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Journal ArticleDOI

Some studies on buckling of laminated composite thin walled box beams

03 Dec 1997-Composite Structures (Elsevier)-Vol. 40, pp 267-275
TL;DR: In this article, the effect of number of layers, lay-up sequence and fiber angle on the buckling load was studied for symmetric and anti-symmetric lay-ups.
About: This article is published in Composite Structures.The article was published on 1997-12-03. It has received 8 citations till now. The article focuses on the topics: Buckling & Composite number.
Citations
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Journal ArticleDOI
TL;DR: In this article, a combination of Elitist-Genetic algorithm (E-GA) and finite strip method (FSM) was used for fundamental frequency optimization of symmetric laminated composite plates.
Abstract: In the present paper, fundamental frequency optimization of symmetrically laminated composite plates is studied using the combination of Elitist-Genetic algorithm (E-GA) and finite strip method (FSM). The design variables are the number of layers, the fiber orientation angles, edge conditions and plate length/width ratios. The classical laminated plate theory is used to calculate the natural frequencies and the fitness function is computed with a semi-analytical finite strip method which has been developed on the basis of full energy methods. To improve the speed of the optimization process, the elitist strategy is used in the Genetic algorithm. The performance of the E-GA is also compared with the simple genetic algorithm and shows the good efficiency of the E-GA algorithm. A multi-objective optimization strategy for optimal stacking sequence of laminated box structure is also presented, with respect to the first natural frequency and critical buckling load, using the weighted summation method to demonstrate the effectiveness of the E-GA. Results are corroborated by comparing with other optimum solutions available in the literature, wherever possible.

39 citations


Additional excerpts

  • ...The strip stiffness matrix in global system is given by: [k̄e] = [T ][ke][T ]T (11a) [k̄g] = [T ][kg][T ]T (11b) [m̄e] = [T ][me][T ]T (11c) where [T ] is the transformation matrix [22]....

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Journal ArticleDOI
TL;DR: In this article, a general analytical model applicable to the flexural, torsional and flexural-torsional buckling of a thin-walled composite box beam subjected to axial load is developed.
Abstract: Buckling of an axially loaded thin-walled laminated composite is studied. A general analytical model applicable to the flexural, torsional and flexural–torsional buckling of a thin-walled composite box beam subjected to axial load is developed. This model is based on the classical lamination theory, and accounts for the coupling of flexural and torsional modes for arbitrary laminate stacking sequence configuration, i.e. unsymmetric as well as symmetric, and various boundary conditions. A displacement-based one-dimensional finite element model is developed to predict critical loads and corresponding buckling modes for a thin-walled composite bar. Governing buckling equations are derived from the principle of the stationary value of total potential energy. Numerical results are obtained for axially loaded thin-walled composites addressing the effects of fiber angle, anisotropy and boundary conditions on the critical buckling loads and mode shapes of the composites.

28 citations


Cites background from "Some studies on buckling of laminat..."

  • ...Suresh and Malhotra [7] studied buckling of laminated composite thin-walled rectangular box beam configurations....

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Journal ArticleDOI
TL;DR: In this article, an overview of the buckling and postbuckling behavior of thin-walled composite laminated beams is provided, covering topics such as exact and closed-form analytical approximate solutions as well as semi-analytical and numerical methods.
Abstract: Thin-walled beams made of laminated composite materials are increasingly used in any engineering branch where structural weight is one of the major aspects in the design process of load bearing structures. Quite naturally, when composite materials are being employed analysis methods are required that adequately take effects such as material anisotropy, coupling effects, shear deformations, and the like into account which are inherent to this class of materials. This paper aims to provide an overview of engineering analysis methods concerning the buckling and postbuckling behaviour of thin-walled composite laminated beams, covering topics such as exact and closed-form analytical approximate solutions as well as semi-analytical and numerical methods wherein a distinction is made between local and global buckling of beam structures, and the interaction of global and local buckling modes. This paper also covers an overview of experimental investigations as well as of design optimization studies and closes with an outlook on future investigations.

