• Title/Summary/Keyword: 비선형 후좌굴 해석

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Evaluation of Post-Buckling Residual Strength of H-Section Steel Column for Both Ends are Fixed Condition (양단고정 단부구속에 따른 H 형 강재기둥의 좌굴 후 잔존내력 평가)

  • Abebe, Daniel Yeshewawork;Choi, Jae Hyouk;Kim, Jin Hyang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.1
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    • pp.83-88
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    • 2013
  • Progressive collapse is a chain reaction of failures propagating throughout a portion of a structure that is disproportionate to the original local failure. When column members are subjected to unexpected load (compression load), they will buckle if the applied load is greater than the critical load that induces buckling. The post-buckling strength of the columns will decrease rapidly, but if there is enough residual strength, the members will absorb the potential energy generated by the impact load to prevent progressive collapse. Thus, it is necessary to identify the relationship of the load-deformation of a column member in the progressive collapse of a structure up to final collapse. In this study, we carried out nonlinear FEM analysis and based on deflection theory, we investigated the load-deformation relationship of H-section steel columns when both ends were fixed.

Postbuckling and Vibration Analysis of Cylindrical Composite Panel subject to Thermal Loads (열하중을 받는 복합적층 원통형 패널의 좌굴후 거동 및 진동해석)

  • Oh, Il-Kwon;Lee, In
    • Journal of the Korea Institute of Military Science and Technology
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    • v.2 no.2
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    • pp.148-156
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    • 1999
  • The thermal postbuckling and vibration characteristics of cylindrical composite panel subject to thermal loads are analyzed using finite elements. The von-Karman nonlinear displacement-strain relation based on the layerwise theory is applied to consider large deflections due to thermal loads. Cylindrical arc-length method is used to take into account the snapping phenomena. Thermal snapping and vibration characteristics are investigated for various structural parameters such as thickness ratio, shallowness angle and boundary conditions. The present results show that thermal snapping changes the mode shapes as well as static deformations.

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Analysis of Wrinkling for Creased Thin Membrane (접힌 자국이 있는 멤브레인의 주름 거동 해석)

  • Woo, Kyeong-Sik
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.9
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    • pp.851-858
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    • 2008
  • In this paper, the wrinkling behavior of vertically creased corner-loaded square membranes was studied using geometrically nonlinear post-buckling analysis. The membranes were modeled using shell elements, and the meshes were seeded with semi-random geometrical imperfection to instigate the buckling deformation. A pristine and creased membranes with various initial deployment angles were considered in the analyses and the results were compared. Results showed that local wrinkles initiated near the corner where the higher load was applied, which grew to form a single diagonal global wrinkle as the load ratio increased. It was also found that the local wrinkle initiation and the global wrinkle formation were significantly dependent on the initial deployment angles.

The Proposition of Efficient Nonlinear Solution Technique for Space Truss (공간 트러스에 대한 효율적인 비선형 해석 기법 제안)

  • 석창목;권영환
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.3
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    • pp.481-490
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    • 2002
  • The purpose of this paper is to evaluate the efficiency of various solution techniques and propose new efficient solution techniques for space trusses. Solution techniques used in this study are three load control methods (Newton-Raphson Method, modified Newton-Raphson Method, Secant-Newton Method), two load-displacement control methods(Arc-length Method, Work Increment Control Method) and three combined load-displacement control methods(Combined Arc-length Method I , Combined Arc-length MethodⅡ, Combined Work Increment Control Method). To evaluate the efficiency of these solution techniques, we must examine accuracy of their solutions, convergences and computing times of numerical examples. The combined load-displacement control methods are the most efficient in the geometric nonlinear solution techniques and in tracing post-buckling behavior of space truss. The combined work increment control method is the most efficient in tracing the buckling load of spate trusses with high degrees of freedom.

A Study on the Geometric Nonlinear Behaviour of Ship Plate by Energy Method (에너지법에 의한 선체판의 기하학적 비선형거동에 관한 연구)

  • Jae-Yong Ko
    • Journal of the Society of Naval Architects of Korea
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    • v.36 no.2
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    • pp.94-104
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    • 1999
  • Plate buckling is very important design criteria when the ship is composed of high tensile steel plates. In general, the plate element contributes to inplane stiffness against the action of inplane load. If the inplane stiffness of the plating decreases due to buckling including the secondary buckling, the flexural rigidity of the cross section of a ship's hull also decreases. In these cases, the precise estimation of plate's behaviour after buckling is necessary, and geometric nonlinear behaviour of isolated plates is required for structural system analysis. In this connection, the author investigated the geometric nonlinear behaviour of simply supported rectangular plates under uniaxial compression in the longitudinal direction in which the principle of minimum potential energy method is employed. Based on the energy method, elastic large deflection analysis of isolated palate is performed and simple expression are derived to discuss the bifurcation paint type buckling and limit point type buckling.

