• Title, Summary, Keyword: 좌굴후 거동

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A Study on the Buckling and Postbuckling Behaviors of Laminated Composite Plates and Stiffened Laminated Composite Panels by Finite Element Method (유한요소법을 이용한 복합적층판과 보강된 복합적층 패널의 좌굴 및 좌굴후 거동에 관한 연구)

  • 허성필;양원호;성기득;조명래
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.12 no.4
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    • pp.599-606
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    • 1999
  • 복합 적층 판과 보강 재를 설치한 보강된 복합 적층 패널의 좌굴을 고려한 설계에서, 좌굴이 항상 구조물의 최종 파손을 의미하는 것은 아니므로 이들의 좌굴 및 좌굴 후 거동에 대한 정확한 이해와 연구가 필요하다. 본 연구에서는 유한요소 법을 이용하여 적층 메커니즘과 섬유 배향각, 적층 순서 등이 복합 적층 판과 보강된 복합 적층 패널의 좌굴 및 좌굴 후 거동에 미치는 영향을 체계적으로 해석하였고, 각 변수에 따른 좌굴 및 좌굴 후 거동 특성을 분석하였다.

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A study on the Thermal Buckling and Postbuckling of a Laminated Composite Beam with Embedded SMA Actuators (형상기억합금 선을 삽입한 복합적층 보의 열좌굴 및 좌굴후 거동에 관한 연구)

  • Choi, S.;Lee, J.J.;Lee, D.C.
    • Composites Research
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    • v.12 no.3
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    • pp.55-65
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    • 1999
  • In this paper, the thermal buckling and postbuckling behaviour of composite beam with embedded shape memory alloy (SMA) wires are investigated experimentally and analytically. The results of thermal buckling tests on uniformly heated, clamped, composite beam embedded with SMA wire actuators are presented and discussed in consideration of geometric imperfections, slenderness ratio of beam and embedding position of SMA wire actuators. The shape recovery force can reduce the thermal expansion of composite laminated beam, which result in increment of the critical buckling temperature and reduction of the lateral deflection of postbuckling behaviours. It is presented quantitatively on the temperature-load-deflection behaviour records how the shape recovery force affects the thermal buckling. The cross tangential method is suggested to calculate the critical buckling temperature on the temperature-deflection plot. Based on the experimental analysis, the new formula is also proposed to describe the critical buckling temperature of a laminated composite beam with embedded SMA wire actuators.

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Analytical Method for Elastoplastic Behavior of Truss element under Cyclic Axial Loading (반복 축 하중을 받는 트러스 요소의 탄소성 좌굴거동 해석기법에 관한 연구)

  • Baek, Ki Youl
    • Journal of Korean Society of Steel Construction
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    • v.20 no.3
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    • pp.377-387
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    • 2008
  • The post-buckling behavior of slender members, such as the chord of truss structures generally implies extreme strength degradation. The buckling strength is usually determined as the performance of the compressed steel members, so it is important to understand the exact buckling behavior of a member in order to design the entire structure. A target analytical model is usually divided by beam or shell element when we simulate the buckling behavior of a compressed steel member such as atruss member. In this case, it is possible to accurately obtain the behavior, but such would be expensive and would require experience inanalysis even in monotonic loading. In this paper, we propose a consistent and convenient method to analyze the post-buckling behavior of elastoplastic compression members. The present methods are formulated to satisfy the second law of thermodynamics. Three numerical examples were tested to determine the validity of the proposed model in cyclic loading with comparable F.E.M results.

A Study on the Secondary Buckling of Plate Structure by Arc Length Method (호장증분법에 의한 판구조물의 2차좌굴거동에 관한 연구)

  • 고재용;최익창
    • Computational Structural Engineering
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    • v.11 no.4
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    • pp.209-218
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    • 1998
  • 고장력강이 구조강재로서 널리 사용되고 있다. 구조물의 극심한 하중을 받게되면 최종강도에 도달할 때까지 좌굴을 동반하게 된다. 그러므로, 고장력강판의 좌굴에 대한 정확한 평가가 중요한 설계기준이 되고 있다. 그러나, 고장력강을 효율적으로 사용하기 위해서는 좌굴허용설계를 도입할 수 있도록 판구조물의 판두께가 얇아져야 한다. 따라서, 박판구조물의 합리적인 설계를 하기 위해서는 좌굴후거동해석이 매우 중요하다. 그러므로, 본 논문에서는 호장증분법을 이용하여 압출하중을 받는 박판구조물의 초기좌굴후거동과 2차좌굴강도에 대하여 규명하였다. 특히, 호장증분법을 좌굴정에서의 하중경로를 추정하기 위하여 적용하였다.

