• Title, Summary, Keyword: buckling mode

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Buckling Characteristics of the KALIMER-150 Reactor Vessel Under Lateral Seismic Loads and the Experimental Verification Using Reduced Scale Cylindrical Shell Structures

  • Koo Gyeong-Hoi;Lee Jae-Han
    • Nuclear Engineering and Technology
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    • v.35 no.6
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    • pp.537-546
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    • 2003
  • The purpose of this paper is to investigate the buckling characteristics of a conceptually designed KALIMER-150(Korea Advanced LIquid MEtal Reactor, 150MWe) reactor vessel and verify the buckling behavior using the reduced scale cylindrical shell structures. To do this, nonlinear buckling analyses using finite element method and evaluation formulae are carried out. From the results, the KALIMER-150 reactor vessel exhibits a dominant bending buckling mode and is significantly affected by the plastic behavior. The interaction effects with the vertical seismic load cause the lateral buckling load to be slightly decrease. From the results of the buckling experiments using reduced scaled cylindrical shell structures, it is verified that the buckling modes such as pure bending, pure shear, and mixed(bending plus shear) mode clearly appear under a lateral load corresponding to the slenderness ratio of cylinder.

Influence of Couplings on the Buckling Behavior of Composite Laminates with a Delamination (층간분리로 인한 연계강성이 복합재 적층판의 좌굴거동에 미치는 영향)

  • 김효진;홍창선
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.2
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    • pp.354-362
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    • 1995
  • The finite element modeling is used to study the buckling and postbuckling behavior of composite laminates with an embedded delamination. Degenerated shell element and rigid beam element are utilized for the finite element modeling. In the nonlinear finite element formulation, the updated Lagrangian description method based on the second Piola-Kirchhoff stress tensor and the Green strain tensor is used. The buckling and postbuckling behavior of composite laminates with a delamination are investigated for various delamination sizes, stacking sequences, and boundary conditions. It is shown that the buckling load and postbuckling behavior of composite laminates depend on the buckling model which is determined by the delamination size, stacking sequence and boundary condition. Also, results show that introduction of couplings can reduce greatly the buckling load.

Secondary buckling analysis of spherical caps

  • Kato, Shiro;Chiba, Yoshinao;Mutoh, Itaru
    • Structural Engineering and Mechanics
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    • v.5 no.6
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    • pp.715-728
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    • 1997
  • The aim of this paper is to investigate the secondary buckling behaviour and mode-coupling of spherical caps under uniformly external pressure. The analysis makes use of a rotational finite shell element on the basis of strain-displacement relations according to Koiter's shell theory (Small Finite Deflections). The post-buckling behaviours after a bifurcation point are analyzed precisely by considering multi-mode coupling between several higher order harmonic wave numbers: and on the way of post-buckling path the positive definiteness of incremental stiffness matrix of uncoupled modes is examined step by step. The secondary buckling point that has zero eigen-value of incremental stiffness matrix and the corresponding secondary mode are obtained, moreover, the secondary post-buckling path is traced.

An Approximate Method for the Buckling Analysis of a Composite Lattice Rectangular Plate

  • Kim, Yongha;Kim, Pyunghwa;Kim, Hiyeop;Park, Jungsun
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.3
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    • pp.450-466
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    • 2017
  • This paper defines the modified effective membrane stiffness, bending stiffness considering the directionally dependent mechanical properties and mode shape function of a composite lattice rectangular plate, which is assumed to be a Kirchhoff-Love plate. It subsequently presents an approximate method of conducting a buckling analysis of the composite lattice rectangular plate with various boundary conditions under uniform compression using the Ritz method. This method considers the coupled buckling mode as well as the global and local buckling modes. The validity of the present method is verified by comparing the results of the finite element analysis. In addition, this paper performs a parametric analysis to investigate the effects of the design parameters on the critical load and buckling mode shape of the composite lattice rectangular plate based on the present method. The results allow a database to be obtained on the buckling characteristics of composite lattice rectangular plates. Consequently, it is concluded that the present method which facilitates the calculation of the critical load and buckling mode shape according to the design parameters as well as the parametric analysis are very useful not only because of their structural design but also because of the buckling analysis of composite lattice structures.

