• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.11-20
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• 2014

This paper aims at comparing and analyzing shear buckling characteristics between sinusoidal corrugation shape and trapezoidal one. For this, I adopted the equal-length trapezoidal corrugation and sinusoidal one for the analytical models, and analyzed their shear buckling characteristics through linear buckling analysis and on its theory. Generally, the shear buckling shapes of corrugated steel plates are classified into local buckling, global buckling, and interactive buckling from the two buckling modes. Sinusoidal corrugation shape, unlike trapezoidal corrugation, does not have flat sides, which causes another tendency in shear buckling mode. Especially, the changes and different aspects of shear buckling on the boundary between local buckling and global buckling appear in different corrugation shapes. According to the analysis results, interactive buckling mode appeared on the boundary of local buckling and global bucking in trapezoidal corrugation. However, in the case of corrugated steel plates with sinusoidal configuration, interactive buckling mode appeared in the part where global bucking takes place. Besides, trapezoidal shapes are of advantages on shear buckling resistance in the local buckling section, and so are sinusoidal shapes in the global buckling section.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.535-543
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• 2002

The purpose of this paper is to investigate the slenderness ratio effect on buckling characteristics of thin cylindrical structures subjecting the shear loads in detail. To do this, the buckling strength evaluations were carried out with using the evaluation formulae proposed by J. Okada. From the results of the buckling strength evaluations, the three types of staled cylindrical test specimen, which have L/R=3.1, 1.6, and 1.0, are determined for the numerical analyses and tests. From results, target slenderness ratio over L/R=3 results in dominant bending buckling mode, smaller slenderness ratio under L/R=1 results in dominant shear buckling mode, and near L/R=1.6 region shows the mixed buckling mode which has the bending and shear buckling mode simultaneously. Most results of buckling characteristics obtained by the numerical analyses and the evaluation formulae we in good agreement with those of tests.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.185-185
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• 2011

기존 장대레일 궤도의 안정성 평가는 궤도 매개변수에 대하여 고정된 안전측의 값을 사용하는 결정론적인 해석에 의존해서 평가되어져 왔다. 그러나 실제현장의 궤도조건은 많은 영향인자들에 의해 그 특성이 불확실하게 변하고 있다. 따라서 온도하중에 의한 궤도 좌굴에 영향을 미치는 궤도 구성인자들의 불확실성 및 임의성을 보다 합리적으로 고려하기 위해서 확률론적 기법을 적용하는 것이 필수적이다. 본 연구에서는 기존 본 연구진에 의해 개발된 장대레일 궤도의 좌굴확률 평가시스템을 이용하여 좌굴 취약도 곡선을 나타내었으며, 궤도 좌굴에 영향을 미치는 주요변수 중 하나인 도상횡저항력에 대한 영향을 분석하였다. 좌굴확률 평가시스템에서는 장대레일 궤도의 좌굴확률을 산정하기 위하여 구조물의 안정과 파괴를 판단할 수 있는 기준을 한계상태방정식으로 표현하고, 이 한계상태방정식으로부터 확률론적 기법 중 하나인 AFOSM(Advanced First Order Second Moment) 방법을 이용하여 파괴확률의 간접적인 지표인 신뢰도지수(${\beta}$)를 통해 좌굴확률을 계산한다. 한계상태방정식에서 구조물의 강도(보유성능)에 해당하는 부분은 궤도의 허용좌굴온도이고, 하중(요구성능)에 해당하는 부분은 레일온도하중으로써 현재 레일온도와 중립온도의 차로 반영된다. 허용좌굴온도 산정에 고려되는 주요변수는 곡선반경(Radius), 도상횡저항력(Lateral Ballast Resista nce), 연직도상강성(Vertical Ballast Stiffness), 궤도 틀림량(Misalignment), 틀림길이(Half Wave Length), 열차운행속도(Velocity)이다. 각 확률변수들이 갖는 확률분포는 모두 정규분포로 가정하였다. 궤도의 기하학적 특성은 곡선반경 5,000m에 대해 고려하였으며, 열차는 KTX의 제원을 사용하여 정지된 상태에서 고려하였다. 틀림량과 틀림길이는 이에 대한 통계적 특성자료가 부족하여 확률변수로 고려하지 않고 결정론적 값으로 취급하였다. 레일온도의 통계적 특성치는 본 연구진에 의해 구축된 기후요소 및 레일온도 DB를 근거로 결정하였으며, 중립온도는 선로관리지침에 따라 $25{\pm}3^{\circ}C$를 기준으로 결정하였다. 또한 도상횡저항력은 실측 데이터를 참고로 하여 평균값에서 10%의 변동량을 갖는 것으로 보고 통계적 특성치를 결정하였다. 도상횡저항력이 좌굴확률에 미치는 영향을 매우 큰 것을 알 수 있었으며, 레일온도 $60^{\circ}C$일 때 도상횡저항력이 증가하면서 감소되는 좌굴확률이 도상저항력이 커질수록 그 감소량이 작아지는 것을 알 수 있었다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.336-339
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• 2011

