• Title/Summary/Keyword: Critical thickness

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Reconstruction of Postburn Nasal Alar Defect by Paramedian Forehead Flap (화상으로 손실된 비익에 대한 전두피판을 이용한 재건)

  • Park, Daehwan;Park, Sulki;Baik, Bongsoo;Ji, Soyoung
    • Journal of the Korean Burn Society
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    • v.24 no.2
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    • pp.60-63
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    • 2021
  • In the face, the nose plays an important role in both function and appearance. Among the subunits on the nose, the alar is a critical nasal structure of high aesthetic value. Previously, many surgeons have insisted that structural support should be added to the reconstruction of alar and particularly so in the case of a full-thickness defect. In a 58-year-old male patient who had a third-degree burn injury and full-thickness defect in most of the left nasal alar, forehead flap surgery alone was successfully performed without structural support.

Analysis of normal Bone propagation characteristics in a high-temperature superconducting tape (고온 초전도체 테이프의 상전도 영역 전파 특성 해석)

  • 정신근;설승윤
    • Progress in Superconductivity and Cryogenics
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    • v.3 no.1
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    • pp.11-15
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    • 2001
  • Stability of a Bi-2223/Ag tape was studied by using a numerical model considering the temperature distribution of cross-sectional area. The dynamic evolution of normal zone of a HTS tape can be shown by the developed two-dimensional Program using finite difference method. Two kinds of analyses are compared to quantify the critical disturbance energy for quenching HTS tapes. One is the length-thickness(x-r) side and the other is the length-width(x-z) side. For each case. the governing energy balance equations and corresponding boundary conditions are formulated. The results of analyses shows that the critical disturbance energies for each cases seem to be very close for considered Bi-2223/Ag tape .

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Buckling of non-homogeneous orthotropic conical shells subjected to combined load

  • Sofiyev, A.H.;Kuruoglu, N.
    • Steel and Composite Structures
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    • v.19 no.1
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    • pp.1-19
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    • 2015
  • The buckling analysis is presented for non-homogeneous (NH) orthotropic truncated conical shells subjected to combined loading of axial compression and external pressure. The governing equations have been obtained for the non-homogeneous orthotropic truncated conical shell, the material properties of which vary continuously in the thickness direction. By applying Superposition and Galerkin methods to the governing equations, the expressions for critical loads (axial, lateral, hydrostatic and combined) of non-homogeneous orthotropic truncated conical shells with simply supported boundary conditions are obtained. The results are verified by comparing the obtained values with those in the existing literature. Finally, the effects of non-homogeneity, material orthotropy, cone semi-vertex angle and other geometrical parameters on the values of the critical combined load have been studied.

Ultimate Uplift Capacity of Circular Anchors in Layered Soil

  • Shin, Eun-Chul;Das, Braja-M
    • Geotechnical Engineering
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    • v.14 no.3
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    • pp.63-72
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    • 1998
  • Laboratory model test results for ultimate uplift capacity of horizontal circular anchors embedded in soft clay overlain by dense sand are presented. The effect of the critical embedment ratio on the thickness of the clay layer was evalyated. An approximate preocedure for estimating the net ultimate capacity is presented.

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Study on commercialization process of Bi-B223 HTS tape (Bi-2223 고온초전도 선의 상용화 공정 연구)

  • 하동우;김상철;오상수;하홍수;이동훈;양주생;황선역
    • Progress in Superconductivity and Cryogenics
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    • v.6 no.1
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    • pp.1-5
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    • 2004
  • Long length of Bi-2223/Ag superconducting wives were fabricated by stacking and drawing process with advanced heat-treatment schedules. Intermediate annealing was carried out to increase the homogeneity and uniformity of the superconducting filaments embedded in the silver matrix. Phase modification from tetragonal to orthorhombic Bi-2212 by pre heat treatment(PHT) was executed to improve the texture and phase transformation of Bi-2223. Drawing stress was measured to predict the sausaging and stress limit. Rolling Parameters such as thickness. width and winding tension were investigated to roll the tape with uniformity. 1 km length of Bi-2223/Ag superconducting wires were fabricated without any breakage. Critical current (Je) of 270 m length of superconducting tapes was measured over than $70 A/cm^2$ continuously after final sintering.

Numerical investigations on the turbulence driven responses of a plate in the subcritical frequency range

  • De Rosa, S.;Franco, F.;Gaudino, D.
    • Wind and Structures
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    • v.15 no.3
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    • pp.247-261
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    • 2012
  • Some numerical investigations are presented concerning the response of a given plate under turbulence driven excitations. Three different input loads are simulated according to the wall pressure distributions derived from the models proposed by Corcos, Efimtsov and Chase, respectively. Modal solutions (finite element based) are used for building the modal stochastic responses in the sub-critical aerodynamic frequency range. The parametric investigations concern two different values of the structural damping and three values of the boundary layer thickness. A final comparison with available experimental data is also discussed. The results demonstrate that the selection of the adequate TBL input model is still the most critical step in order to get a good prediction.

