• Title/Summary/Keyword: Shell buckling

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Flexural Strength of HSB Plate Girder with Compact or Noncompact Web Due to Inelastic Lateral-Torsional Buckling (조밀 또는 비조밀 복부판을 갖는 HSB 플레이트거더의 비탄성 횡비틀림좌굴에 의한 휨강도)

  • Shin, Dong Ku;Cho, Eun Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.6A
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    • pp.399-409
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    • 2012
  • The flexural behavior of HSB plate girder with a non-slender web, due to inelastic lateral-torsional buckling, under uniform bending was investigated by the nonlinear finite element analysis. Both homogeneous sections fabricated from SM570-TMC, HSB600 or HSB800 steel and hybrid sections with HSB800 flanges and SM570-TMC web were considered. The flanges and web of selected noncomposite I-girders were modeled as thin shell elements and the geometrical and material nonlinear finite element analysis was performed by the ABAQUS program. The steel was assumed as an elasto-plastic strain hardening material. Initial imperfections and residual stresses were taken into account and their effects on the inelastic lateral-torsional buckling behavior were analyzed. The flexural strengths of selected sections obtained by the finite element analysis were compared with the nominal flexural strengths from KHBDC LSD, AASHTO LRFD, and Eurocode and the applicability of these codes in predicting the inelastic lateral torsional buckling strength of HSB plate girders with a non-slender web was assessed.

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.

Bending, Free Vibration and Buckling Analysis of Anisotropic Composite Laminated Plate and Shell Structures (비등방성 복합적층판 및 쉘 구조의 휨, 자유진동 및 좌굴해석)

  • Yoon, Seok Ho
    • Journal of Korean Society of Steel Construction
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    • v.11 no.1 s.38
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    • pp.55-67
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    • 1999
  • The ratios of elastic to shear modulus of the structures as laminated composite plates and shells, are very large. They are much susceptible to effect of shear deformation. In order to obtain the accurate solutions of laminated composite plate and shells, the effects of shear strain should be considered for the analysis and design of them. Especially, the more exact solution can be obtained in applying to higher-order shear deformation theory. Therefore, in this paper, the third-order shear deformation theory is used to present the distributions of bending, the characteristics of natural frequencies and the buckling load according to the effects of ply orientation, number of layers for the laminated composite plates and shells with simply supported boundary conditions.

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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.

Elastic Buckling Reliability Analysis of Circular Cylindrical Shell with Random Geometric Initial Imperfection (기하학적 초기결함을 갖는 원통형 쉘의 탄성 좌굴신뢰성 해석)

  • Y.S. Yang;D.K. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.2
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    • pp.103-114
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    • 1992
  • A study result of buckling reliability is presented for the axially compressed imperfect elastic cylinder. Multi-mode analysis program is developed from Karman-Donnell Equation for the calculation of the buckling load of the cylindrical she1l. Geometric intial imperfection is approximated by double Fourier series of which coefficients are assumed random variables with jointly normal distribution characteristics. Crude Monte Carlo simulation technique is used to calculate the probabilistic failure properties of several cases with various imperfection Conditions.

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An Experimental Study on the Buckling & Behaviour of Single-Layer Latticed Dome (단층 래티스 돔의 좌굴 및 거동에 관한 실험적 연구)

  • Kim, Cheol-Hwan;Jung, Hwan-Mok
    • Journal of Korean Association for Spatial Structures
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    • v.6 no.4 s.22
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    • pp.35-44
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    • 2006
  • The form-resistant Systems like a dome and shell are used more widely than post-beam structure system in large space structure. Single layer latticed dome system, one of the form-resistant system, has great merits in manufacturing and constructing but the failure mechanism is not clarified yet. The purpose of this paper is to find out the buckling characteristics of single-layer latticed domes with square network by using the experimental method. Major test parameters are the stiffness of lattice member and space of square lattice. The specimens are applied uniform loading of snow type.