본 논문에서는 유한요소 프로그램 (ANSYS)을 이용하여 돔격납철판 (dome containment liner plate)의 양중시 좌굴특성의 연구를 수행하였다. 원전 격납철판의 양중시, 양중 와이어(wire)의 구조적인 배치특성상 격납철판에 압축력이 유발되고, 이러한 압축력은 격납철판의 좌굴을 일으킬 수 있다. 다양한 양중인자 (lifting factors)를 고려한 격납철판 유한요소모델을 수립하고, 이러한 양중인자들의 좌굴특성에 미치는 영향을 고찰하였다. 양중 와이어의 체결위치의 높이가 낮을 수록 좌굴강도가 증가하며, 라이너 플레이트 두께에 비례하여 좌굴강도가 증가하였다.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.323-332
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• 1997

This study is aimed at investigating the buckling characteristics of single layer latticed domes with triangular network pattern under the partially concentrated equipment loading in the cases of both having a geometrical imperfection and not having.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.10-19
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• 2014

Corrugated steel plates are made by fabricating thin steel plates to have trapezoidal or sinusoidal corrugation, and the corrugated plates are able to maintain high out-of-plane rigidity even when they are used instead of thick flat plates. Also, corrugated steel plates have almost no axial rigidity due to the accordion effect. Thus, if they are applied to the webs of plate girders, designing can be easily conducted so that the webs bear only shear stresses. However, unlike flat plates, the shear buckling of corrugated steel plates has very complex characteristics where buckling occurs due to the interaction of local and global buckling, besides local buckling and global buckling. For the investigation of the cause and characteristics of this interactive buckling, studies on sinusoidal corrugated steel plates are fewer than studies on trapezoidal corrugated steel plates. Therefore, in this study, the shear buckling characteristics of sinusoidal corrugated steel plates and the occurrence pattern of interactive buckling were investigated. For the calculation of shear buckling strength, a finite element program was used, and the analysis results were compared with the exact solution. In addition, the characteristics of buckling stress change and the change of buckling mode shape depending on corrugation thickness and shape parameter were analyzed, and by comparing these results with the results of a theoretical equation, the timing of buckling mode change was analyzed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.4 s.70
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• pp.405-416
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• 2005

This study contains the static buckling tests and static buckling analyses for small size grids and full size grids. The buckling tests and finite element analyses were performed to evaluate the buckling characteristics of the spacer grids in a pressurized water reactor fuel assembly and to evaluate the possibility of the prediction lot the buckling strength of spacer grids. The buckling tests were performed for small size grids and full size grids, and the correlations between buckling strength and the number of straps and the correlations between buckling strength and the number of rows are derived based on the test results. The static buckling analyses were performed to identify the effect of the number of rows and the number of columns on the buckling strength of spacer grid by a finite element method using ANSYS program and the results were compared with the buckling test results.

• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.463-472
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• 1998

The purpose of this paper is to analyze the buckling characteristics of rigidly-jointed single-layer latticed domes with square network by using the experimental and the theoretical techniques in order to develop a reasonable method of theoretical analysis for these domes. Two methods of theoretical analysis are applied; one is based on the Yamada's method of shell analogy and the other is based on the frame analysis method using the finite element method. The effects of the nonuniformity of rigidity-distribution in the circumferential direction and the rigidity of the covering material on both the prebuckling and the buckling characteristics are examined. The results indicate that these effects should be considered reasonably in the theoretical analyses.

• Computational Structural Engineering
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• v.9 no.3
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• pp.209-216
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• 1996

The primary objective of this paper is to grasp many characteristics of buckling behavior of latticed spherical domes under various conditions. The Arc-Length Method proposed by E.Riks is used for the computation and evaluation of geometrically nonlinear fundamental equilibrium paths and bifurcation points. And the direction of the path after the bifurcation point is decided by means of Hosono's concept. Three different nonlinear stiffness matrices of the Slope-Deflection Method are derived for the system with rigid nodes and results of the numerical analysis are examined in regard to geometrical parameters such as slenderness ratio, half-open angle, boundary conditions, and various loading types. But in case of analytical model 2 (rigid node), the post-buckling path could not be surveyed because of Newton-Raphson iteration process being diversed on the critical point since many eigenvalues become zero simultaneously.

• Journal of the KSME
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• v.33 no.7
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• pp.614-627
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• 1993

좌굴하기 쉬운 구조물을 설계할 때는 반드시 좌굴특성에 대한 어떤 직관을 가져야 한다. 이글의 목적은 셸 구조물이 비선형붕괴(nonlinear collapse), 분기좌굴(bifurcation buckling) 또는 이들 모드의 조합에 의해서 어떻게 좌굴될 것인가에 대한 감각을 전하는데 있다. 이 불안정에 대한 직관적 이해는 보강되고 여러 요소들로 조립되며 분지셸(branched shell)을 갖거나 복잡한 벽구 조를 갖는 실제 셸 구조물 등의 많은 예에 의해서 얻어질 수 있다. 이 글에서는 수식의 개발이 아니라 불안정의 예측에 주안점을 두고 있으며, 큰 처짐과 소성의 조합에 의해 발생되는 비선 형좌굴과 결함민감도가 특히 강조된다. 또한 최적화된 구조물의 국부 및 전체 불안정, 좌굴모드의 상호작용, 그리고 결함민감도(imperfection sensitivity) 등이 예시된다.