• Title/Summary/Keyword: 좌굴계수

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Fracture Prediction in Concrete-Filled Square HSS Bracing Members (콘크리트충전 각형 강관 가새부재의 파단 예측)

  • Lee, Mi-Ji;Moon, Ki-Hoon;Han, Snag-Whan
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.583-586
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    • 2011
  • 가새골조의 정확한 내진성능평가를 위해서는 실험과 유사한 이력거동과 파단 시점을 잘 예측할 수 있는 해석적 모델이 필요하다. 가새의 이력거동을 모사히기 위해 본 연구에서는 이전 연구자들에 의해 제안된 물리적 이론 모델을 사용하였다. 또한, 가새부재의 국부좌굴에 의한 파단 예측을 위해 피로변수의 보정계수를 도입한 손상 지표를 개선하였다. 결과적으로 실험과 해석 결과를 비교하여 콘크리트충전 각형 강관가새부재의 국부좌굴 효과를 반영한 피로 보정계수를 판폭두께비에 따라 회귀분석을 통해 결정하고, 본 연구에서 제안한 해석 모델의 결과와 이전 연구의 결과를 비교하여 검증하였다.

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Inelastic Buckling Analysis of Frames with Semi-Rigid Joints (부분강절 뼈대구조의 비탄성 좌굴해석)

  • Min, Byoung Cheol
    • Journal of Korean Society of Steel Construction
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    • v.26 no.3
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    • pp.143-154
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    • 2014
  • An improved method for evaluating effective buckling length of semi-rigid frame with inelastic behavior is newly proposed. Also, generalized exact tangential stiffness matrix with rotationally semi-rigid connections is adopted in previous studies. Therefore, the system buckling load of structure with inelastic behaviors can be exactly obtained by only one element per one straight member for inelastic problems. And the linearized elastic stiffness matrix and the geometric stiffness matrix of semi-rigid frame are utilized by taking into account 4th terms of taylor series from the exact tangent stiffness matrix. On the other hands, two inelastic analysis programs(M1, M2) are newly formulated. Where, M1 based on exact tangent stiffness matrix is programmed by iterative determinant search method and M2 is using linear algorithm with elastic and geometric matrices. Finally, in order to verify this present theory, various numerical examples are introduced and the effective buckling length of semi-rigid frames with inelastic materials are investigated.

Buckling Load Analysis of Spot-Welded Structures (점용접된 구조물의 좌굴하중해석)

  • 이현철;심재준;안성찬;한근조
    • Journal of Korean Port Research
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    • v.14 no.1
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    • pp.87-95
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    • 2000
  • This stability of a plate structure is very crucial problem which results in wrinkle and buckling. In this study, the effect of the pattern of spot-welding points of the two rectangular plates on the compressive and shear buckling load is studied with respect to the thickness, aspect ratio of plates and number of welding spots. Buckling coefficient of the plate not welded was compared with that of two plates with various thickness to extract the effect of thickness. The effect of number of welding spots are studied in two directions, longitudinal and transverse directions. The conclusions obtained were that the reinforcement effect was maximized when the aspect ratio was close to 1.75 at compressive load condition and that the effect of number of welding spots in transverse direction was larger than that in longitudinal direction at shearing load condition.

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Finite Element Analysis of the Shear Buckling Load with Respect to the Aspect Ratio and Number of Spots of two Rectangular Plates Spot-welded (점용접된 두 사각평판의 형상비 및 용접점수에 대한 전단좌굴하중의 유한요소해석)

  • 한근조;전형용;이현철
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.173-181
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    • 2000
  • The stability of a structural plate is a crucial problem which causes wrinkling and buckling. In this paper, the effect of the pattern of spot-welding points in the two rectangular plate on the shear buckling load is studied with respect to the thickness, the aspect ratio of plates, the number of welding spots. Buckling coefficient of the simple plate was compared with that of two plates with various conditions to extract the effect of buckling strength. The effect of the number of welding spots are studied in two directions, longitudinal and transverse directions. The concluded that the reinforcement effect was maximized when the aspect ratio was close to 1.5 and that the effect of number of welding spots in longitudinal direction was larger than that in transverse direction.