Buckling and dynamic characteristics of a laminated cylindrical panel under non-uniform thermal load

  • Bhagat, Vinod S.;Pitchaimani, Jeyaraj;Murigendrappa, S.M.
    • Steel and Composite Structures
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    • v.22 no.6
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    • pp.1359-1389
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    • 2016
  • Buckling and free vibration behavior of a laminated cylindrical panel exposed to non-uniform thermal load is addressed in the present study. The approach comprises of three portions, in the first portion, heat transfer analysis is carried out to compute the non-uniform temperature fields, whereas second portion consists of static analysis wherein stress fields due to thermal load is obtained, and the last portion consists of buckling and prestressed modal analyzes to capture the critical buckling temperature as well as first five natural frequencies and associated mode shapes. Finite element is used to perform the numerical investigation. The detailed parametric study is carried out to analyze the effect of nature of temperature variation across the panel, laminate sequence and structural boundary constraints on the buckling and free vibration behavior. The relation between the buckling temperature of the panel under uniform temperature field and non-uniform temperature field is established using magnification factor. Among four cases considered in this study for position of heat sources, highest magnification factor is observed at the forefront curved edge of the panel where heat source is placed. It is also observed that thermal buckling strength and buckling mode shapes are highly sensitive to nature of temperature field and the effect is significant for the above-mentioned temperature field. Furthermore, it is also observed that the panel with antisymmetric laminate has better buckling strength. Free vibration frequencies and the associated mode shapes are significantly influenced by the non-uniform temperature variations.

Buckling and vibration behavior of a non-uniformly heated isotropic cylindrical panel

  • Bhagata, Vinod S.;Pitchaimani, Jeyaraj;Murigendrappa, S.M.
    • Structural Engineering and Mechanics
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    • v.57 no.3
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    • pp.543-567
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    • 2016
  • This study attempts to address the buckling and free vibration characteristics of an isotropic cylindrical panel subjected to non-uniform temperature rise using numerical approach. Finite element analysis has been used in the present study. The approach involves three parts, in the first part non-uniform temperature field is obtained using heat transfer analysis, in the second part, the stress field is computed under the thermal load using static condition and, the last part, the buckling and pre-stressed modal analysis are carried out to compute critical buckling temperature as well as natural frequencies and associated mode shapes. In the present study, the effect of non-uniform temperature field, heat sink temperatures and in-plane boundary constraints are considered. The relation between buckling temperature under uniform and non-uniform temperature fields has been established. Results revealed that decrease (Case (ii)) type temperature variation field influences the fundamental buckling mode shape significantly. Further, it is observed that natural frequencies under free vibration state, decreases as temperature increases. However, the reduction is significantly higher for the lowest natural frequency. It is also found that, with an increase in temperature, nodal and anti-nodal positions of free vibration mode shapes is shifting towards the location where the intensity of the heat source is high and structural stiffness is low.

Evaluation and Test of Slenderness Ratio Effect on Buckling Characteristics of Thin Cylindrical Structures Subjecting the Shear Loads (전단하중을 받는 얇은 원통구조물의 세장비에 따른 좌굴특성 평가 및 시험)

  • 구경회;김종범;이재한
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.3
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    • pp.535-543
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    • 2002
  • The purpose of this paper is to investigate the slenderness ratio effect on buckling characteristics of thin cylindrical structures subjecting the shear loads in detail. To do this, the buckling strength evaluations were carried out with using the evaluation formulae proposed by J. Okada. From the results of the buckling strength evaluations, the three types of staled cylindrical test specimen, which have L/R=3.1, 1.6, and 1.0, are determined for the numerical analyses and tests. From results, target slenderness ratio over L/R=3 results in dominant bending buckling mode, smaller slenderness ratio under L/R=1 results in dominant shear buckling mode, and near L/R=1.6 region shows the mixed buckling mode which has the bending and shear buckling mode simultaneously. Most results of buckling characteristics obtained by the numerical analyses and the evaluation formulae we in good agreement with those of tests.