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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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Postbuckling Analysis of laminated composite-stringer stiffened-Curved panels Loaded in Local compression. (국부 압축력을 받는 스트링거 보강 복합적층 만곡 판넬의 좌굴후 거동해석)

  • 김조권
    • Composites Research
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    • v.13 no.1
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    • pp.25-32
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    • 2000
  • In this paper, postbuckling behavior of laminated composite-stringer stiffened-curved panels loaded in local compression is analyzed using the finite element program developed. Postbuckling Analysis is performed in dividing the panel behavior into three basic parts. The eight node degenerated shell element is used in modelling both panel and stiffeners, and the updated Lagrangian description method based on the 2nd Piola-Kirchhoff stress tensor and the Green strain tensor is used for the nonlinear finite element formulation. The progressive failure analysis is adopted in order to grasp the failure characteristics. The postbuckling experiment of the laminated composite-stiffened-curved panel had been done to verify the finite element analysis. The buckling load and the postbuckling ultimate load are compared in parametric study.

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Buckling and Postbuckling Control of a Composite Beam with Embedded SMA Wire Actuators (형상기억합금 선 작동기를 삽입한 복합적층 보의 좌굴 및 좌굴후 제어)

  • Choi, S.;Lee, J.J.;Seo, D.C.;Choi, S.W.
    • Composites Research
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    • v.12 no.3
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    • pp.45-54
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    • 1999
  • In this paper, an experimental study on the buckling and postbuckling control of a laminated composite beam with eccentrically embedded SMA wire actuators is performed. For the purpose of enhancing the critical buckling load, buckling control is investigated through the use of reactive moment associated with the shape recovery force of SMA wire actuators. To improve the control authority for the buckling and postbuckling control of the SMA-composite beam, closed-loop control is used. The buckling and postbuckling control behaviours are presented and discussed qualitatively and quantitatively on loaddeflection plots considering the stacking sequence of the laminate, slenderness ratio of the beam and activation conditions of the SMA wire actuators. By maintaining the desired deflection shape with the proper reactive moment, buckling control can be extended to the postbuckling of the SMA-composite beam subjected to an external load.

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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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Ultimate Strength varying the Yield Stress of a Ship's Plate (선체판의 항복응력 변화에 따른 최종강도거동에 관한 연구)

  • Ko Jae-Yong;Lee Jun-Kyo;Park Joo-Shin
    • Proceedings of KOSOMES biannual meeting
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    • pp.179-183
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    • 2005
  • The High-tensile steel has been recognized as a promising concept for structural design of light weight transportation systems such as aircraft high speed trains and fast ships. Using the high-tensile steel has been widely used in ship structures, and this enables to reduce the plate thickness. Using the high-tensile steel effectively for a ship hull, the plate thickness becomes thin so that plate buckling may take place. Therefore, precise assessment of the behavior of plate above primary buckling load is important. In this study, examined closely secondary buckling behavior after initial buckling of thin plate structure which operated compressive load according to the various kinds of yield stress with simply supported boundary condition. Analysis method is F.E.M by commercial program(ANSYS V7.1) and complicated nonlinear behaviour can analyze using art-length method about secondary buckling.

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Stability and Post-buckling Analysis of Stiffened Plate and Shell Structures (보강된 판 및 쉘구조의 좌굴 및 후좌굴해석)

  • 김문영;최명수;민병철
    • Computational Structural Engineering
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    • v.11 no.4
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    • pp.155-168
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    • 1998
  • 보강된 판 및 쉘구조의 안정성 및 후좌굴을 포함하는 기하학적 비선형 해석을 수행하기 위하여, total Lagrangian formulation에 근거한 연속체의 증분평형방정식으로부터 변형된 쉘요소인 유한요소이론을 제시하였다. 쉘구조의 곡률이 불연속적으로 변하거나 쉘부재들이 유한한 각도로 만나는 보강된 판 및 쉘구조의 비선형 해석이 가능하도록 주부재와 보강재 간의 연결점에 대한 일반적인 변환관계를 제시하였으며 좌굴해석 및 기하학적 비선형해석의 경우에 해의 정확성 및 수렴성을 개선시키기 위하여 접선강도행렬 산정시 회전각의 2차항을 포함시켰다. 또한, shear locking 현상을 극복하기 위하여 감차적분을 적용하였고 쉘구조의 좌굴해석에서는 power method를 적용하여 해석의 효율을 높였으며, 후좌굴해석에서는 변위 및 하중증분법을 적절히 결합시켜 보강된 쉘구조의 후좌굴 거동추적이 용이하였다. 또한, 입력자료를 손쉽게 준비하고 좌굴모드 및 후좌굴거동을 효율적으로 분석하기 위하여 전, 후 처리 프로그램을 개발하였고 다양한 해석예제를 통하여 다른 문헌의 해석결과를 비교함으로써 본 연구에서 개발된 유한요소 해석프로그램의 타당성 및 정확성을 입증하였다.

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