• Title, Summary, Keyword: Postbuckling Behavior

Search Result 29, Processing Time 0.119 seconds

Postbuckling Behavior of Composite Laminated Cylinder under Lateral Pressure (횡방향 압력을 받는 복합적층 원통실린더의 좌굴후 거동해석)

  • 조종두;김헌주
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.843-846
    • /
    • 1994
  • The bucking and postbuckling behavior of composite laminated long cylinders under lateral pressure are investigated by the nonlinear finite element method. A long cylinder of 3-D shell problem is modelled as 2-D plane strain problem for analysis. And for the finite element analysis, eight nodes quadratic element is utilized. Arc-length method is adopted for the iteration and load-increment along postbuckling equilibrium path. The composite laminated cylinders in study are composed of cross-plied uniaxially reinforced shells. As a prsult, buckling load and postbuckling behavior are discussed.

  • PDF

Effect of out-of-plane defects on the postbuckling behavior of graphene sheets based on nonlocal elasticity theory

  • Soleimani, Ahmad;Dastani, Kia;Hadi, Amin;Naei, Mohamad Hasan
    • Steel and Composite Structures
    • /
    • v.30 no.6
    • /
    • pp.517-534
    • /
    • 2019
  • In this paper, the effects of inevitable out-of-plane defects on the postbuckling behavior of single-layered graphene sheets (SLGSs) under in-plane loadings are investigated based on nonlocal first order shear deformation theory (FSDT) and von-Karman nonlinear model. A generic imperfection function, which takes the form of the products of hyperbolic and trigonometric functions, is employed to model out-of-plane defects as initial geometrical imperfections of SLGSs. Nonlinear equilibrium equations are derived from the principle of virtual work and variational formulation. The postbuckling equilibrium paths of imperfect graphene sheets (GSs) are presented by solving the governing equations via isogeometric analysis (IGA) and Newton-Raphson iterative method. Finally, the sensitivity of the postbuckling behavior of GS to shape, amplitude, extension on the surface, and location of initial imperfection is studied. Results showed that the small scale and initial imperfection effects on the postbuckling behavior of defective SLGS are important and cannot be ignored.

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
    • /
    • v.19 no.2
    • /
    • pp.354-362
    • /
    • 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.

Postbuckling and Damage Analysis of Composite Laminated Hollow Cylinder under Lateral Pressure (횡방향 압력을 받는 복합적층 원통실린더의 좌굴후 거동 및 손상해석)

  • Chongdu Cho;Guiping Zhao;HeonJu Kin
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.17 no.4
    • /
    • pp.163-172
    • /
    • 2000
  • The postbuckling behavior and progressive damage of composite laminated cylindrical shell under uniform external pressure were investigated by nonlinear finite element method programming. For the finite element analysis, nine-node 3-D degenerated elements were utilized, and arc-length method including line search was adopted for the iteration and load-increment along postbuckling equilibrium path. As results. buckling load, postbucking behavior, and progressive failure f3r various composite laminated cylindrical shells were discussed.

  • PDF

Postbuckling analysis of laminated composite shells under shear loads

  • Jung, Woo-Young;Han, Sung-Cheon;Lee, Won-Hong;Park, Weon-Tae
    • Steel and Composite Structures
    • /
    • v.21 no.2
    • /
    • pp.373-394
    • /
    • 2016
  • The postbuckling behavior of laminated composite plates and shells, subjected to various shear loadings, is presented, using a modified 8-ANS method. The finite element, based on a modified first-order shear deformation theory, is further improved by the combined use of assumed natural strain method. We analyze the influence of the shell element with the various location and number of enhanced membrane and shear interpolation. Using the assumed natural strain method with proper interpolation functions, the present shell element generates neither membrane nor shear locking behavior even when full integration is used in the formulation. The effects of various types of lay-ups, materials and number of layers on initial buckling and postbuckling response of the laminated composite plates and shells for various shear loading have been discussed. In addition, the effect of direction of shear load on the postbuckling behavior is studied. Numerical results and comparisons of the present results with those found in the literature for typical benchmark problems involving symmetric cross-ply laminated composites are found to be excellent and show the validity of the developed finite element model. The study is relevant to the simulation of barrels, pipes, wing surfaces, aircrafts, rockets and missile structures subjected to intense complex loading.

