• Title/Summary/Keyword: anisotropic

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Incorporation of anisotropic scattering into the method of characteristics

  • Rahman, Anisur;Lee, Deokjung
    • Nuclear Engineering and Technology
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    • v.54 no.9
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    • pp.3478-3487
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    • 2022
  • In this study, we incorporate an anisotropic scattering scheme involving spherical harmonics into the method of characteristics (MOC). The neutron transport solution in a light water reactor can be significantly improved because of the impact of an anisotropic scattering source with the MOC flat source approximation. Several problems are selected to verify the proposed scheme and investigate its effects and accuracy. The MOC anisotropic scattering source is based on the expansion of spherical harmonics with Legendre polynomial functions. The angular flux, scattering source, and cross section are expanded in terms of the surface spherical harmonics. Later, the polynomial is expanded to achieve the odd and even parity of the source components. Ultimately, the MOC angular and scalar fluxes are calculated from a combination of two sources. This paper presents various numerical examples that represent the hot and cold conditions of a reactor core with boron concentration, burnable absorbers, and control rod materials, with and without a reflector or baffle. Moreover, a small critical core problem is considered which involves significant neutron leakage at room temperature. We demonstrate that an anisotropic scattering source significantly improves solution accuracy for the small core high-leakage problem, as well as for practical large core analyses.

A New Yield Function for Voided Materials (보이드 재료에 대한 새로운 항복함수의 제안)

  • 김성태
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.04a
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    • pp.13-16
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    • 2000
  • In this paper the authors proposed a new anisotropic yield criterion for porous ductile materials. By using the proposed yield criterion and its flow rules a damage evolution of anisotropic sheet under biaxial tensile loading is investigated. A comparison of yield locus and damage evolution between the proposed yield criterion and experiments are carried out. the results are in good agreement.

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Buckling Analysis of Anisotropic Laminated Plates with Shear Deformation (전단변형을 고려한 이방성 적층판의 좌굴해석)

  • 최용희;권택진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.361-368
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    • 2001
  • This paper deals with the buckling load of antisymmetric angle-ply and cross-ply laminated rectangular plates. Buckling analysis is preformed for a simply supported, shear deformable laminated plate subjected to uniaxial compression and biaxial compression combined with uniform lateral pression. The shear deformation theory is considered to figure out a more exact behavior of laminated plates exactly. The purposes of this study are to formulate anisotropic laminated plates with shear deformation and to investigate the buckling load according to the various variables of laminated plates by using the exact solutions for anisotropic laminated plates having simply supported boundary.

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Dyadic Green`s Function for an Unbounded Anisotropic Medium in Cylindrical Coordinates

  • Kai Li;Park, Seong-Ook;Pan, Wei-Yan
    • Journal of electromagnetic engineering and science
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    • v.1 no.1
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    • pp.54-59
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    • 2001
  • The dyadic Green`s function for an unbounded anisotropic medium is treated analytically in the Fourier domain. The Green`s function, which is expressed as a triple Fourier integral, can be next reduced to a double integral by performing the integral, by performing the integration over the longitudinal Fourier variable or the transverse Fourier variable. The singular behavior of Green`s is discussed for the general anisotropic case.

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A Study on Determination of Stress Intensity Factor of Orthotropic Plates Using Crack Tip Singular Element (균열선단 특이요소를 이용한 직교이방성판의 응력확대계수 결정에 관한 연구)

  • 진치섭;최현태;이홍주
    • Proceedings of the Korea Concrete Institute Conference
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    • 1991.10a
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    • pp.124-128
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    • 1991
  • Wood, laminates, reinforced concrete, and some special types of metals systems with controlled grain orientation are often orthotropic and at least rectilinearly anisotropic from point to point, if regarded as homogeneous media. Orthotropic bodies where a crack is not associated with a plane of elastic symmetry may be conveniently treated as a crack problem in a generally anisotropic body. At this work, approach for the determination of the stress intensity factors (SIF) of anisotropic body using crack tip singular elements is presented. Caculated values are in good agreement with the others.