Experimental Study of Buckling Behavior of Composite Laminates with an Embedded Delamination (내재된 층간분리가 존재한 복합재 적층판의 좌굴거동에 대한 실혐 연구)

  • Kim, Hyo-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.8
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    • pp.2491-2500
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    • 1996
  • An experimental and analytical investigation is performed to study the buckling behavior of composite laminates with an embedded delamination. It is of particular interest to veryfy whether delamination growth cddurs with continuming deformation after buckling of composite laminates with an embedded delamination. Experiments are conducted for [0/sub 4///90/sub 8//0/sub 4/]/sub r/ laminates with delamination size in which local buckling mode governs buckling. Results show that delamination growth occurs in hgigher load after buckling and is accompanid by other damage mechanisms such as splitting. Also, it is found that transverse deformation before difurcation buckling is due to initial imperfection and structure such as plate with small bending stiffness is sensitive to that.

Analysis on the Elastic Shear Buckling Characteristics of Corrugated Steel Plate in Accordance with Corrugation Shape (형상에 따른 주름강판의 탄성전단좌굴 특성 및 경향성 분석 연구)

  • Shon, Su-Deok;Yoo, Mi-Na;Lee, Seung-Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.6
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    • pp.11-20
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    • 2014
  • This paper aims at comparing and analyzing shear buckling characteristics between sinusoidal corrugation shape and trapezoidal one. For this, I adopted the equal-length trapezoidal corrugation and sinusoidal one for the analytical models, and analyzed their shear buckling characteristics through linear buckling analysis and on its theory. Generally, the shear buckling shapes of corrugated steel plates are classified into local buckling, global buckling, and interactive buckling from the two buckling modes. Sinusoidal corrugation shape, unlike trapezoidal corrugation, does not have flat sides, which causes another tendency in shear buckling mode. Especially, the changes and different aspects of shear buckling on the boundary between local buckling and global buckling appear in different corrugation shapes. According to the analysis results, interactive buckling mode appeared on the boundary of local buckling and global bucking in trapezoidal corrugation. However, in the case of corrugated steel plates with sinusoidal configuration, interactive buckling mode appeared in the part where global bucking takes place. Besides, trapezoidal shapes are of advantages on shear buckling resistance in the local buckling section, and so are sinusoidal shapes in the global buckling section.

Effect of crack location on buckling analysis and SIF of cracked plates under tension

  • Memarzadeh, Parham;Mousavian, Sayedmohammad;Ghehi, Mohammad Hosseini;Zirakian, Tadeh
    • Steel and Composite Structures
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    • v.35 no.2
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    • pp.215-235
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    • 2020
  • Cracks and defects may occur anywhere in a plate under tension. Cracks can affect the buckling stability performance and even the failure mode of the plate. A search of the literature reveals that the reported research has mostly focused on the study of plates with central and small cracks. Considering the effectiveness of cracks on the buckling behavior of plates, this study intends to investigate the effects of some key parameters, i.e., crack size and location as well as the plate aspect ratio and support conditions, on the buckling behavior, stress intensity factor (SIF), and the failure mode (buckling or fracture) in cracked plates under tension. To this end, a sophisticated mathematical code was developed using MATLAB in the frame-work of extended finite element method (XFEM) in order to analyze the buckling stability and collapse of numerous plate models. The results and findings of this research endeavor show that, in addition to the plate aspect ratio and support conditions, careful consideration of the crack location and size can be quite effective in buckling behavior assessment and failure mode prediction as well as SIF evaluation of the cracked plates subjected to tensile loading.