• Title/Summary/Keyword: 좌굴

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A Study on the Elasto-Plasticity Behaviour According to the Yield Strength of a Ship's Plate (항복강도에 따른 선체판의 탄소성거동에 관한 연구)

  • 고재용;박주신
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • pp.27-31
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    • 2003
  • Recently, buckling is easy to happen as that High tensile steel that is the thin plate absence is used comprehensively for the structure. Specially, buckling is getting into important design standard in hull construction which use High tensile steel. Therefore, that grasp conduct exactly after buckling is important in stability of hull structure. In this study, examined closely about conduct and secondary buckling after initial buckling of thin plate structure which receive compressive load according to various kinds yield strength under simply supported condition that make by buckling strength formula standard in each payment in advance rule to place that is representative construction of hull in this research. Analysis method is F.E.M by ANSYS and complicated nonlinear behaviour to analyze such as secondary buckling in used arc-length method.

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Design and Buckling Analysis of Earth Retaining Struts Supported by High Strength Steel Pipe and PHC Pile (고강도 강관과 PHC파일이 활용된 흙막이 버팀보의 좌굴해석 및 설계)

  • Lim, Seung Hyun;Kim, In Gyu;Kim, Sung Bo
    • Journal of Korean Society of Steel Construction
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    • v.27 no.4
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    • pp.411-422
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    • 2015
  • The design and buckling behavior of earth retaining system supported by high strength steel pipe and PHC pile under compression is presented in this study. Buckling analysis of various strut system was investigated according to the strut total length(30m, 60m, 90m), three types of built-up columns and connection condition. Buckling loads calculated by F.E analysis was compared with the theoretical solution corresponding to diagonal buckling mode, local and global buckling mode of main strut. The design of the built-up column struts are performed based on design guide for high strength steel pipes and P-M diagram for built-up column with two PHC pile section.

Effects of Vehicle Loads on Thermal Buckling Behavior of Continuous Welded Rail Tracks (장대레일 궤도의 온도좌굴 거동에 미치는 열차하중의 영향)

  • Choi, Dong Ho;Kim, Ho Bae
    • Journal of Korean Society of Steel Construction
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    • v.12 no.6
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    • pp.727-736
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    • 2000
  • The present study investigates the influences of vehicle induced loads on the thermal buckling behavior of straight and curved continuous welded rail (CWR) tracks. Quasi-static loads model is assumed to determine the uplift region, which occurs due to the vertical track deflection induced by wheel loads of vehicle. The lateral loads of vehicle induced by weight, the speed, the superelevation and curvature of track, and other dynamic vehicle track interaction, are included in the ratio of lateral to vertical vehicle load. Parametric numerical analyses are perfomed to calculate the upper and lower critical buckling temperatures of CWR tracks, and the comparison between the results of this work and the previous results without vehicle is also included.

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Buckling Behaviors of Tapered Piles (테이퍼 말뚝의 좌굴 거동)

  • Lee, Joon-Kyu;Kwon, O-Il;Jeong, Tae-Seok;Park, Su-Han
    • Journal of the Korean Geotechnical Society
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    • v.35 no.2
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    • pp.19-27
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    • 2019
  • In this study, an analytical model is proposed to estimate the buckling responses of tapered piles. The governing differential equation of the soil-pile system considering the tapering and side friction of the pile and the soil nonhomogeneity is derived, which is numerically integrated by the Runge-Kutta method and then the eigenvalue of bucking load is determined by Regula-Falsi algorithm. For a cylindrical pile, the results obtained from this study are found to compare well with those reported in literature. Illustrative examples for buckling load and stress as well as buckled shape are provided to investigate the effects of dimensionless parameters related to the soil-pile system.

Application of a Fictitious Axial Force Factor to Determine Elastic and Inelastic Effective Lengths for Column Members of Steel Frames (강프레임 기둥 부재의 탄성 및 비탄성 유효좌굴길이 산정을 위한 가상축력계수의 적용)

  • Choi, Dong Ho;Yoo, Hoon;Lee, Yoon Seok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.2A
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    • pp.81-92
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    • 2010
  • In design of steel frames, it is generally believed that elastic system buckling analysis cannot predict real behaviors of structures, while inelastic system buckling analysis can give informative buckling behaviors of individual members considering inelastic material behavior. However, the use of Euler buckling equation with these system buckling analyses have the inherent problem that the methods evaluate unexpectedly large effective lengths of members having relatively small axial forces. This paper proposes a new method of obtaining elastic and inelastic effective lengths of all members in steel frames. Considering a fictitious axial force factor for each story of frames, the proposed method determines the effective lengths using the inelastic stiffness reduction factor and the iterative eigenvalue analysis. In order to verify the validity of the proposed method, the effective lengths of example frames by the proposed method were compared to those of previously established methods. As a result, the proposed method gives reasonable effective lengths of all members in steel frames. The effect of inelastic material behavior on the effective lengths of members was also discussed.