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Bucking Load Analysis of Spot-Welded Structures (점용접된 구조물의 좌굴하중해석)

  • 이현철;심재준;안성찬;한근조
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 1999.10a
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    • pp.265-272
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    • 1999
  • This stability of a plate structure is very crucial problem which results in wrinkle and bucking. In this study, the effect of the pattern of spot-welding points of the two rectangular plates on the compressive and shear bucking load is studied with respect to the thickness, aspect ratio of plates and number of welding spots. Buckling coefficient of the plate not welded was compared with that of two plates with various thickness to extract the effect of thickness. The effect of number of welding spots are studied in two directions, longitudinal and transverse directions. The conclusions obtained were that the reinforcement effect was maximized when the aspect ratio was close to 1.75 at compressive load condition and that the effect of number of welding spots in transverse direction was larger than that in longitudinal direction at shearing load condition.

A Study on the Evaluation of elastic buckling strength of Singly Symmetric I-Beams (일축대칭 I형보의 탄성좌굴강도 산정에 관한 연구)

  • Ku, So-Yeun;Ryu, Hyo-Jin;Lim, Nam-Hyoung;Lee, Jin-Ok
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.79-82
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    • 2008
  • The elastic critical moment of I-beams subjected to moment is directly affected by the following factors; loading type; loading position with respect to the mid-height of the cross section; end restraint conditions. Most design specifications usually provide buckling solutions derived for uniform moment loading condition and account for variable moment along the unbraced length with a moment gradient correction factor applied to these solutions. In order for the method in the SSRC Guide to be applicable for singly symmetric I-beams, improved moment gradient correction factors were proposed in this study. Finite element buckling analyses of singly symmetric I-beams subjected to transverse loading applied at different heights with respect to the mid-height of the cross section were conducted. Transverse loads consisting of a mid-span point load and a uniformly distributed load were considered in the investigation.

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Buckling Behaviors of Bucket Foundation for Offshore Wind Tower (해상풍력타워용 버켓기초의 좌굴거동)

  • Lee, Gye Hee;Tran, Duc Phu
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.25 no.3
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    • pp.123-127
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    • 2013
  • In this study, the buckling behaviors during the installation of a bucket foundation for an offshore wind turbine tower were investigated. The objective structure was modeled by using a commercial structural analysis program, and the buckling behavior of the model was estimated as Batdorf's parameter Z in the design code. The surrounding soil conditions and loading condition were applied to the verified analysis model. The effects of parameters such as the longitudinal stiffeners and driven depth were estimated for the buckling capacity. As a result, it was found that the longitudinal stiffeners could drastically increase the buckling capacity in a specific region. In addition, the buckling capacities increased linearly when considering the effect of the surrounding soil.

Characteristics of Smart Skin for Wireless LAN system under Buckling Load (무선 랜 시스템용 스마트 스킨의 좌굴 특성 연구)

  • 전지훈;유치상;황운봉;박현철;박위상
    • Composites Research
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    • v.14 no.2
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    • pp.43-49
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    • 2001
  • The characteristics of smart skin for wireless LAN system under compression load are investigated. The smart skin structure is composed of 3 layers of face material and 2 layers of core material. Theoretical formula for determining buckling load is derived by Rayleigh-Ritz method and compared with experimental result. The maximum length of specimen that buckling does not occur is determined by assuming that the compression load is sustained by only face material. In the experiment, if buckling occurs obviously then it follows the theoretical result well. In the process of buckling, the load supporting capability and the antenna property such as radiation pattern and reflection coefficient were examined.

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Post-buckling analysis using a load-displacement control (하중과 변위의 동시제어에 의한 좌굴후 현상해석)

  • Kwon, Y.D.;Lim, B.S.;Park, C.;Choi, J.M.
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.11
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    • pp.1931-1942
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    • 1997
  • A new load/displacement parameter method is developed for the cases that loads are applied to one or more points, and displacements of a structure are controlled at one or more points sinultaneously. The procedure exploits a generalized Riks method, which utilizes load/displacement parameters as scaling factors in order to analyze the post-buckling phenomena including snap-through or snap-back. A convergence characteristic is improved by employing new relaxation factors in incremental displacement parameter, particularly at the region where exhibits severe numerical instability. The improved performance is illustrated by means of numerical example.