Buckling Analysis of Axisymmetric Shells by Incremental Finite Element Mothod (증분형(增分形) 유한요소법(有限要素法)에 의한 축대칭(軸對稱) Shell구조(構造)의 좌굴해석(挫屈解析))

  • J.B.,Kim;C.Y.,Kim
    • Bulletin of the Society of Naval Architects of Korea
    • /
    • v.22 no.1
    • /
    • pp.21-30
    • /
    • 1985
  • This paper deals whth the buckling as well as postbuckling analysis of axisymmertric shells taking the initial deflection effects into account. Incremental equilibrium equations, based on the principle of virtual work, were derived by the finite element method, the successive step-by-step Newton-Raphson iterative technique was adopted. To define the transition pattern of postbuckling behavior from the prebuckling state more accurately, a simple solution method was developed, i.e. the critical load was calculated by the load extrapolation method with the determinant of tangent stiffness matrix and the equilibrium configuration in the immediate postbuckling stage was obtained by perturbation scheme and eigenvalue analysis. Degenerated isoparametric shell elements were used to analyse the axisymmetric shell of revolution. And by the method developed in this paper, the computer program applicable to the nonlinear analysis of both thin and moderately thick shells was constructed. To verify the capabilities and accuracies of the present solution method, the computed results were compared with the results of analytical solutions. These results coincided fairly well in both the small deflection and large deflection ranges. Various numerical analyses were done to show the effect of initial deflection and shape of shells on buckling load and postbuckling behavior. Futhermore, corrected directions of applied loads at every increment steps were used to determine the actual effects of large deflection in non-conservative load systems such as hydrostatic pressure load. The following conclusions can be obtained. (1) The method described in this paper was found to be both economic and effective in calculating buckling load and postbuckling behavior of shell structure. (2) Buckling and postbuckling behavior of spherical caps is critically dependent upon their geometric configuration, i.e. the shape of spherical cap and quantities of the initial deflection. (3) In the analysis of large deflection problems of shells by the incremental method, corrections of the applied load directions are needed at every incremental step to compensate the follower force effects.

  • PDF

Optimization for Buckling and Postbuckling Behavior of Stiffened Fiber Reinforced Composite Panels (보강된 섬유강화 복합재료 패널의 좌굴해석 및 파손강도의 최적 설계)

  • Lee, Gwang-Rog;Yang, Won-Ho;Cho, Mung-Rae;Sung, Ki-Deug
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.913-919
    • /
    • 2001
  • In this study, fiber orientation of stiffener was conducted to increase buckling load or failure load in each case with a different design value and a different objective function for stiffened laminated composite panel of I-type under compression loading. Regarding each of buckling load or failure load as objective function, optimum design was carried out. In respect of optimum design, it was investigated that optimum shape for buckling could improve fail load for postbuckling, because it was difficult to investigate the optimization of postbuckling which need long analysis times for nonlinear analysis.

  • PDF

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
    • /
    • v.13 no.1
    • /
    • pp.25-32
    • /
    • 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.

  • PDF

Buckling and Postbuckling Behavior of Stiffened Laminated Composite Panels (보강된 복합적층 판넬의 좌굴 및 좌굴후 거동 연구)

  • Lee, In-Cheol;Gyeong, U-Min;Gong, Cheol-Won;Hong, Chang-Seon;Kim, Cheon-Gon
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.20 no.10
    • /
    • pp.3199-3210
    • /
    • 1996
  • The buckling and postbuckling behaviors were sutdied analytically and experimentally for stiffened laminated composite panels under compression loading. The panels with I-, blade, -and hat-shapeed stiffeners were investigated. In the analysis, the stiffened panels were anlyzed using the nonlinear finite element method combined with an improved arc-length method. The progressive failure analysis was done by adopting the maximum stress criterion and complete unloading failure model. The effects of the fiber angles were investigated on the buckling and postbuckling behaviors. In the experiment, the web and the lower cap of each stiffener were formed by the continuous lay-up of the skin for cocuring the stiffened panels. Therefore, the separation between stiffener and skin was not found in the junction part even after postbuckling ultimate load and the stiffened panels had excellent postbuckling load carrying capacity. A shadow moire thchnique was used to monitor the out-of-plane deformations of the panels. The piezoelectric films were attached to the panels to get the failure characteristics of the panel. The analytical results on the buckling load, postbuckling ultimate load, and failure pattern showed good agreement with the experimental results.

Buckling Loads and Postbuckling Behavior of Tapered Piles by Third Order Theory (3차이론에 의한 변단면 강말뚝의 좌굴하중및 후좌굴 거동)

  • 이병구;정진섭;이문수;박승해
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.36 no.2
    • /
    • pp.56-66
    • /
    • 1994
  • Numerical methods are developed to obtain the buckling loads and to analyze the postbuckling behavior of the tapered steel piles. The nondimensional differential equations governing the elastica of the buckled piles are derived by the third order theory and solved numerically. The Runge-Kutta method is used to solve the differential equations, and the bisection method is used to obtain the buckling loads and the reaction moments of the clamped ends. Both the linear and stepped taper of the steel piles are considered as the variable crosssection in the differential equations. As the numerical results, the equilibrium paths, the buckling loads vs. section ratio curves and the typical elastica and the bending moment diagrams of the buckled piles are presented in figures. Experimental studies that complement the theoretical results are presented. It is expected that the numerical methods developed in this study for calculating the buckling loads and analyzing the postbuckling behavior of the steel piles are used in the structural and foundation engineering.

  • PDF