The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform
Xinwei Wang - One of the best experts on this subject based on the ideXlab platform.
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an experimental study on Subsequent Yield Surface after finite shear prestraining
International Journal of Plasticity, 1993Co-Authors: Akhtar S Khan, Xinwei WangAbstract:Abstract An equimodulus Surface is introduced and the Subsequent Yield Surface after large finite shear prestraining is experimentally investogated. Fully annealed, thin-walled copper tubular specimens were subjected to large torsional loading and partial unloading; strain gages were carefully mounted on the specimen after the application of pure shear loading. Specimens were then subjected to various combined tension-torsion loadings. Influences of he von Mises and Tresca equivalent offset strains on the Subsequent Yield Surfaces are studied. On examining the experimental results reported in this article, it was found that the smaller the offset strains, the more distorted are the Subsequent Yield Surfaces. At the torsional preloading point, a rounded corner was developed, whereas in the region opposite to the preloading point, the Subsequent Yield Surface was flattened. When large von Mises offset strains were used, the corresponding Subsequent Yield Surfaces passed through the von Mises loading Surface. But this was not the case when Tresca offset strains were used. The Subsequent Yield Surface determined by the back extrapolation method was almost completely outside the von Mises loading Surface. On the other hand, the Subsequent Yield Surface determined by the back extrapolation method was close to the Tresca loading Surface. It is also found that the equimodulus Surface is distorted and cannot simply be described by the combined kinematic and isotropic hardening rule.
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On Subsequent Yield Surfaces after Finite Shear Pre-Straining
Anisotropy and Localization of Plastic Deformation, 1991Co-Authors: Xinwei Wang, Akhtar S KhanAbstract:The Subsequent Yield Surface for an annealed OFHC copper after finite shear pre-loading is experimentally investigated. It was found that when large offset strains or back extrapolation Yield stresses were used, the corresponding Subsequent Yield Surfaces were partially or completely outside the von Mises loading Surface. On the other hand, the Subsequent Yield Surface determined by the back extrapolation method was close to the Tresca loading Surface.
Akhtar S Khan - One of the best experts on this subject based on the ideXlab platform.
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an experimental study on Subsequent Yield Surface after finite shear prestraining
International Journal of Plasticity, 1993Co-Authors: Akhtar S Khan, Xinwei WangAbstract:Abstract An equimodulus Surface is introduced and the Subsequent Yield Surface after large finite shear prestraining is experimentally investogated. Fully annealed, thin-walled copper tubular specimens were subjected to large torsional loading and partial unloading; strain gages were carefully mounted on the specimen after the application of pure shear loading. Specimens were then subjected to various combined tension-torsion loadings. Influences of he von Mises and Tresca equivalent offset strains on the Subsequent Yield Surfaces are studied. On examining the experimental results reported in this article, it was found that the smaller the offset strains, the more distorted are the Subsequent Yield Surfaces. At the torsional preloading point, a rounded corner was developed, whereas in the region opposite to the preloading point, the Subsequent Yield Surface was flattened. When large von Mises offset strains were used, the corresponding Subsequent Yield Surfaces passed through the von Mises loading Surface. But this was not the case when Tresca offset strains were used. The Subsequent Yield Surface determined by the back extrapolation method was almost completely outside the von Mises loading Surface. On the other hand, the Subsequent Yield Surface determined by the back extrapolation method was close to the Tresca loading Surface. It is also found that the equimodulus Surface is distorted and cannot simply be described by the combined kinematic and isotropic hardening rule.
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On Subsequent Yield Surfaces after Finite Shear Pre-Straining
Anisotropy and Localization of Plastic Deformation, 1991Co-Authors: Xinwei Wang, Akhtar S KhanAbstract:The Subsequent Yield Surface for an annealed OFHC copper after finite shear pre-loading is experimentally investigated. It was found that when large offset strains or back extrapolation Yield stresses were used, the corresponding Subsequent Yield Surfaces were partially or completely outside the von Mises loading Surface. On the other hand, the Subsequent Yield Surface determined by the back extrapolation method was close to the Tresca loading Surface.
K Nomura - One of the best experts on this subject based on the ideXlab platform.
