• 제목/요약/키워드: uniaxial anisotropy

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서울화강암의 암석강도 측정치의 비교 평가 연구 (A Study on Comparison and Evaluation of various Strength in Seoul Granite)

  • 윤지선;김두영;정흥모
    • 터널과지하공간
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    • 제5권2호
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    • pp.144-154
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    • 1995
  • In this paper, we make a study on comparison and evaluation of the seoul granite properties, which are unit weight, uniaxial compressive strength, Brazilian tensile strength and, point load strength. The typical result are as follow- 1. From the measured value of point load strength anisotropy index, the seoul granite is considered to be homogeneous. 2. There is a linear relationship between uniaxial compressive strength and size corrected point load strength index. 3. Brazilian tensile strength and size corrected point load strength index are closely tied together.

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압연강판의 이방성에 관한 연구 (Study of anisoptopy of sheet metals)

  • 인정제
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 춘계학술대회논문집
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    • pp.153.1-156
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    • 1999
  • Based upon the experimental data from multi-stage tensile loading at angles to the rolling direction of steel sheets, anisotropic hardening rules are proposed. Experiments show that orthotropic anisotropy is maintained and the orientations of orthotropy axes are changed during tensile loading. A phenomenological model is proposed which includes the rotations of orthotropy axes, work hardening and kinematic hardening. Using the model, uniaxial tensile stress, R-value and tensile necking strain are predicted and compared with the experimental data.

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새 자성재료의 기초자기특성 연구(2) - 펄스측정법에 의한 비정질 $Fe_{80}B_{15}Si_{5}$ 합금의 자기특성 (Study on Basic Magnetic Characteristics in New Magnetic Materials(2) - Magnetic Properties of Amorphous $Fe_{80}B_{15}Si_{5}$ alloy Measures with Pulse Method)

  • 이용호;신용돌;김인수;이연숙;노태환;강일구
    • 한국자기학회지
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    • 제1권2호
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    • pp.42-48
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    • 1991
  • 대표적인 철계비정질 합금인 $Fe_{80}B_{15}Si_{5}$의 기초연자기특성을 펄스법으로 측정하였다. 자기변형, 이방성에너지, 자화율의 역수들 사이의 정량적 관계를 연구하였다. 자기변형과 일축이방성에너지의 자화율의 역수에 대한 상대적인 기여도를 계산하였다. 내부응력의 크기와 듀도이방성에너지를 추산하였다. 시료의 장축방향으로 인가된 장력은 유도 이방성에너지를 크게 증가하게 함을 알았다.

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ANISOTROPY CONSTANTS OF $(Sm_{0.5}RE_{0.5})Fe_{11}Ti$ COMPOUNDS (RE=RARE EARTH)

  • Kim, H.T.;Kim, Y.B.;Park, W.S.;Kim, C.S.;Kim, T.K.;Jin, Han-Min
    • 한국자기학회지
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    • 제5권5호
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    • pp.683-686
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    • 1995
  • Using by the x-ray diffractometry(XRD), the thermomagnetic analysis(TMA), a scanning electron microscopy (SEM-EDX), we knew that the $(Sm_{0.5}RE_{0.5})Fe_{11}Ti$ (RE=Ce,Pr,Nd,Sm,Gd,Tb) compounds were formed to tetragonal $ThMn_{12}$-type structure having a uniaxial magnetocrystalline anisotropy with easy magnetization c-axis. The intrinsic magnetic properties of those were determined by fitting the two magnetization curves of experimental and calculation magnetization. The anisotropy constant $K_{1}$ of this compounds was in the range of $1.75\;-\;9.2\;MJ/m^{3}$ and approximately one order higher than $K_{2}$. $SmFe_{11}Ti$ had the highest anisotropy of $K_{1}\;=\;9.2\;MJ/m^{3}$, $K_{2}\;=\;0.4\;MJ/m^{3}$ and ${\mu}_{o}H_{A}=\;19.8\;T$ among the compounds, substitution of any other rare earth elements for Sm decreased magnetocrystalline anisotropy.

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평면이방성 알루미늄 재료의 귀발생 예측에 있어서 항복함수와 초기 Back-Stress의 영향 (Influence of yield functions and initial back stress on the earing prediction of drawn cups for planar anisotropic aluminum alloys)

  • 윤정환;;정관수;양동열;장성기
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1998년도 춘계학술대회논문집
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    • pp.58-61
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    • 1998
  • Anisotropy is closely related to the formability of sheet metal and should be considered carefully for more realistic analysis of actual sheet metal forming operations. In order to better describe anisotropic plastic properties of aluminum alloy sheets, a planar anisotropic yield function which accounts for the anisotropy of uniaxial yield stresses and strain rate ratios simultaneously was proposed recently[1]. This yield function was used in the finite element simulations of cup drawing tests for an aluminum alloy 2008-T4. Isotropic hardening with a fixed initial back stress based on experimental tensile and compressive test results was assumed in the simulation. The computation results were in very good agreement with the experimental results. It was shown that the initial back stress as well as the yield surface shape have a large influence on the prediction of the cup height profile.

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Magnetic Properties of Strained L10-ordered FePt and CoPt: An ab initio Study

  • Choi, Heechae
    • Applied Science and Convergence Technology
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    • 제23권5호
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    • pp.273-278
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    • 2014
  • Using ab initio calculations, the effects of uniaxial, biaxial, and hydrostatic strains on the magnetocrystalline anisotropy of $L1_0$-orderd FePt and CoPt alloys were systematically investigated. Interestingly, the rates and the signs of magnetocrystalline anisotropy changes of FePt and CoPt were determined by the directions and dimensions of strains. The calculation results are consistent with the previous experimental observations and are expected to provide directions to tailor magnetic properties of various types of $L1_0$-ordered FePt and CoPt systems.

소형펀치 시험법을 이용한 Al 2024 ECAP 재료의 강도특성 평가 (Assessment of Strength Characteristics of Al 2024 ECAP Metal Using Small Punch Testing)

  • 마영화;최정우;김선화;윤기봉
    • 대한기계학회논문집A
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    • 제30권1호
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    • pp.8-17
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    • 2006
  • When subjected to severe shear deformation by ECAP, microstructure of Al2024 becomes extremely refined. To measure the strength of that, small punch(SP) testing method was adopted as a substitute for the conventional uniaxial tensile testing because the size of material processed by ECAP were limited to ${\psi}12\;mm$ in transverse direction. SP tests were performed with specimens in longitudinal and transverse directions of Al2024 ECAP metal. For comparing the strength values with those assessed by SP tests, uniaxial tensile tests were also conducted with specimens in longitudinal direction. Failure surfaces of the tested SP specimens showed that failure mode was shear deformation and Al 2024 ECAP metal has an anisotropy in strength. Thus, conventional equations proposed for assessing the strength characteristics were improper to assess those of Al2024 ECAP metal. In this paper a way of assessing the strength of Al 2024 ECAP metal was proposed and was proven to be effective.