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Buckling analysis of structures under combined loading with acceleration forces

  • Wang, Wenjing;Gu, Randy
    • Structural Engineering and Mechanics
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    • v.52 no.5
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    • pp.1051-1067
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    • 2014
  • The structures of concern in this study are subject to two types of forces: dead loads from the acceleration imposed on the structures as well as the installed operation machines and the additional adjustable forces. We wish to determine the critical values of the adjustable forces when buckling of the structures occurs. The mathematical statement of such a problem gives rise to a constrained eigenvalue problem (CEVP) in which the dominant eigenvalue is subject to an equality constraint. A numerical algorithm for solving the CEVP is proposed in which an iterative method is employed to identify an interval embracing the target eigenvalue. The algorithm is applied to four engineering application examples finding the critical loads of a fixed-free beam subject to its own body force, two plane structures and one wide-flange beam using shell elements when acceleration force is present. The accuracy is demonstrated using the first example whose classical solution exists. The significance of the equality constraint in the EVP is shown by comparing the solutions without the constraint on the eigenvalue. Effectiveness and accuracy of the numerical algorithm are presented.

Mechanical analysis of functionally graded spherical panel resting on elastic foundation under external pressure

  • Cao, Yan;Qian, Xueming;Fan, Qingming;Ebrahimi, Farbod
    • Structural Engineering and Mechanics
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    • v.74 no.2
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    • pp.297-311
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    • 2020
  • The main purpose of this study is to analyze the effects of external pressure on the vibration and buckling of functionally graded (FG) spherical panels resting of elastic medium. The material characteristics of the FG sphere continuously vary through the thickness direction based on the power-law rule. In accordance with first-order shear deformation shell theory and by the use of Ritz formulation the governing equations are presented. In this regard, the beam functions are applied in two-dimensions for different sets of boundary supports. The Winkler and Pasternak models of elastic foundations are also taken into account. In order to show the validity and applicability of the presented formulation, various comparison studies are given. Furthermore, a diverse range of numerical results is reported to check the impacts of geometrical and material parameters along with external pressure on the vibration and buckling analysis of FG spherical panels.

Numerical studies of the failure modes of ring-stiffened cylinders under hydrostatic pressure

  • Muttaqie, Teguh;Thang, Do Quang;Prabowo, Aditya Rio;Cho, Sang-Rai;Sohn, Jung Min
    • Structural Engineering and Mechanics
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    • v.70 no.4
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    • pp.431-443
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    • 2019
  • The present paper illustrates a numerical investigation on the failure behaviour of ring-stiffened cylinder subjected to external hydrostatic pressure. The published test data of steel welded ring-stiffened cylinder are surveyed and collected. Eight test models are chosen for the verification of the modelling and FE analyses procedures. The imperfection as the consequences of the fabrication processes, such as initial geometric deformation and residual stresses due to welding and cold forming, which reduced the ultimate strength, are simulated. The results show that the collapse pressure and failure mode predicted by the nonlinear FE analyses agree acceptably with the experimental results. In addition, the failure mode parameter obtained from the characteristic pressure such as interframe buckling pressure known as local buckling pressure, overall buckling pressure, and yield pressure are also examined through the collected data and shows a good correlation. A parametric study is then conducted to confirm the failure progression as the basic parameters such as the shell radius, thickness, overall length of the compartment, and stiffener spacing are varied.

Direct strength evaluation of the structural strength of a 500 cbm LNG bunkering ship

  • Muttaqie, Teguh;Jung, DongHo;Cho, Sang-Rai;Sohn, Jung Min
    • Structural Engineering and Mechanics
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    • v.81 no.6
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    • pp.781-790
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    • 2022
  • The present paper describes a general procedure of the structural safety assessment for the independent type C tank of LNG bunkering ship. This strength assessment procedure consists of two main scheme, global Finite Element Analysis (FEA) model primarily for hull structure assessment and detailed LNG Tank structures FEA model including the cylindrical tank itself and saddle-support structures. Two kinds of mechanism are used, fixed and slides constraints in fore and rear of the saddle-support structures that result in a variation of the reaction forces. Finite Element (FE) analyses have been performed and verified by the strength acceptance criteria to evaluate the safety adequacy of yielding and buckling of the hull and supporting structures. The detail of FE model for an LNG type C tank and its saddle supports was made, which includes the structural members such as cylindrical tank shell, ring stiffeners, swash bulkhead, and saddle supports. Subsequently, the FE buckling analysis of the Type C tank has been performed under external pressure following International Gas Containment (IGC) code requirements. Meanwhile, the assessment is also performed for yielding and buckling strength evaluation of the cylindrical LNG tank according to the PD 5500 unfired fusion welded pressure vessels code. Finally, a complete procedure for assessing the structural strength of 500 CBM LNG cargo tank, saddle support and hull structures have been provided.