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Buckling of Filament Wound Thick Composite Cylinders under External Hydrostatic Pressure (외부 수압을 받는 필라멘트 와인딩 후판 복합재 원통의 좌굴 연구)

  • Moon, Chul-Jin;Hur, Seong-Hwa;Ahn, Jung-Hee;Kweon, Jin-Hwe;Choi, Jin-Ho;Cho, Jong-Rae;Cho, Sang-Rae
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.2
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    • pp.147-155
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    • 2009
  • The buckling and failure of filament wound thick composite cylinders under external hydrostatic pressure were investigated by the finite element analysis and test. ACOS, MSC.NASTRAN, and MSC.MARC were used for finite element analysis. T700 carbon-epoxy filament wound composite cylinders were fabricated to have winding angles of $[\pm30/90]_{FW}$, $[\pm45/90]_{FW}$, $[\pm60]_{FW}$, $[\pm60/90]_{FW}$, and tested to verify the finite element analysis. Among the softwares, ACOS predicted buckling load the best with about 1.7~14.3% deviation from test. Analysis and test shows cylinders do not recover the initial buckling pressure after buckling and directly lead to final failure.

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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    • 2005.05a
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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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Semi-rigid Elasto-Plastic Post Buckling Analysis of Space Frame by Using the Explicit Arc-Length Method (명시적 호장법을 이용한 공간프레임의 반강접 탄소성 후좌굴 해석)

  • Lee, Kyoung-Soo;Han, Sang-Eul
    • Journal of Korean Society of Steel Construction
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    • v.23 no.5
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    • pp.535-546
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    • 2011
  • In this paper, semi-rigid elasto-plastic post-buckling analysis of a space frame was performed using various explicit arc-length methods. Various explicit arc-length methodsand a large-deformation and small-strain elasto-plastic 3D space frame element with semi-rigid connections and plastic hinges were developed. This element can be appliedto both explicit and implicit numerical algorithms. In this study, the Dynamic Relaxation method was adopted in the predictor and corrector processesto formulate an explicit arc-length algorithm. The developed "explicit-predictor" or "explicit-corrector" were used in the elasto-plastic post-buckling analysis. The Eulerian equations for a beam-column with finite rotation, which considers the bowing effects, were adopted for the elastic system and extended to theinelastic system with a plastic hinge concept. The derived tangent stiffness matrix was asymmetrical due to the finite rotation. The joint connection elements were introduced for semi-rigidity using a static condensation technique. Semi-rigid elasto-plastic post-buckling analyses were carried out to demonstrate the potential of the developed explicit arc-length method and advanced space frame element in terms of accuracy and efficiency.

Stability and Post-Buckling Analyses of Thin-Walled Space Frames Using Finite Element Method (박벽 공간뼈대구조의 안정성 및 후좌굴 유한요소해석)

  • 김문영;안성원
    • Computational Structural Engineering
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    • v.10 no.4
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    • pp.205-216
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    • 1997
  • In order to trace the lateral post-buckling behaviors of thin-wafled space frames, a geometrically nonlinear finite element formulation is presented by applying incremental equilibrium equations based on the updated Lagrangian formulation and introducing Vlasov's assumption. The improved displacement field for symmetric thin-walled cross sections is introduced based on inclusion of second order terms of finite rotations, and the potential energy corresponding to the semitangential rotations and moments is consistently derived. For finite element analysis, tangent stiffness matrices of the thinwalled space frame element with 7 degrees of freedom including the restrained warping for each node are derived by using the Hermition polynomials as shape functions. A co-rotational formulation in order to evaluate the unbalanced loads is presented by separating the rigid body rotations and pure deformations from incremental displacements and evaluating the updated direction cosines of the frame element due to rigid body rotations and incremental member forces from pure deformations. Finite element solutions for the spatial buckling and post-buckling analysis of thin-walled space frames are presented and compared with available solutions and other researcher's results.

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Thickness Effect on Wrinkle-Crease Interaction for Thin Membrane (접힌자국이 있는 멤브레인에서 두께에 따른 주름거동의 변화)

  • Woo, Kyeong-Sik
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.5
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    • pp.421-426
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    • 2010
  • In this paper, the thickness effect on the wrinkle-crease interaction behavior of corner-loaded creased square membranes was studied using geometrically nonlinear post-buckling analysis. The membranes were modeled using shell elements, and the meshes were seeded with semi-random geometrical imperfection to instigate the buckling deformation. Results indicated that the wrinkle-crease interaction behavior was significantly dependent on the membrane thickness. Both the global and local wrinkles developed earlier as the thickness decreased. It was also found that the wrinkling behavior depended on the initial deployment angle in which the local wrinkle initiation occurred earlier, while the global wrinkle formation was delayed as the angle increased.