The Experts below are selected from a list of 7035 Experts worldwide ranked by ideXlab platform
Frédéric Barlat - One of the best experts on this subject based on the ideXlab platform.
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Parameter identification of the homogeneous anisotropic Hardening Model using the virtual fields method
International Journal of Material Forming, 2015Co-Authors: Jiawei Fu, Frédéric BarlatAbstract:In this paper, the virtual fields method is applied to identify the constitutive parameters of the homogeneous yield function-based anisotropic Hardening Model. The procedure, previously developed for isotropic Hardening law, is extended to the anisotropic case in this study. For validation purpose, a finite element Model is developed to check the feasibility of the proposed methodology in retrieving the target constitutive parameters. The identification results are critically discussed. The suitability of this finite element Model is also assessed with a view to future experiments.
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stress update algorithm for enhanced homogeneous anisotropic Hardening Model
Computer Methods in Applied Mechanics and Engineering, 2015Co-Authors: Hyuk Jong Bong, Frédéric BarlatAbstract:Abstract A stress integration algorithm is provided for a novel homogeneous-yield-function-based anisotropic Hardening (HAH) Model. The new Model is an extension of the original HAH Model that describes cross-Hardening or softening of a sheet metal under an orthogonal strain path change. A semi-explicit integration scheme for the stress update is utilized to efficiently handle the gradient of the distorted yield surface during complex strain path changes, as originally proposed by Lee et al. (2012). Validations of the algorithm developed were conducted by comparing the predicted stress–strain curves of dual-phase (DP) 780 and extra-deep-drawing-quality (EDDQ) steels with experimental stress–strain responses observed under cross-loading conditions. Finally, the accuracy of the proposed finite element (FE) formulations was assessed by r -value prediction and preparation of iso-error maps.
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enhancements of homogenous anisotropic Hardening Model and application to mild and dual phase steels
International Journal of Plasticity, 2014Co-Authors: Frédéric Barlat, J Gracio, Gabriela Vincze, E F Rauch, C N TomeAbstract:Abstract The formulation of the so-called homogeneous anisotropic Hardening (HAH) Model, which was originally proposed in Barlat et al. (2011) , is refined. With the new features, this distortional plasticity-based constitutive Model predicts the mechanical response of metals subjected to non-proportional loading with improved accuracy, in particular for cross-loading. In that case, applications to two different steels are provided for illustration purposes. For mild steel, the stress overshoot of the monotonic flow curve observed during a double load change is well reproduced by the Model. In addition, for a dual-phase steel deformed in a two-step tension test with axes at 45° from each other, the new features allow the reloading yield stress to be lower than the unloading flow stress, in good agreement with experimental observations.
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Material Modelling and Springback Analysis for Multi-stage Rotary Draw Bending of Thin-walled Tube Using Homogeneous Anisotropic Hardening Model☆
Procedia Engineering, 2014Co-Authors: Juan Liao, Frédéric Barlat, José GrácioAbstract:Abstract The aim of this paper is to compare several Hardening Models and to show their relevance for the prediction of springback and deformation of an asymmetric aluminium alloy tube in multi-stage rotary draw bending process. A three-dimensional finite-element Model of the process is developed using the ABAQUS code. For material Modelling, the newly developed homogeneous anisotropic Hardening Model is adopted to capture the Bauschinger effect and transient Hardening behaviour of the aluminium alloy tube subjected to non-proportional loading. The material parameters of the Hardening Model are obtained from uniaxial tension and forward-reverse shear test results of tube specimens. This work shows that this approach reproduces the transient Bauschinger behaviour of the material reasonably well. However, a curve-crossing phenomenon observed for this material cannot be captured by the homogeneous anisotropic Hardening Model. For comparison purpose, the isotropic and combined isotropic-kinematic Hardening Models are also adopted for the analysis of the same problem. The predictions of springback and cross-section deformation based on these Models are discussed.
