• Title/Summary/Keyword: induced anisotropy

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Development of anisotropy in the hole punching process (홀 펀칭공정에서 이방성 발전에 관한 연구)

  • Yoon J. H.;Lee Y. S.;Kim S. S.;Kim E. Z.;Huh H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.287-290
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    • 2005
  • The shearing and punching processes are analyzed with the finite element method using an isotropic material model. The experimental result in the punching process shows that final radiuses of sheet metal according to the rolling direction and transverse direction are different because of the material anisotropy. The material anisotropy is induced by complicated large deformation in the polycrystalline aggregate. The contact region between the punch and sheet metal experiences severe deformation such as shear, compression and tension in the punching process. In this paper, the analysis of punching process for Al 1100 is performed with the ABAQUS Standard. The analysis of texture development and evolution is carried out based on the deformation history in the punching process. The deformation histories are extracted by UMAT in the ABAQUS Standard. The torture development is investigated with the pole figure and yield surface during the punching process.

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Characteristics of Shear Wave Velocity as Stress-induced and Inherent Anisotropies (응력유도 및 고유 이방성에 따른 전단파 속도 특성)

  • Lee, Chang-Ho;Yoon, Hyung-Koo;Truong, Hung-Quang;Cho, Tae-Hyeon;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.22 no.11
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    • pp.47-54
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    • 2006
  • Shear wave velocity of uncemented soil can be expressed as the function of effective stresses when capillary phenomena are negligible. However, the terms of effective stresses are divided into the direction of wave propagation and polarization because stress states are generally anisotropy. The shear wave velocities are affected by ${\alpha}$ parameters and ${\beta}$ exponents that are experimentally determined. The ${\beta}$ exponents are controlled by contact effects of particulate materials (sizes, shapes, and structures of particles) and the ${\alpha}$ parameters are changed by contact behaviors among particles, material properties of particles, and type of packing (i.e., void ratio and coordination number). In this study, consolidation tests are performed by using clay, mica and sand specimens. Shear wave velocities are measured during consolidation tests to investigate the stress-induced and inherent anisotropies by using bender elements. Results show the shear wave velocity depends on the stress-induced anisotropy for round particles. Furthermore, the shear wave velocity is dependent on particle alignment under the constant evvective stress. This study suggests that the shear wave velocity and the shear modulus should be carefully estimated and used for the design and construction of geotechnical structures.

Influence of Anisotropy of Microcrack Distribution in Pocheon Granite Rock on Elastic Resonance Characteristics (포천 화강암의 미세균열 분포 이방성이 탄성파 공진특성에 미치는 영향)

  • Kang, Tae-Ho;Kim, Kwang Yeom;Park, Deok-Won;Shin, Hyu-Soung
    • The Journal of Engineering Geology
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    • v.24 no.3
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    • pp.363-372
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    • 2014
  • Granite rock is reported to have three orthogonal anistoropic planes i.e., rift, grain induced by microcrack characteristics and mineral arrangement. We investigated the influence of thus fabric anisotropy in granite on elastic wave properties using free-free resonance test to obtain unconstrained compression wave velocity, shear velocity, Poisson ratio and damping ratio. As a result, Rod wave velocity is more dependent on anisotropy of granite due to microcrack distribution than shear wave velocity. In addition, anisotropy of Poisson ratio and damping ratio is also observed with respect to three anisotropic planes.

Anisotropy Angle Dependence of Interlayer Exchange Coupling of Perpendicular Magnetic [CoFe/Pt/CoFe]/IrMn Multilayers ([CoFe/Pt/CoFe]/IrMn 다층박막의 수직자기 이방성 각도에 따른 상호교환결합력 특성)

  • Lee, Sang-Suk;Choi, Jong-Gu;Hwang, Do-Guwn;Rhee, Jang-Roh
    • Journal of the Korean Magnetics Society
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    • v.18 no.6
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    • pp.232-236
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    • 2008
  • Dependence of interlayer exchange coupling on antiferromagnetic IrMn thickness, thermal stability, and parallel anisotropy angle in perpendicular anisotropy [CoFe/Pt/CoFe]/IrMn multilayers was investigated. The magnetic property of [CoFe($10{\AA}$)/Pt($8{\AA}$)/CoFe($10{\AA}$)] induced by antiferromagnetic ordering of IrMn layer was maintained a stable perpendicular anisotropy up to $250^{\circ}C$ and from $7{\AA}$ to $160{\AA}$ of IrMn thickness. The value of interlayer exchange coupling of [CoFe/Pt/CoFe]/IrMn multilayers with perpendicular anisotropy increased to 1.5 times at anisotropy angle of $60^{\circ}$ more than of $0^{\circ}$. On the other side, the interlayer exchange coupling at anisotropy angle of $90^{\circ}$ was $\infty$ Oe, it was likely diverted to a parallel shape magnetization.