• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2001년도 추계학술대회 논문집
• /
• pp.475-480
• /
• 2001

In this study, a empirical equation which can be feasibly used to evaluate minimal track buckling strength without exact numerical analysis is presented. Parameter studies we carried out to investigate the effects of the individual factor on buckling strength. In order to simulate track buckling in the field as precisely as possible, a rigorous buckling model which accounts for all the important parameters is adopted. A empirical equation for prediction of minimal track buckling strength is derived by taking nonlinear regression of data which are obtained from numerical analyses. Its characteristics and applicability are investigated by comparing the results by the presented equation with the one by the equation which was presented in japan, and is frequently using in korea when designing track structure.

• Steel and Composite Structures
• /
• 제25권6호
• /
• pp.671-684
• /
• 2017

Elastic-plastic shear buckling behaviors of the web-post in a Castellated Steel Beam (CSB) with hexagonal web openings under vertical shear force were investigated further using Finite Element Model (FEM) based on a sub-model, which took the upper part of the web-post under horizontal shear force to represent the whole web-post under vertical shear force. A simplified design method for the web-post elastic-plastic shear buckling strength was proposed based on simulation results of the sub-model. Proper boundary conditions were applied to the sub-model to assure that its behaviors were identical to those of the whole web-post. The equation to calculate the thin plate elastic shear buckling strength was adopted as the basic form to build the design equation for elastic-plastic buckling strength of the sub-model. Parameters that might affect the elastic-plastic shear buckling strength of the whole web-post were studied. After obtaining the vertical shear buckling strength of a sub-model through FEM, the shear buckling coefficient k can be obtained through the back analysis. A practical calculation method for k was proposed through curving fitting the parameter study results. The elastic-plastic shear buckling strength of the web-post calculated using the proposed shear buckling coefficient k agreed well with that obtained from the FEM and test results. And it was more precise than those obtained from EC3 based on the strut model.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2007년도 정기 학술대회 논문집
• /
• pp.845-850
• /
• 2007

The empirical AISC panel zone thickness provision$(t_z\geq(d_z+w_z)$/90) to prevent the cyclic shear buckling of the panel zone was proposed based on the test data of Krawinkler et al. (1971) and Bertero et al. (1973) However, no published records of the equation development or any other background information appear to be available. The calibrated finite element analysis results of this study indicated that the AISC provision was not reasonable. In this study, through including the effects of the column axial force and the aspect ratio of the panel zone, a new equation for the relative strength between the beam and the panel zone was proposed such that the proposed equation can prevent the panel zone shear buckling and reduce the potential fracture associated with the kinking of the column flanges.

• 한국지반환경공학회 논문집
• /
• 제7권6호
• /
• pp.75-88
• /
• 2006

본 논문은 지중강판 구조물에 고강도강의 사용 가능성을 평가하였다. AASHTO(2004)와 CHBDC(2000)의 좌굴강도식의 차이점과 제정적인 배경, 주요 설계인자에 대한 매개변수를 연구하였다. 원형 지중강판구조물의 좌굴강도식은 지간, 토피고, 단면조건, 인장강도, 뒷채움 흙의 다양한 설계변수를 고려한 탄소성해석, 기하학적 비선형해석의 수치해석 결과를 토대로 제안하였다. 해석결과 CHBDC의 설계기준이 좌굴강도를 산정하는데 있어 적합하였으며, 고강도강 사용시 좌굴안정성도 확보되고 좌굴강도의 개선효과에 뛰어났다.

• Structural Engineering and Mechanics
• /
• 제43권4호
• /
• pp.449-458
• /
• 2012

Finite element buckling analysis of insulated transition flue ducts is carried out to determine the critical buckling load multipliers when subjected to axial compression for design process. Through this investigation, the results of numerical computations to examine the buckling strength for different possible duct shapes (cylinder, and circular-to-square) are presented. The load multipliers are determined through detailed buckling analysis taking into account the effects of geometrical construction and duct plate thickness which have great influence on the buckling load. Enhancement in the buckling capacity of such ducts by the addition of horizontal and vertical stiffeners is also investigated. Several models with varying dimensions and plate thicknesses are examined to obtain the linear buckling capacities against duct dimensions. The percentage improvement in the buckling capacity due to the addition of vertical stiffeners and horizontal Stiffeners is shown to be as high as three times for some cases. The study suggests that the best location of the horizontal stiffener is at 0.25 of duct depth from the bottom to achieve the maximum buckling capacity. A design equation estimating the buckling strength of geometrically perfect cylindrical-to-square shell is developed by using regression analysis accurately with approximately 4% errors.