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a dislocation based Hardening Model incorporated into an anisotropic Hardening approach
Computational Materials Science, 2013Co-Authors: J Gracio, Gabriela Vincze, E F Rauch, Frédéric BarlatAbstract:Abstract The plastic flow behaviors under monotonic and forward–reverse loading were measured and Modeled using a simple dislocation density-based Model coupled with the homogeneous yield function anisotropic Hardening (HAH) approach. The former Model captures the effect of dislocation annihilation due to load reversal and the storage of newly generated dislocations that, overall, results in the stagnation of the strain Hardening rate. The latter Model reproduces the mechanical response of the Bauschinger effect and permanent softening phenomenon. After implementing the constitutive Model into a finite element software, a detailed parametric study was performed to clarify the role of each constitutive parameter. In addition, this Model was applied for the prediction of the flow curves of three different steel sheet samples under forward–reverse simple shear deformation. It was shown that this approach reasonably well reproduces the complex mechanical behavior of the steel samples. Finally, this physically based constitutive Model was used to predict the springback of a realistic part after forming in order to prove its accuracy, robustness and efficiency as compared with another well accepted phenomenological isotropic-kinematic Hardening Model.
E F Rauch - One of the best experts on this subject based on the ideXlab platform.
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enhancements of homogenous anisotropic Hardening Model and application to mild and dual phase steels
International Journal of Plasticity, 2014Co-Authors: Frédéric Barlat, J Gracio, Gabriela Vincze, E F Rauch, C N TomeAbstract:Abstract The formulation of the so-called homogeneous anisotropic Hardening (HAH) Model, which was originally proposed in Barlat et al. (2011) , is refined. With the new features, this distortional plasticity-based constitutive Model predicts the mechanical response of metals subjected to non-proportional loading with improved accuracy, in particular for cross-loading. In that case, applications to two different steels are provided for illustration purposes. For mild steel, the stress overshoot of the monotonic flow curve observed during a double load change is well reproduced by the Model. In addition, for a dual-phase steel deformed in a two-step tension test with axes at 45° from each other, the new features allow the reloading yield stress to be lower than the unloading flow stress, in good agreement with experimental observations.
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a dislocation based Hardening Model incorporated into an anisotropic Hardening approach
Computational Materials Science, 2013Co-Authors: J Gracio, Gabriela Vincze, E F Rauch, Frédéric BarlatAbstract:Abstract The plastic flow behaviors under monotonic and forward–reverse loading were measured and Modeled using a simple dislocation density-based Model coupled with the homogeneous yield function anisotropic Hardening (HAH) approach. The former Model captures the effect of dislocation annihilation due to load reversal and the storage of newly generated dislocations that, overall, results in the stagnation of the strain Hardening rate. The latter Model reproduces the mechanical response of the Bauschinger effect and permanent softening phenomenon. After implementing the constitutive Model into a finite element software, a detailed parametric study was performed to clarify the role of each constitutive parameter. In addition, this Model was applied for the prediction of the flow curves of three different steel sheet samples under forward–reverse simple shear deformation. It was shown that this approach reasonably well reproduces the complex mechanical behavior of the steel samples. Finally, this physically based constitutive Model was used to predict the springback of a realistic part after forming in order to prove its accuracy, robustness and efficiency as compared with another well accepted phenomenological isotropic-kinematic Hardening Model.
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extension of homogeneous anisotropic Hardening Model to cross loading with latent effects
International Journal of Plasticity, 2013Co-Authors: Frédéric Barlat, José Grácio, E F Rauch, Jinjin Ha, Gabriela VinczeAbstract:Abstract The homogeneous anisotropic Hardening (HAH) approach, which captures the Bauschinger effect in metallic materials effectively during load reversal, was extended to cross-loading cases with latent Hardening effects. This continuum approach is based on the physical understanding of dislocation structure evolution during strain path changes but does not include the concept of kinematic Hardening. The Model was well validated for a deep drawing quality sheet sample. However, for a dual-phase steel, differences between predicted and experimental results were observed and discussed. Based on these results, additional validation tests and further improvement in the approach were suggested.