Study on Buckling Instability of Expansion Tube using Finite Element Method (유한요소법을 이용한 팽창튜브의 좌굴불안전성에 관한 연구)

  • Choi, Won-Mok;Kwon, Tae-Su;Jung, Hyun-Sung
    • Journal of the Korean Society for Railway
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    • v.13 no.2
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    • pp.147-151
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    • 2010
  • Since the kinetic energy is dissipated through plastic deformation energy generated in expanding process of the tube by a die. In order to successfully absorb the kinetic energy there should be no buckling in the expansion tube during expanding process. The buckling instability of the expansion tubes is affected by the initial boundary conditions, tube thickness and length. In this study, the effects of the tube thickness except length and initial boundary condition on the buckling instability are studied using a finite element method. In addition, Analysis procedure for nonlinear post-buckling analysis of expansion tube is established. There are three kinds of finite element analysis procedures for buckling analysis of expansion tube, quasi-static analysis, linear buckling analysis and nonlinear post-buckling analysis. The effect of the geometry imperfections defined as linear superimposition of buckling modes is considered in the nonlinear post-buckling analysis. The results of finite element analysis indicate that the buckling load increase with increase of thickness of tube and geometry imperfection. Finial buckling shapes are changed with respect to the geometry imperfection.

Improved Stability Design of Plane Frame Members (평면프레임 구조의 개선된 좌굴설계)

  • Kim, Moon Young;Song, Ju Young;Kyung, Yong Soo
    • Journal of Korean Society of Steel Construction
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    • v.18 no.2
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    • pp.225-237
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    • 2006
  • Based on the study conducted by Kim et al. (205a, b), an improved stability design method for evaluating the effective buckling lengths of beam-column members is proposed herein, using system elastic/inelastic buckling analysis and second-order elastic analysis. For this purpose, the stress-strain relationship of a column is inversely formulated from the reference load-carrying capacity proposed in design codes, so as to derive the tangent modulus of a column as a function of the slenderness ratio. The tangent stiffness matrix of a beam-column element is formulated using the so-called "stability functions," and elastic/inelastic buckling analysis Effective buckling lengths are then evaluated by extending the basic concept of a single simply-supported column to the individual members as one component of a whole frame structure. Through numerical examples of several structural systems and loading conditions, the possibilities of enhancement in stability design for frame structures are addressed by comparing their numerical results obtained when the present design method is used with those obtained when conventional stability design methods are used.

An Improved Stability Design of Plane Frames using System Buckling and Second-order Elastic Analysis (탄성좌굴 고유치 및 2차 탄성해석법을 이용한 평면강절프레임의 개선된 좌굴설계법)

  • Song, Ju-Young;Kyung, Yong-Soo;Kim, Nam-Il;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.2
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    • pp.159-168
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    • 2005
  • An improved stability design method for beam-columns of plane frames is proposed based on system buckling analysis and second-order elastic analysis. For this, the tangent stiffness matrix of beam-column elements is first derived using stability functions and a procedure for evaluating effective buckling lengths is reviewed using elastic system buckling analysis. And then the second-order analysis procedure is presented considering $P-\Delta$ effects and is compared with the closed-form solution through numerical examples. Design examples showing the validity of the proposed method we presented and their numerical results are compared with those obtained from the conventional stability design methods. Finally some useful conclusions are drawn.

In-plane elastic buckling strength of parabolic arch ribs subjected symmetrical loading (대칭 하중을 받는 포물선 아치 리브의 탄성 면내 좌굴 강도)

  • Moon, Ji Ho;Yoon, Ki Yong;Kim, Sung Hoon;Lee, Hak Eun
    • Journal of Korean Society of Steel Construction
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    • v.17 no.2
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    • pp.161-171
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    • 2005
  • When the in-plane flexural rigidity is small in relation to the applied load, the arch ribs may buckle to the in-plane direction. Designers should therefore determine the in-plane buckling strength. To determine the buckling strength of arch ribs, designers have to consider the material nonlinear response. But in the case of arch ribs having large slenderness ratio, arch ribs may buckle in the elastic range, and when the arch ribs have low slenderness ratio, elastic buckling strength is useful in the preliminary design. In this paper, elastic buckling strength of arch ribs, which are frequently used in practical design, is studied using nonlinear finite element method. In general, the relation between flexural rigidity and elastic buckling strength is linear. As seen from the results, however, when the arch ribs have low slenderness ratio, the relation between flexural rigidity and elastic buckling strength is nonlinear.

Buckling Strength of Cylindrical Shell Subjected to Axial Loads (축하중을 받는 원통형 쉘의 좌굴강도)

  • Kim, Seung Eock;Choi, Dong Ho;Lee, Dong Won;Kim, Chang Sung
    • Journal of Korean Society of Steel Construction
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    • v.13 no.2
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    • pp.191-200
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    • 2001
  • This paper presents buckling analysis of the cylindrical shell subjected to axial loads using numerical method. The modeling method, appropriate element type, and number of element are recommended by comparing with analytical solution. Based on the parametric study, buckling stress decreases significantly as the diameter-thickness ratio increases. These results are different from those obtained from buckling analysis of columns. The number of buckling half-wave in circumferential direction decreases as the diameter-height ratio increases. Buckling stress increases 1~2% as the thickness of base plate increases. Therefore the effect of base plate on buckling strength for cylindrical shell can be disregarded. Buckling stress significantly decreases as the amplitude of initial geometric imperfection used for calculating buckling stress is developed and it shows a good agreement with numerical results.

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