Papers by Keyword: Anisotropy

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Authors: Jens Gibmeier, Manuela Klaus, Berthold Scholtes
Abstract: The deformation behavior of the magnesium base alloy AZ31 was studied by means of energy dispersive diffraction using high energy synchrotron radiation. The investigations were performed at the EDDI-beamline operated by the Hahn-Meitner-Institute at Bessy II, Berlin. In-situ stress analyses were carried out for samples subjected to purely elastic as well as elasto-plastic 4- point-bending. In addition reversely loaded states were investigated. The results impressively illustrate the potential of the energy dispersive diffraction analysis processed in transmission mode for residual stress analysis of challenging material states. Inhomogeneous loading and residual stress distributions with respect to the bending height of the prestressed bars were determined for the highly textured material state indicating different predominant deformation mechanisms during tensile loading and compressive loading, respectively. After load inversion also the predominant deformation mechanisms reverse.
Authors: Tsuyoshi Furushima, Tetsuro Masuda, Kenichi Manabe
Abstract: To understand the free surface roughening phenomena of polycrystalline metals, the surface roughening behaviors of three kinds of metal sheets were investigated under uniaxial tension. The materials used were AZ31 magnesium alloy, SPFC 590Y steel, and A5052-O aluminum alloy. In the in-situ observation of surface roughening for AZ31 magnesium alloy, it seemed that the surface of each grain roughened independently and the roughness increases with increasing plastic strain. In contrast to A5052-O and SPFC, the anisotropy of free surface roughening was observed for AZ31 magnesium alloy. Compared with planar anisotropy , the microscopic anisotropy of surface roughening is not related to . In AZ31 magnesium alloy, the anisotropy of surface roughening arises and, instead of the r-value, another parameter is needed to evaluate the anisotropy of free surface roughening.
Authors: N.Yu. Arutyunov, V.Yu. Trashchakov
Authors: Jun Feng Zhang, Tao Qi
Abstract: A 3D anisotropic elastoplastic-damage model was presented based on continuum damage mechanics theory. In this model, the tensor decomposition technique is employed. Combined with the plastic yield rule and damage evolution, the stress tensor in incremental format is obtained. The derivate eigenmodes in the proposed model are assumed to be related with the uniaxial behavior of the rock material. Each eigenmode has a corresponding damage variable due to the fact that damage is a function of the magnitude of the eigenstrain. Within an eigenmodes, different damage evolution can be used for tensile and compressive loadings. This model was also developed into finite element code in explicit format, and the code was integrated into the well-known computational environment ABAQUS using the ABAQUS/Explicit Solver. Numerical simulation of an uniaxial compressive test for a rock sample is used to examine the performance of the proposed model, and the progressive failure process of the rock sample is unveiled.
Authors: X. Xue, T.M. Liebling, A. Mocellin
Authors: Ming Jun Chen, Qi Long Pang, Jing He Wang, Kai Cheng
Abstract: 3Dfractal dimension and 2D profile fractal dimension distribution of the surfaces made by brittle or ductile grinding are calculated. From the calculated results of 3D fractal dimension, it can be found that the microtopograhpy of ductile ground surface is more exquisite than brittle ground surface and 3D fractal dimension Ds has inverse relation with the roughness parameter Rq. Through the analysis of 2D profile fractal dimension distribution in different ground surfaces, it is revealed that the topography of ground surface is changed with grinding parameters such as ground surfaces may have weakly or strongly anisotropic even isotropic features when different grinding parameters are adopted. Using fractal method to analyze the topography of ground surface is helpful to understand the generating mechanism of surface topography.
Authors: G.R. Canova, Yves Bréchet, L.B. Kubin, Benoit Devincre, Vassilis Pontikis, M. Condat
Authors: Qamar-ul Wahab, Hajime Kosugi, Hiroshi Yano, Christer Hallin, Tsunenobu Kimoto, Hiroyuki Matsunami
Authors: Temim Zribi, Ali Khalfallah, Hedi Belhadj Salah
Abstract: The present paper aims to assess the accuracy of identification methods used in the evaluation of the flow stress relationship of tubular materials for hydroforming applications. Based on experimental data acquired from home designed and manufactured experimental tool and results collected from literature, flow stress parameters are determined using both analytical and inverse identification methods. The obtained results are coped to experimental measurements to validate the proposed approaches. It is shown from the analysis based on the comparative assessment of flow stress inferred from tube bulge test that, inverse parameter identification method is the appropriate methodology that contribute to a more accurate tube hydroforming characterization.
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