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work Hardening Model for polycrystalline metals under strain reversal at large strains
Acta Materialia, 2007Co-Authors: E F Rauch, Frédéric Barlat, J GracioAbstract:Abstract The mechanical behaviours under reversed strain of low carbon steels and aluminium alloys are reviewed and Modelled with a simple approach based on the evolutionary laws of two dislocation densities related respectively to the forward and the backward straining. In essence, it is the competition between the annihilation of the dislocations that were created during the prestrain and the storage of newly created dislocations that lead to the observed stagnation of the Hardening rate. Textural effects as well as back stresses are shown to extend or to reduce the stress–strain plateau but are not responsible for it.
Gabriela Vincze - One of the best experts on this subject based on the ideXlab platform.
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enhancements of homogenous anisotropic Hardening Model and application to mild and dual phase steels
International Journal of Plasticity, 2014Co-Authors: Frédéric Barlat, J Gracio, Gabriela Vincze, E F Rauch, C N TomeAbstract:Abstract The formulation of the so-called homogeneous anisotropic Hardening (HAH) Model, which was originally proposed in Barlat et al. (2011) , is refined. With the new features, this distortional plasticity-based constitutive Model predicts the mechanical response of metals subjected to non-proportional loading with improved accuracy, in particular for cross-loading. In that case, applications to two different steels are provided for illustration purposes. For mild steel, the stress overshoot of the monotonic flow curve observed during a double load change is well reproduced by the Model. In addition, for a dual-phase steel deformed in a two-step tension test with axes at 45° from each other, the new features allow the reloading yield stress to be lower than the unloading flow stress, in good agreement with experimental observations.
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a dislocation based Hardening Model incorporated into an anisotropic Hardening approach
Computational Materials Science, 2013Co-Authors: J Gracio, Gabriela Vincze, E F Rauch, Frédéric BarlatAbstract:Abstract The plastic flow behaviors under monotonic and forward–reverse loading were measured and Modeled using a simple dislocation density-based Model coupled with the homogeneous yield function anisotropic Hardening (HAH) approach. The former Model captures the effect of dislocation annihilation due to load reversal and the storage of newly generated dislocations that, overall, results in the stagnation of the strain Hardening rate. The latter Model reproduces the mechanical response of the Bauschinger effect and permanent softening phenomenon. After implementing the constitutive Model into a finite element software, a detailed parametric study was performed to clarify the role of each constitutive parameter. In addition, this Model was applied for the prediction of the flow curves of three different steel sheet samples under forward–reverse simple shear deformation. It was shown that this approach reasonably well reproduces the complex mechanical behavior of the steel samples. Finally, this physically based constitutive Model was used to predict the springback of a realistic part after forming in order to prove its accuracy, robustness and efficiency as compared with another well accepted phenomenological isotropic-kinematic Hardening Model.
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extension of homogeneous anisotropic Hardening Model to cross loading with latent effects
International Journal of Plasticity, 2013Co-Authors: Frédéric Barlat, José Grácio, E F Rauch, Jinjin Ha, Gabriela VinczeAbstract:Abstract The homogeneous anisotropic Hardening (HAH) approach, which captures the Bauschinger effect in metallic materials effectively during load reversal, was extended to cross-loading cases with latent Hardening effects. This continuum approach is based on the physical understanding of dislocation structure evolution during strain path changes but does not include the concept of kinematic Hardening. The Model was well validated for a deep drawing quality sheet sample. However, for a dual-phase steel, differences between predicted and experimental results were observed and discussed. Based on these results, additional validation tests and further improvement in the approach were suggested.
C N Tome - One of the best experts on this subject based on the ideXlab platform.
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enhancements of homogenous anisotropic Hardening Model and application to mild and dual phase steels
International Journal of Plasticity, 2014Co-Authors: Frédéric Barlat, J Gracio, Gabriela Vincze, E F Rauch, C N TomeAbstract:Abstract The formulation of the so-called homogeneous anisotropic Hardening (HAH) Model, which was originally proposed in Barlat et al. (2011) , is refined. With the new features, this distortional plasticity-based constitutive Model predicts the mechanical response of metals subjected to non-proportional loading with improved accuracy, in particular for cross-loading. In that case, applications to two different steels are provided for illustration purposes. For mild steel, the stress overshoot of the monotonic flow curve observed during a double load change is well reproduced by the Model. In addition, for a dual-phase steel deformed in a two-step tension test with axes at 45° from each other, the new features allow the reloading yield stress to be lower than the unloading flow stress, in good agreement with experimental observations.
