• Title, Summary, Keyword: 좌굴

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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.

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 Loads and Post-Buckling Behaviors of Shear Deformable Columns with Regular Cross-Section (전단변형을 고려한 정다각형 단면 기둥의 좌굴하중 및 후좌굴 거동)

  • Lee, Byeoung Koo;Lee, Tae Eun;Kwon, Yun Sil;Kim, Sun Gi
    • Journal of Korean Society of Steel Construction
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    • v.13 no.6
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    • pp.683-691
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    • 2001
  • Numerical methods are developed for solving the elastica and buckling load of tapered columns with shear deformation, subjected to a compressive end load. The linear, parabolic and sinusoidal tapers with the regular polygon cross-sections are considered, whose material volume and span length are always held constant. The differential equations governing the elastica of buckled column are derived. The Runge-Kutta method is used to integrate the differential equations, and the Regula-Falsi method is used to determine the rotation at left end and the buckling load, respectively. The numerical methods developed herein for computing the elastica and the buckling loads of the columns are found to be efficient and reliable.

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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.

A Study on the Geometric Parameters that Influence the Shear Buckling of Trapezoidally Corrugated Webs (제형파형강판의 전단거동에 영향을 미치는 기하학적 요소에 대한 연구)

  • Gill, Heung Bae;Lee, Seung Rok;Lee, Hak Eun;Lee, Pil Goo
    • Journal of Korean Society of Steel Construction
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    • v.15 no.5
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    • pp.591-601
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    • 2003
  • Because of their high out-of-plane and in-planes strength, trapezoidally corrugated plates have been increasingly used in buildings and bridges. If corrugated plates are used as the web of plate girders or prestressed concrete box girders, the flanges take most of the bending stress. On the other hand, the corrugated plate web supports shear stress due to the accordion effect. The corrugated plate web could fail by three different buckling modes: global, local, or interactive shear buckling. To determine the effects of geometric parameters on the buckling capacity of the corrugated plates, a parametric study was performed using finite dement method. The analysis results showed that the buckling capacity and modes depend on individual parameters as well as combinations of parameters.

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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A Study on the Design Criteria Relating to the Local Buckling of Pultruded FRP Structural Compression Members (펄트루젼 구조압축재의 국부좌굴 설계규준 개발에 관한 연구)

  • Joo, Hyung Joong;Lee, Seung Sik;Yoon, Soon Jong
    • Journal of Korean Society of Steel Construction
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    • v.18 no.5
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    • pp.597-606
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    • 2006
  • Since FRP materials have various advantages over steel, many research activities to use them for the civil engineering applications are now in progress. The present paper deals with the local buckling behavior of FRP pultruded members as a first step toward the development of design criteria. In the design of compression members, it is very important to know not only if local buckling occurs or not but also which plate component governs local buckling, but it is not easy to perform this work in a rigorous manner. In the present paper, a simple and accurate equation which can compute the coefficients of buckling of orthotropic plates and local buckling of pultruded compression members is suggested by performing rigorous analysis, energy analysis, and parametric study. The local buckling strength and the plate component governing the local buckling behavior of thin-walled pultruded compression members can be easily determined by using the proposed equation.

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.

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.

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.