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use of abrupt strain path change for determining Subsequent Yield Surface experimental study with metal sheets
Acta Materialia, 2000Co-Authors: Toshihiko Kuwabara, Mitsutoshi Kuroda, Viggo Tvergaard, K NomuraAbstract:A basic idea for a method for determining the Subsequent Yield Surface in the vicinity of a current loading point by using an abrupt strain path change has been proposed recently by Kuroda and Tvergaard (Acta mater., 1999, 47, 3879). The proposed method is applied to real experimental studies. In a biaxial tensile testing apparatus, a cruciform specimen is used, with the strains measured by a biaxial-strain gauge. Then, with the hydraulic pressure of two sets of opposing hydraulic cylinders servo-controlled independently, the testing apparatus can be used to prescribe an abrupt change of the strain path. Both a cold-rolled steel sheet and an aluminum alloy sheet are investigated. The differences between the Yield Surface shapes found by the strain path change procedure and the shapes found by probing the Yield points from the elastic region are shown and discussed for different cases.
Jiashuo Qi - One of the best experts on this subject based on the ideXlab platform.
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investigation on the evolution of Subsequent Yield Surface of pure aluminum under changing loading paths considering microstructure effects
Journal of Materials Engineering and Performance, 2020Co-Authors: Jiashuo QiAbstract:The anisotropy behavior is one of the most important key issues in the simulation of sheet metal forming, which can highly affect the prediction accuracy of metal forming behavior, especially under complex loading paths. In this study, the initial and Subsequent Yield Surfaces of the pure aluminum material are numerically investigated through the representative volume element (RVE) methodology. The crystal plasticity theory is chosen to represent the microscopic elastoplastic behavior of pure aluminum, and its polycrystalline geometrical model is built by the Voronoi algorithm. Together with user material subroutine, the initial and Subsequent Yield Surfaces evolution of pure aluminum under different loading paths is simulated in commercial software ABAQUS/Implicit. Through the investigation, the great influence of the microtexture on the obtained inhomogeneous stress distribution of RVE model can be presented. Meanwhile, the effect of the loading directions and the predeformation is also investigated and discussed. The shape of the Subsequent Yield Surface is also strongly dependent on both the Yield definition and direction of preloading, and the high anisotropy phenomena appear corresponding to different Yield definitions. At the same time, the pole figures at different forming stages are given, and the evolution of polycrystalline texture is analyzed and predicted. It can be concluded that some strong relationship between the texture evolution, the inhomogeneous stress field, and the Subsequent Yield Surface evolution is proved and discussed. This study provides a good methodology to study the Yield Surface evolution of aluminum together with the crystal plasticity theory, with considering the evolution of the microtexture evolution during the plastic deformation of the metal.
Viggo Tvergaard - One of the best experts on this subject based on the ideXlab platform.
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use of abrupt strain path change for determining Subsequent Yield Surface experimental study with metal sheets
Acta Materialia, 2000Co-Authors: Toshihiko Kuwabara, Mitsutoshi Kuroda, Viggo Tvergaard, K NomuraAbstract:A basic idea for a method for determining the Subsequent Yield Surface in the vicinity of a current loading point by using an abrupt strain path change has been proposed recently by Kuroda and Tvergaard (Acta mater., 1999, 47, 3879). The proposed method is applied to real experimental studies. In a biaxial tensile testing apparatus, a cruciform specimen is used, with the strains measured by a biaxial-strain gauge. Then, with the hydraulic pressure of two sets of opposing hydraulic cylinders servo-controlled independently, the testing apparatus can be used to prescribe an abrupt change of the strain path. Both a cold-rolled steel sheet and an aluminum alloy sheet are investigated. The differences between the Yield Surface shapes found by the strain path change procedure and the shapes found by probing the Yield points from the elastic region are shown and discussed for different cases.
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use of abrupt strain path change for determining Subsequent Yield Surface illustrations of basic idea
Acta Materialia, 1999Co-Authors: Mitsutoshi Kuroda, Viggo TvergaardAbstract:Abstract For elastic–plastic materials, a new method is proposed for determining the shape of the Subsequent Yield Surface in the vicinity of a current loading point. A proportional strain path is prescribed until the loading point of interest has been reached, then an abrupt strain path change is prescribed, which makes the stress point move quickly along the Yield Surface. It is assumed that a closed-loop testing machine is used for the experiment, so that the strain path can be prescribed according to strain gauge measurements. Relative to the standard method of determining Yield Surface shapes by probing in many different stress directions from the elastic region, using some chosen plastic strain offset, the main advantage of the proposed method is that elastic unloading is not needed prior to tracing the Yield Surface. The method is illustrated here by a few analyses, first for the simplest flow theory of plasticity, and Subsequently for crystal plasticity, using the Taylor model to represent a polycrystal.
