in Fracture Mechanics.
-
application of material forces to hyperelastostatic Fracture Mechanics ii computational setting
International Journal of Solids and Structures, 2001Co-Authors: Paul Steinmann, D Ackermann, Franz Josef BarthAbstract:The concern of this work is a novel algorithmic treatment of hyperelastostatic Fracture Mechanics problems consistent to the notion of material forces within the geometrically nonlinear setting of continuum Mechanics. To this end, we consider the continuum Mechanics of material forces, as outlined in Part I of this work (P. Steinmann, Int. J. Solid Struct. 37, 7371–7391), which act, contrary to the common physical forces, on the material manifold or rather in the material space. In the sequel it is proposed to discretize the corresponding quasi-static balance of pseudo momentum by a standard Galerkin finite element procedure. As a result we obtain global discrete node point quantities, the material node point forces, which prove to be of the same qualitative and quantitative importance for the assessment of Fracture Mechanics problems as the classical J-integral.
D M Barnett - One of the best experts on this subject based on the ideXlab platform.
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Fracture Mechanics for piezoelectric ceramics
Journal of The Mechanics and Physics of Solids, 1992Co-Authors: D M Barnett, J R WillisAbstract:We Study cracks either in piezoelectrics, or on interfaces between piezoelectrics and other materials such as metal electrodes or polymer matrices. The projected applications include ferroelectric actuators operating statically or cyclically, over the major portion of the samples, in the linear regime of the constitutive curve, but the elevated field around defects causes the materials to undergo hysteresis locally. The Fracture Mechanics viewpoint is adopted—that is, except for a region localized at the crack tip, the materials are taken to be linearly piezoelectric. The problem thus breaks into two subproblems: (i) determining the macroscopic field regarding the crack tip as a physically structureless point, and (ii) considering the hysteresis and other irreversible processes near the crack tip at a relevant microscopic level. The first Subproblem, which prompts a phenomenological Fracture theory, receives a thorough investigation in this paper. Griffith's energy accounting is extended to include energy change due to both deformation and polarization. Four modes of square root singularities are identified at the tip of a crack in a homogeneous piezoelectric. A new type of singularity is discovered around interface crack tips. Specifically, the singularities in general form two pairs: r12±iϵand r12±iϵ, where ϵ. and k are real numbers depending on the constitutive constants. Also solved is a class of boundary value problems involving many cracks on the interface between half-spaces. Fracture Mechanics are established for ferroelectric ceramics under smallscale hysteresis conditions, which facilitates the experimental study of Fracture resistance and fatigue crack growth under combined mechanical and electrical loading. Both poled and unpoled fcrroelectrie ceramics are discussed.
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Fracture Mechanics for piezoelectric ceramics
Journal of The Mechanics and Physics of Solids, 1992Co-Authors: Zhigang Suo, D M Barnett, C M Kuo, J R WillisAbstract:Abstract We Study cracks either in piezoelectrics, or on interfaces between piezoelectrics and other materials such as metal electrodes or polymer matrices. The projected applications include ferroelectric actuators operating statically or cyclically, over the major portion of the samples, in the linear regime of the constitutive curve, but the elevated field around defects causes the materials to undergo hysteresis locally. The Fracture Mechanics viewpoint is adopted—that is, except for a region localized at the crack tip, the materials are taken to be linearly piezoelectric. The problem thus breaks into two subproblems: (i) determining the macroscopic field regarding the crack tip as a physically structureless point, and (ii) considering the hysteresis and other irreversible processes near the crack tip at a relevant microscopic level. The first Subproblem, which prompts a phenomenological Fracture theory, receives a thorough investigation in this paper. Griffith's energy accounting is extended to include energy change due to both deformation and polarization. Four modes of square root singularities are identified at the tip of a crack in a homogeneous piezoelectric. A new type of singularity is discovered around interface crack tips. Specifically, the singularities in general form two pairs: r1/2±ieand r1/2±ie, where e. and k are real numbers depending on the constitutive constants. Also solved is a class of boundary value problems involving many cracks on the interface between half-spaces. Fracture Mechanics are established for ferroelectric ceramics under smallscale hysteresis conditions, which facilitates the experimental study of Fracture resistance and fatigue crack growth under combined mechanical and electrical loading. Both poled and unpoled fcrroelectrie ceramics are discussed.
E De Luycker - One of the best experts on this subject based on the ideXlab platform.
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x fem in isogeometric analysis for linear Fracture Mechanics
International Journal for Numerical Methods in Engineering, 2011Co-Authors: E De Luycker, David J Benson, Ted Belytschko, Yuri Bazilevs, Mingchen HsuAbstract:The extended finite element method (X-FEM) has proven to be an accurate, robust method for solving problems in Fracture Mechanics. X-FEM has typically been used with elements using linear basis functions, although some work has been performed using quadratics. In the current work, the X-FEM formulation is incorporated into isogeometric analysis to obtain solutions with higher order convergence rates for problems in linear Fracture Mechanics. In comparison with X-FEM with conventional finite elements of equal degree, the NURBS-based isogeometric analysis gives equal asymptotic convergence rates and equal accuracy with fewer degrees of freedom (DOF). Results for linear through quartic NURBS basis functions are presented for a multiplicity of one or a multiplicity equal the degree.