18 citations

Journal ArticleDOI
TL;DR: In this article, a coupled stability analysis of thin-walled composite beam with closed cross-section subjected to various forces such as eccentric constant axial force, end moments, and linearly varying axial forces is presented.
Abstract: For the coupled stability analysis of thin-walled composite beam with closed cross-section subjected to various forces such as eccentric constant axial force, end moments, and linearly varying axial force, the efficient numerical method to evaluate the element stiffness matrix is newly presented based on the homogeneous form of simultaneous ordinary differential equations. The general bifurcation type of buckling theory for thin-walled composite box beam is developed based on the energy functional corresponding to semitangential rotations and semitangential moments. The coupled stability equations including variable coefficients and the force–displacement relationships are derived from the energy principle and explicit expressions for displacement functions are presented based on power series expansions of displacement components. The element stiffness matrix is evaluated by applying member force–displacement relationships to these displacement functions. In addition, the finite element model based on the cubic Hermitian interpolation polynomial is presented. In order to verify the accuracy and validity of this study, numerical solutions are presented and compared with the finite element solutions using the Hermitian beam elements and the available results from other researchers. Particularly, the influence of the eccentricity and the force ratio of axial forces, the fiber orientation, and the boundary conditions on the buckling behavior of composite box beam are parametrically investigated. Also the emphasis is given in showing the phenomenon of buckling mode change.

18 citations

Journal ArticleDOI
TL;DR: In this article, the authors present an alternative technological solution for passive earthquake control of shear building structures, where the viscoelastic material is modelled as a linear solid-type material to present the damping characteristics.
Abstract: This paper presents an alternative technological solution for passive earthquake control of shear building structures. For this purpose, new two nodes with ten DOF per node finite element is formulated for dynamic analysis of sandwich box column with viscoelastic material as core layer under torsion and bending effects. The viscoelastic material is modelled as a linear solid-type material to present the damping characteristics. Dynamic equilibrium equations are written in time domain and they are resolved numerically by adopting the time step-by-step Newmark numerical integration method, in conjunction with trapezoidal rule to compute the integration term of the dynamic equation. The influences of the boundary conditions to reduce the tip displacements and accelerations of a one storey building under seismic loads as far as possible are discussed.

14 citations

References
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Book
01 Jan 1936

8,152 citations

Book
01 Jan 1976
TL;DR: Numerical methods in finite element analysis, Numerical techniques in finite elements analysis, and so on.
Abstract: Numerical methods in finite element analysis , Numerical methods in finite element analysis , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

2,085 citations

Book
01 Jan 1975

1,449 citations

Journal ArticleDOI
TL;DR: In this article, a simple extension is made which allows the element to be economically used in all situations by reducing the order of numerical integration applied to certain terms without sacrificing convergence properties.
Abstract: The solution of plate and shell problems by an independent specification of slopes and middle surface displacements is attractive due to its simplicity and ability of reproducing shear deformation. Unfortunately elements of this type are much too stiff when thickness is reduced. In an earlier paper a derivation of such an element was presented1 which proved very successful in ‘thick’ situations. Here a very simple extension is made which allows the element to be economically used in all situations. The improved flexibility is achieved simply by reducing the order of numerical integration applied to certain terms without sacrificing convergence properties. The process is of very wide applicability in improvement of element properties.

1,336 citations

Journal ArticleDOI
Abstract: A review of the recent developments in the analysis of laminated beams and plates with an emphasis on shear effects and buckling is presented. A discussion of various shear-deformation theories for plates and beams is given. The available theories are derived assuming a variation of either the in-plane displacement components or the stress components or both in the thickness coordinate. A review of the recently developed finite elements to analyze thin and thick laminated beams and plates is given next. These elements have been derived using the displacement methods, or the mixed methods or the hybrid methods. Recent studies on the buckling and postbuckling behavior of perfect and geometrically imperfect plates are described next. These behaviors have been studied using analytical, numerical, and experimental techniques. Finally, a review of the various studies on the delamination buckling and growth in beams and plates is given. Once again, the studies have been conducted using analytical, numerical, and experimental techniques. The energy release rates have been determined using closed-form solutions or using numerical differentiation. Mention also is made of studies on multiple delaminations and on dynamic response of composite laminates under impact loads.

490 citations