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Formulation and Identification of an Anisotropic Constitutive Model for Describing the Sintering of Stainless Steel Powder Compacts

  • Vagnon, Alexandre;Bouvardb, Didier.;Kapelskic, Georges
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.64-65
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    • 2006
  • Anisotropic constitutive equations for sintering of metal powder compacts have been formulated from a linear viscous transversely-isotropic model in which an anisotropic sintering stress has been introduced to describe free sintering densification kinetics. The identification of material parameters defined in the model, has been achieved from thermomechanical experiments performed on 316L stainless steel warm-compacted powder in a dilatometer allowing controlled compressive loading.

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Anisotropic Variable Herz Spaces and Applications

  • Aissa Djeriou;Rabah Heraiz
    • Kyungpook Mathematical Journal
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    • v.64 no.2
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    • pp.245-260
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    • 2024
  • In this study, we establish some new characterizations for a class of anisotropic Herz spaces in which all exponents are considered as variables. We also provide a description of these spaces based on bloc decomposition. As an application, we investigate the boundedness of certain sublinear operators within these function spaces.

A study on Stress Singularities for V-notched Cracks in Anisotropic and/or Pseudo-isotropic Dissimilar Materials

  • Cho, Sang-Bong;Kim, Jin-kwang
    • International Journal of Precision Engineering and Manufacturing
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    • v.3 no.2
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    • pp.22-32
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    • 2002
  • V-notched crack problems can be formulated as eigenvalue problems. The problem ova v-notched crack in anisotropic and/or pseudo-isotropic dissimilar materials was formulated as an eigenvalue problem to discuss stress singularities. The eigenvalue problem was served by the commercial numerical program; MATHEMATICA. The specific data of eigenvalues possessing the stress singularity were obtained. Stress singularities fur v-notched cracks in anisotropic and/or pseudo-isotropic dissimilar materials were discussed according to the relation between wedge angle and material property. It was shown that there are three cases of eigenvalues possessing the stress singularity; one real, two real and one complex.

A Theoretical Study for the Thermal Conductivity Measurement of Anisotropic Material using Photothermal Deflection Spectroscopy (광열편향법을 이용한 이방성 재료의 열전도계수 측정에 관한 이론적 연구)

  • Jeon, Pil-Soo;Yoo, Jai-Suk;Kim, Hyun-Jung
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2465-2470
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    • 2007
  • We have analyzed the three-dimensional thermal conduction in anisotropic materials using nonsymmetric-Fourier transforms. And a complete theoretical treatment of the photothermal deflection spectroscopy has been performed for thermal conductivity measurement in anisotropic medium. Thermal conductivity tensor was determined by the deflection angle and phase angle with the relative position between the heating and probe beams. The influence of the parameters, such as modulation frequency of the heating beam, the thermal conductivity tensor, was investigated.

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Prediction of the Critical Stress for the Inclined Crack in Orthotropic Materials under Biaxial load (2축하중을 받는 직교이방성 경사균열에서 임계응력의 예측)

  • Lim, Won-Kyun;Cho, Hyung-Suk;Jeong, Woo-Kil;Lee, Ill-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.11 s.254
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    • pp.1384-1391
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    • 2006
  • The problem of an infinite anisotropic material with a crack inclined with respect to the principal material axes is analyzed. The material is subjected to uniform biaxial load along its boundary. It is assumed that the material is homogeneous, but anisotropic. By considering the effect of the horizontal load, the distribution of stresses at the crack tip is analyzed. The problem of predicting critical stress in anisotropic solids which is a subject of considerable practical importance is examined and the effect of load biaxiality is made explicitly. The present results based on the normal stress ratio theory show significant effects of biaxial load, crack inclination angle and fiber orientation on the critical stress. The analysis is performed for a wide range of the crack angles and biaxial loads.