Buckling characteristics and static studies of multilayered magneto-electro-elastic plate

  • Kiran, M.C.;Kattimani, S.C.
    • Structural Engineering and Mechanics
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    • v.64 no.6
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    • pp.751-763
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    • 2017
  • This article deals with the buckling behaviour of multilayered magneto-electro-elastic (MEE) plate subjected to uniaxial and biaxial compressive (in-plane) loads. The constitutive equations of MEE material are used to derive a finite element (FE) formulation involving the coupling between electric, magnetic and elastic fields. The displacement field corresponding to first order shear deformation theory (FSDT) has been employed. The in-plane stress distribution within the MEE plate existing due to the enacted force is considered to be equivalent to the applied in-plane compressive load in the pre-buckling range. The same stress distribution is used to derive the potential energy functional. The non-dimensional critical buckling load is accomplished from the solution of allied linear eigenvalue problem. Influence of stacking sequence, span to thickness ratio, aspect ratio, load factor and boundary condition on critical buckling load and their corresponding mode shape is investigated. In addition, static deflection of MEE plate under the sinusoidal and the uniformly distributed load has been studied for different stacking sequences and boundary conditions.

Surface effects on vibration and buckling behavior of embedded nanoarches

  • Ebrahimi, Farzad;Daman, Mohsen;Fardshad, Ramin Ebrahimi
    • Structural Engineering and Mechanics
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    • v.64 no.1
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    • pp.1-10
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    • 2017
  • The present paper deals with the free vibration and buckling problem with consideration of surface properties of circular nanobeams and nanoarches. The Gurtin-Murdach theory is used for investigating the surface effects parameters including surface tension, surface density and surface elasticity. Both linear and nonlinear elastic foundation effect are considered on the circular curved nanobeam. The analytically Navier solution is employed to solve the governing equations. It is obviously detected that the natural frequencies of a curved nanobeams is substantially influenced by the elastic foundations. Besides, it is revealed that by increasing the thickness of curved nanobeam, the influence of surface properties and elastic foundations reduce to vanished, and the natural frequency and critical buckling load turns into to the corresponding classical values.

Fatigue Life Prediction for Resistance Spot Weldment of Aluminum Alloy Sheet (알루미늄 합금판 저항 점용접부의 피로수명 예측)

  • 장건익;안병국;김동건
    • Journal of Welding and Joining
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    • v.20 no.2
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    • pp.116-124
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    • 2002
  • The fatigue life is predicted on tensile-shear spot weldment made from Al-Mg alloy sheet with thickness of 0.8mm using Mitchell's method and uniform material law by $B{\ddot{a}}umel$ and Seeger based on local strain approach. The fatigue properties of critical HAZ region are estimated from the tensile property using simple hardness method. To predict the fatigue life of spot weldment, the local stresses and strains at the potential critical region are estimated by Neuber's rule. The predicted fatigue life based on uniform material law using HAZ's material properties provides good results within a factor of 3, conservatively.

Buckling and Limit Width-Thickness Ratios of Steel Columns under Compression at Elevated Temperatures (온도 상승에 따른 압축강재의 좌굴 및 한계 판폭두께비)

  • Kang, Seong-Deok;Kim, Jae-Uk;Choi, Hyun-Sik
    • Journal of Korean Association for Spatial Structures
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    • v.12 no.3
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    • pp.55-62
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    • 2012
  • 본 연구는 온도 증가에 따른 압축을 받는 H형 강재의 플랜지와 웨브의 국부 및 전체좌굴응력 내화해석 프로그램 개발과 플랜지와 웨브가 항복파괴전에 국부좌굴이 일어나지 않을 한계 판폭두께비의 상관값을 구하는 프로그램을 개발하는 것이다. 고온에서의 강재의 응력-변형도 관계식은 EC3:Part 1.2를 근거로 하였으며, 비교, 검토를 위하여 영국 BS5950의 강재를 대상으로 온도 증가에 따른 압축을 받는 강재의 플랜지와 웨브의 파괴온도와 하중을 본 연구의 내화해석 프로그램으로 예측하였다. 본 연구는 좌굴 및 항복에 대한 내화해석 프로그램을 개발하는 것을 목적으로 하고 적용 예를 통하여 좌굴 및 한계 판폭두께비를 분석하고 개발 프로그램의 타당성을 검토하였다.