The Experts below are selected from a list of 29433 Experts worldwide ranked by ideXlab platform
Juner Zhu - One of the best experts on this subject based on the ideXlab platform.
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Large-Deformation Plasticity and fracture behavior of pure lithium under various stress states
Acta Materialia, 2021Co-Authors: Tobias Sedlatschek, Junhe Lian, Menglei Jiang, Tomasz Wierzbicki, Martin Z. Bazant, Juner ZhuAbstract:Abstract Although lithium-metal anodes are being extensively examined in research projects aiming at pushing the energy density of lithium batteries to its limit, the knowledge about the mechanical properties of pure lithium is insufficient in two aspects. First, most of the available data focuses either on nano- and micro-scale single-crystalline lithium or on macro-scale bulk material. Second, those tests were commonly performed via uniaxial tests in which the stress states were simple or nanoindentation. This work aims at bridging these gaps by performing a systematic experimental program under various stress states on small-sized specimens and by developing a Plasticity model that can capture the important characteristics. Based on these experimental and computational findings, the added value on the understanding of the Deformation and failure mechanisms of lithium under various stress states and a first quantitative description on the Plasticity anisotropy on lithium is provided. In order to manufacture the required complex-shaped specimens for the five different stress states (uniaxial tension, notched tension with two different radii, central hole tension, and simple shear), a method which allows safe laser cutting of thick lithium foil in argon atmosphere is developed. The tensile tests are conducted in pure argon as well as in air to quantify the effect of oxidation on the strength of lithium. By means of post-mortem microstructural examinations, two active slip systems and cross-slip are observed. Lithium fractures in a perfectly ductile manner when the specimen thickness is reduced to zero due to localized necking. Digital image correlation analysis shows that the lithium foil is highly anisotropic in the through-thickness direction although it is in-plane isotropic. By using a rate-dependent transverse isotropic model, a satisfactory prediction of the five experiments is provided.
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Large-Deformation Plasticity and Fracture Behavior of Pure Lithium Under Various Stress States
SSRN Electronic Journal, 2020Co-Authors: Tobias Sedlatschek, Junhe Lian, Menglei Jiang, Tomasz Wierzbicki, Martin Z. Bazant, Juner ZhuAbstract:Although lithium-metal anodes are being extensively examined in research projects aiming at pushing the energy density of lithium batteries to its limit, the knowledge about the mechanical properties of pure lithium is insufficient in two aspects. First, available data focuses either on nano- and micro-scale single crystalline lithium or on macro-scale bulk material. Second, those tests were commonly performed via uniaxial tests in which the stress states were simple. This work aims at bridging these gaps by performing a systematic experimental program under various stress states on small-sized specimens and by developing a Plasticity model that can capture the important characteristics. Based on these experimental and computational findings, the added value on the understanding of the Deformation and failure mechanisms of lithium under various stress states and a first quantitative description on the Plasticity anisotropy on lithium is provided. In order to manufacture the required complex-shaped specimens for the five different stress states (uniaxial tension, notched tension with two different radii, central hole tension, and simple shear), a method which allows safe laser cutting of thick lithium foil in argon atmosphere is developed. The tensile tests are conducted in pure argon as well as in air to quantify the effect of oxidation on the strength of lithium. By means of post-mortem microstructural examinations, two active slip systems and cross-slip are observed. Lithium fractures in a perfectly ductile manner when the specimen thickness is reduced to zero due to localized necking. Digital image correlation analysis shows that the lithium foil is highly anisotropic in the through-thickness direction although it is in-plane isotropic. By using a rate-dependent transverse isotropic model, a satisfactory prediction of the five experiments is provided.
Wakako Araki - One of the best experts on this subject based on the ideXlab platform.
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asymptotic analysis for the singular stress behaviour around an interface edge of dissimilar power law hardening materials joint
Key Engineering Materials, 2011Co-Authors: Md Arefin Kowser, Yoshio Arai, Wakako ArakiAbstract:An asymptotic analysis for singular stress fields around an interface-edge of dissimilar power-law hardening materials joint has been presented under plane strain condition and J2 Deformation Plasticity theory. Both the balance of force and the continuity of displacement are satisfied on the interface. In the higher order approximation, the nonlinear effective stress term was expanded by Taylor series. An iteration method is proposed for the determination of singular fields around interface edge. Multiple stress singular terms exist for in the higher order approximation. The order of stress singularity has a dependency with the combination of hardening exponents, .
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an iteration method for singular fields around an interface edge of elastic power law hardening materials joint
Journal of Solid Mechanics and Materials Engineering, 2010Co-Authors: Md Arefin Kowser, Yoshio Arai, Wakako ArakiAbstract:The objective of present study is to present solution to determine the stress and displacement fields around an interface edge of a joint formed by quarter planes in which materials behaves as an elastic and a power-law hardening material. J2-Deformation Plasticity theory under plane strain condition is assumed for the power-law hardening material. Both the balance of force and the continuity of displacements are satisfied on the interface iteratively. The stress fields are found to be singular with the type of 1 i r λ − singularity from the i-th order approximation, where r is the radial distance from the interface. The power of r in the stress equation depends on the hardening exponent n. ( ) 1
Tobias Sedlatschek - One of the best experts on this subject based on the ideXlab platform.
