• Title/Summary/Keyword: Order of Singularity

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Boundary Element Analysis of Singular Stresses in a Viscoelastic Thin Film due to Moisture Absorption (수분 흡수로 인해 점탄성 필름에 발생하는 특이 응력의 경계요소해석)

  • Lee, Sang-Sun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.3 s.174
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    • pp.685-690
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    • 2000
  • This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate as the film absorbs moisture from the ambient environment. Th e time domain boundary element method is employed to investigate the behavior of interface stresses. The order of the free-edge singularity is obtained numerically for a given viscoelastic model. It is shown that the stress singularity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model considered.

Viscoelastic Stress Analysis of Polymeric Thin Layer Under Moisture Absorption (수분 흡수로 인해 고분자 박막에서 발생하는 점탄성 응력 해석)

  • 이상순;장영철
    • Journal of the Microelectronics and Packaging Society
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    • v.10 no.1
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    • pp.25-29
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    • 2003
  • This paper deals with the stress singularity induced at the interface corner between the elastic substrate and the viscoelastic thin film as the polymeric film absorbs moisture from the ambient environment. The boundary element method is employed to investigate the behavior of interface stresses. The order of the singularity is obtained numerically for a given viscoelastic model. It is shown that the stress singularity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model considered.

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Stress Singularity Behaviour in the Frictional Complete Contact Problem of Three Bodies (세 물체 간 마찰 완전 접촉 문제의 응력 특이성 거동)

  • Kim, Hyung-Kyu
    • Tribology and Lubricants
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    • v.35 no.4
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    • pp.229-236
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    • 2019
  • This study investigates the stress singularity that occurs at the contact edge of three bodies in a frictional complete contact. We use the asymptotic analysis method, wherein we constitute an eigenvalue problem and observe the eigenvalue behavior, which we use to obtain the order of the stress singularity. For the present geometry of three bodies in contact, a contact between a cracked indenter and half plane is considered. This is a typical geometry of the PCMI problem of a nuclear fuel rod. Thus, this paper, specifically presents the characteristics of the PCMI problem from the perspective of stress singularity. Consequently, it is noted that the behavior of the stress singularity varies with the difference in the crack angle, coefficient of friction, and material dissimilarity, as is observed in a frictional complete contact of two bodies. In addition, we find that the stress singularity changes essentially linearly with respect to the coefficient of friction, regardless of the variation in the crack angle and material dissimilarity. Concurrently, we find the order of singularity to be 0.5 at a certain coefficient of friction, irrespective of the crack angle, which we also observe in the crack problem of a homogeneous and isotropic body. The order of singularity can also exceed 0.5 in the frictional complete contact problem of three bodies. This implies that the propensity for failure when three bodies are in frictional complete contact can be even worse than that in case of a failure induced by a crack.

Analysis of Moisture Stresses Induced in Polymeric Thin Film (고분자 박막에서 발생하는 수분응력 해석)

  • 이상순
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2002.11a
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    • pp.137-142
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    • 2002
  • This paper deals with the stress singularity induced at the interface corner between the elastic substrate and the viscoelastic thin film as the polymeric film absorbs moisture from the ambient environment. The boundary element method is employed to investigate the behavior of Interface stresses. The order of the singularity is obtained numerically for a given viscoelastic model. It is shown that the stress singularity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model considered.

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SINGULARITY ORDER OF THE RIESZ-NÁGY-TAKÁCS FUNCTION

  • Baek, In-Soo
    • Communications of the Korean Mathematical Society
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    • v.30 no.1
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    • pp.7-21
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    • 2015
  • We give the characterization of H$\ddot{o}$lder differentiability points and non-differentiability points of the Riesz-N$\acute{a}$gy-Tak$\acute{a}$cs (RNT) singular function ${\Psi}_{a,p}$ satisfying ${\Psi}_{a,p}(a)=p$. It generalizes recent multifractal and metric number theoretical results associated with the RNT function. Besides, we classify the singular functions using the singularity order deduced from the H$\ddot{o}$lder derivative giving the information that a strictly increasing smooth function having a positive derivative Lebesgue almost everywhere has the singularity order 1 and the RNT function ${\Psi}_{a,p}$ has the singularity order $g(a,p)=\frac{a{\log}p+(1-a){\log}(1-p)}{a{\log}a+(1-a){\log}(1-a)}{\geq}1$.

Analysis of Stresses Induced in a Polymer Coating Layer due to Temperature Change (온도변화에 대한 고분자 코팅 층에 발생하는 응력 해석)

  • 박명규;이상순;서창민
    • Journal of Ocean Engineering and Technology
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    • v.17 no.6
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    • pp.72-76
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    • 2003
  • This paper deals with the stress singularity developed in a polymer layer that is coated to a concrete surface, due to temperature change. The boundary element method is employed to investigate the behavior of interface stresses. The polymeric layer is assumed to be a linear viscoelastic material, and is thermorheologically simple. The order of the singularity is obtained, numerically, for a given viscoelastic model. Numerical results exhibit the relaxation of interface stresses, and large gradients are observed in the vicinity of the free surface. Results show that the stress singularity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model.

Analysis of Thermal Stresses Developed in Bonding Interface of Semiconductor Chip (반도체 칩의 접착계면에 발생하는 열응력 해석)

  • 이상순
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.10a
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    • pp.437-443
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    • 1999
  • This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate subjected to uniform temperature change. The viscoelastic film has been assumed to be thermorheologically simple. The time-domain boundary element method(BEM) has been employed to investigate the behavior of interface stresses. The order of the free-edge singularity has been obtained numerically for a given viscoelastic model. It is shown that the free-edge stress intensity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model considered.

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Boundary Element Analysis of Interface Stresses in a Thin Film Due to Moisture Absorption (수분 흡수로 인해 얇은 필름에 발생하는 계면 응력의 경계요소해석)

  • 이상순
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.04a
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    • pp.19-26
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    • 1999
  • This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate as the film absorbs moisture from the ambient environment. The rime-domain boundary element method is employed to investigate the behavior of interface stresses. The order of the free-edge singularity is obtained numerically for a given viscoelastic model. It is shown that the free-edge stress intensity factor is relaxed with time,'while the order of the singularity increases with time for the viscoelastic model considered.

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A 2-D four-noded finite element containing a singularity of order λ

  • Abdel Wahab, M.M.;de Roeck, G.
    • Structural Engineering and Mechanics
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    • v.3 no.4
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    • pp.383-390
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    • 1995
  • A 2-D four-noded finite element which contains a ${\lambda}$ singularity is developed. The new element is compatible with quadratic standard isoparametric elements. The element is tested on two different examples. In the first example, an edge crack problem is analyzed using two different meshes and different integration orders. The second example is a crack perpendicular to the interface problem which is solved for different material properties and in turn different singularity order ${\lambda}$. The results of those examples illustrate the efficiency of the proposed element.

Numerical Simulation of Hybrid Polarization Singularity Configurations

  • Ye, Dong;Peng, Xinyu;Zhou, Muchun;Song, Minmin
    • Current Optics and Photonics
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    • v.1 no.4
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    • pp.396-401
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    • 2017
  • In this article, we proposed hybrid polarization singularity configurations, based on the superposition of two orthogonal circularly polarized components, one of which is a light beam with two optical vortices. The topological configurations are the hybridization of lowest-order polarization singularities, but are different from high-order polarization singularities. Our numerical simulation may provide a theoretical basis for expanding the variety of polarization singularity configuration.