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application of a substructure based Hardening Model to copper under loading path changes
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2004Co-Authors: Sivasambu Mahesh, C N Tome, Rodney J Mccabe, G C Kaschner, A Misra, Irene J BeyerleinAbstract:In addition to texture, plastic anisotropy of a polycrystalline fcc metal stems from the directional nature of the dislocation substructure within individual grains. This produces the marked work Hardening or softening observed immediately following load path changes. Following the framework of Peeters et al., in bcc steel, we develop a dislocation substructure evolution-based stage III Hardening Model for copper, capable of capturing the constitutive response under load path changes. The present Model accounts for the more complicated substructure geometry in fcc metals than in bcc. Using an optimization algorithm, the parameters governing substructure evolution in the Model are fit to experimental stress-strain curves obtained during compression along the three orthogonal directions in samples previously rolled to various reductions. These experiments approximate monotonic, reverse, and cross-load paths. With parameters suitably chosen, the substructure Model, embedded into a self-consistent polycrystal plasticity Model, is able to reproduce the measured flow stress response of copper during load path change experiments. The sensitivity of the parameters to the assumed substructure geometry and their uniqueness are also discussed.
J Gracio - One of the best experts on this subject based on the ideXlab platform.
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enhancements of homogenous anisotropic Hardening Model and application to mild and dual phase steels
International Journal of Plasticity, 2014Co-Authors: Frédéric Barlat, J Gracio, Gabriela Vincze, E F Rauch, C N TomeAbstract:Abstract The formulation of the so-called homogeneous anisotropic Hardening (HAH) Model, which was originally proposed in Barlat et al. (2011) , is refined. With the new features, this distortional plasticity-based constitutive Model predicts the mechanical response of metals subjected to non-proportional loading with improved accuracy, in particular for cross-loading. In that case, applications to two different steels are provided for illustration purposes. For mild steel, the stress overshoot of the monotonic flow curve observed during a double load change is well reproduced by the Model. In addition, for a dual-phase steel deformed in a two-step tension test with axes at 45° from each other, the new features allow the reloading yield stress to be lower than the unloading flow stress, in good agreement with experimental observations.
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a dislocation based Hardening Model incorporated into an anisotropic Hardening approach
Computational Materials Science, 2013Co-Authors: J Gracio, Gabriela Vincze, E F Rauch, Frédéric BarlatAbstract:Abstract The plastic flow behaviors under monotonic and forward–reverse loading were measured and Modeled using a simple dislocation density-based Model coupled with the homogeneous yield function anisotropic Hardening (HAH) approach. The former Model captures the effect of dislocation annihilation due to load reversal and the storage of newly generated dislocations that, overall, results in the stagnation of the strain Hardening rate. The latter Model reproduces the mechanical response of the Bauschinger effect and permanent softening phenomenon. After implementing the constitutive Model into a finite element software, a detailed parametric study was performed to clarify the role of each constitutive parameter. In addition, this Model was applied for the prediction of the flow curves of three different steel sheet samples under forward–reverse simple shear deformation. It was shown that this approach reasonably well reproduces the complex mechanical behavior of the steel samples. Finally, this physically based constitutive Model was used to predict the springback of a realistic part after forming in order to prove its accuracy, robustness and efficiency as compared with another well accepted phenomenological isotropic-kinematic Hardening Model.
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work Hardening Model for polycrystalline metals under strain reversal at large strains
Acta Materialia, 2007Co-Authors: E F Rauch, Frédéric Barlat, J GracioAbstract:Abstract The mechanical behaviours under reversed strain of low carbon steels and aluminium alloys are reviewed and Modelled with a simple approach based on the evolutionary laws of two dislocation densities related respectively to the forward and the backward straining. In essence, it is the competition between the annihilation of the dislocations that were created during the prestrain and the storage of newly created dislocations that lead to the observed stagnation of the Hardening rate. Textural effects as well as back stresses are shown to extend or to reduce the stress–strain plateau but are not responsible for it.