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Large-Deformation Plasticity and fracture behavior of pure lithium under various stress states
Acta Materialia, 2021Co-Authors: Tobias Sedlatschek, Junhe Lian, Menglei Jiang, Tomasz Wierzbicki, Martin Z. Bazant, Juner ZhuAbstract:Abstract Although lithium-metal anodes are being extensively examined in research projects aiming at pushing the energy density of lithium batteries to its limit, the knowledge about the mechanical properties of pure lithium is insufficient in two aspects. First, most of the available data focuses either on nano- and micro-scale single-crystalline lithium or on macro-scale bulk material. Second, those tests were commonly performed via uniaxial tests in which the stress states were simple or nanoindentation. This work aims at bridging these gaps by performing a systematic experimental program under various stress states on small-sized specimens and by developing a Plasticity model that can capture the important characteristics. Based on these experimental and computational findings, the added value on the understanding of the Deformation and failure mechanisms of lithium under various stress states and a first quantitative description on the Plasticity anisotropy on lithium is provided. In order to manufacture the required complex-shaped specimens for the five different stress states (uniaxial tension, notched tension with two different radii, central hole tension, and simple shear), a method which allows safe laser cutting of thick lithium foil in argon atmosphere is developed. The tensile tests are conducted in pure argon as well as in air to quantify the effect of oxidation on the strength of lithium. By means of post-mortem microstructural examinations, two active slip systems and cross-slip are observed. Lithium fractures in a perfectly ductile manner when the specimen thickness is reduced to zero due to localized necking. Digital image correlation analysis shows that the lithium foil is highly anisotropic in the through-thickness direction although it is in-plane isotropic. By using a rate-dependent transverse isotropic model, a satisfactory prediction of the five experiments is provided.
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Large-Deformation Plasticity and Fracture Behavior of Pure Lithium Under Various Stress States
SSRN Electronic Journal, 2020Co-Authors: Tobias Sedlatschek, Junhe Lian, Menglei Jiang, Tomasz Wierzbicki, Martin Z. Bazant, Juner ZhuAbstract:Although lithium-metal anodes are being extensively examined in research projects aiming at pushing the energy density of lithium batteries to its limit, the knowledge about the mechanical properties of pure lithium is insufficient in two aspects. First, available data focuses either on nano- and micro-scale single crystalline lithium or on macro-scale bulk material. Second, those tests were commonly performed via uniaxial tests in which the stress states were simple. This work aims at bridging these gaps by performing a systematic experimental program under various stress states on small-sized specimens and by developing a Plasticity model that can capture the important characteristics. Based on these experimental and computational findings, the added value on the understanding of the Deformation and failure mechanisms of lithium under various stress states and a first quantitative description on the Plasticity anisotropy on lithium is provided. In order to manufacture the required complex-shaped specimens for the five different stress states (uniaxial tension, notched tension with two different radii, central hole tension, and simple shear), a method which allows safe laser cutting of thick lithium foil in argon atmosphere is developed. The tensile tests are conducted in pure argon as well as in air to quantify the effect of oxidation on the strength of lithium. By means of post-mortem microstructural examinations, two active slip systems and cross-slip are observed. Lithium fractures in a perfectly ductile manner when the specimen thickness is reduced to zero due to localized necking. Digital image correlation analysis shows that the lithium foil is highly anisotropic in the through-thickness direction although it is in-plane isotropic. By using a rate-dependent transverse isotropic model, a satisfactory prediction of the five experiments is provided.
Dennis M. Kochmann - One of the best experts on this subject based on the ideXlab platform.
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A variational constitutive model for slip-twinning interactions in hcp metals: Application to single- and polycrystalline magnesium
International Journal of Plasticity, 2015Co-Authors: Yingrui Chang, Dennis M. KochmannAbstract:We present a constitutive model for hcp metals which is based on variational constitutive updates of plastic slips and twin volume fractions and accounts for the related lattice reorientation mechanisms. The model is applied to single- and polycrystalline pure magnesium. We outline the finite-Deformation Plasticity model combining basal, pyramidal, and prismatic dislocation activity as well as a convexification-based approach for Deformation twinning. A comparison with experimental data from single-crystal tension-compression experiments validates the model and serves for parameter identification. The extension to polycrystals via both Taylor-type modeling and finite element simulations shows a characteristic stress-strain response that agrees well with experimental observations for polycrystalline magnesium. The presented continuum model does not aim to represent the full details of individual twin-dislocation interactions; yet, it is sufficiently efficient to allow for finite element simulations while qualitatively capturing the underlying microstructural Deformation mechanisms.
Fadi Gharzeddine - One of the best experts on this subject based on the ideXlab platform.
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finite Deformation Plasticity in principal axes from a manifold to the euclidean setting
Computer Methods in Applied Mechanics and Engineering, 1999Co-Authors: Adnan Ibrahimbegovic, Fadi GharzeddineAbstract:Abstract This contribution presents a link between early developments in finite Deformation Plasticity, where the notion of a covariant formulation is introduced and employed, and more recent developments, where rediscovery of a fundamental work of Hill on the method of principal axes led to a very efficient implementation scheme. More precisely, we demonstrate how to develop a covariant theory of finite Deformation Plasticity in an invariant form, by making use of the elastic principal stretches. We also show how to implement principal axis formulation in the framework of manifold, to carry out all the necessary manipulations by exploiting the Lie derivative formalism and eventually to simplify the final result to the Euclidean setting. Much of our work on numerical implementation reflects the fruitful cross-fertilization of ideas with those from theoretical formulation. In particular, we show how the operator split method, which is typically used to simplify the plastic flow computation, can also be used to reduce the computational cost related to the special finite element interpolation schemes based on incompatible modes. The latter proves to be an indispensable ingredient for accommodating the near-incompressibility constraint arising in the finite Deformation deviatoric Plasticity. An important advantage of the proposed formulation as opposed to alternative remedies (e.g. B-bar method) is that the basic structure of the governing equations need not be modified.