• Steel and Composite Structures
• /
• 제43권3호
• /
• pp.341-351
• /
• 2022

This paper presents an inelastic buckling behavior analysis of rectangular hollow steel tubes with geometrical imperfections under elevated temperatures. The main variables are the temperature loads, slenderness ratios, and exposure conditions at high temperatures. The material and structural properties of steels at different temperatures are based on Eurocode (EN 1993-1-2, 2005). In the elastic buckling analysis, the buckling strength decreases linearly with the exposure conditions, whereas the inelastic buckling analysis shows that the buckling strength decreases in clusters based on the exposure conditions of strong and weak axes. The buckling shape of the rectangular steel column in the elastic buckling mode, which depicts geometrical imperfection, shows a shift in the position at which bending buckling occurs when the lower section of the member is exposed to high temperatures. Furthermore, lateral torsional buckling occurs owing to cross-section deformation when the strong axial plane of the model is exposed to high temperatures. The elastic buckling analysis indicates a conservative value when the model is exposed to a relatively low temperature, whereas the inelastic buckling analysis indicates a conservative value at a certain temperature or higher. The comparative results between the inelastic buckling analysis and Eurocode 3 show that a range exists in which the buckling strength in the design equation result is overestimated at elevated temperatures, and the shapes of the buckling curves are different.

• 한국공간구조학회논문집
• /
• 제7권3호
• /
• pp.79-86
• /
• 2007

최근, 건설되어지는 강구조물들의 장경간화 및 고층화로 인하여 고강도강재의 적용이 점차 요구되고 있다. 고강도강재는 적용구조물들을 공간 및 두께들 감소시킴으로써 외관성 및 경제성을 증가시킬 수 있는 장점이 있다. 이러한 고강도 강재의 적용을 위해서는 좌굴에 대한 기준이 필요하나 현재 국내의 경우 이러한 좌굴에 관한 연구가 미흡하다. 이에 본 연구에서는 3차원 탄소성 유한변위 프로그램을 이용하여 고강도 박스단면 트러스 부재의 좌굴거동에 대한 해석적 연구를 수행하였다. 고강도강재를 적용한 박스단면 트러스부재의 허용 압축응력에 대한 기준을 제안하였으며 그 적용성을 확인하였다. 그리고 고강도 트러스 부재의 설계에도 적용할 수 있음을 명확히 하였다.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
• /
• pp.147-151
• /
• 2003

In this study, we discussed the local buckling behavior of pultruded structural flexural members. Previous works were briefly reviewed and the local buckling behavior of orthotropic box-shape flexural members was discussed. The simplified form of equation for finding the width ratio of plate element of box-shape flexural members in which all plate components buckle simultaneously was proposed and the macro flow-chart for finding local buckling strength of pultruded flexural members was also suggested. To establish the design guide line for the local buckling of pultruded flexural members, further studies need to be performed as follows; the simplified form of solutions for finding the minimum buckling coefficient of orthotropic plate with various loading and boundary conditions including rotationally restrained boundary conditions, the simplified form of equation for calculating the coefficient of restraint provided by the adjacent plate elements.

• 한국강구조학회 논문집
• /
• 제23권6호
• /
• pp.679-690
• /
• 2011

판의 탄성좌굴에 관해서는 이미 많은 이론적 실험적 연구가 이루어져 여러 가지 경계조건 및 하중에 대해서 좌굴응력을 결정하는데 큰 어려움이 없다. 현재 플랜지 및 웨브판에 대한 설계기준도 휨에 대한 좌굴응력을 기준으로 하고 있으며, 후좌굴강도에 안전율을 적용하여 고려하도록 하고 있다. 그러므로 본 연구는 이상적인 조건하에서 전개되는 선형좌굴이론에서 뿐만이아니라, 유한처짐을 허용하는 극한강도 설계개념에 까지 확장되어진다. 또한, 이 개념에 근거한 실험적 연구가 이루어져 단순지지 조건을 만족시킬 수 있는 보강재에 대한 현 시방규정의 적정성을 분석 검토하고자 한다. 본 연구의 결과를 토대로 세장비의 변화에 따른 강상자형의 극한강도를 결정하는 식을 제시하고자 한다.

• Structural Engineering and Mechanics
• /
• 제65권2호
• /
• pp.141-154
• /
• 2018

In this study, the bend-buckling strength of the web in longitudinally stiffened plate girder was numerically investigated. The buckling strength of the reinforced web was evaluated through an eigenvalue analysis of the hypothetical model, in which the top and bottom junctions of the web to the flanges were assumed as simple support conditions. Major parameters in the analysis include asymmetrical cross-sectional property, aspect ratio of the web, stiffener locations, and bending rigidity of the stiffeners. The numerical results showed that current AASHTO LRFD specifications (2014) provides the buckling strength from considerably safe side to slightly unsafe side depending on the location of the stiffeners. A modified equation for buckling coefficients was proposed to solve the shortcomings. The bending rigidity requirements of longitudinal stiffeners stipulated in AASHTO were also investigated. It is desirable to increase the rigidity of the stiffeners when the aspect ratio is less than 1.0.