• Steel and Composite Structures
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• v.21 no.1
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• pp.37-55
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• 2016

In this study, the influence of centrally placed circular and square cutouts on vibration and buckling characteristics of different ply-oriented laminated panels under the action of compressive and/or tensile types of non-uniform in-plane edge loads are investigated. The panels are inspected under the action of uniaxial compression, uniaxial tension and biaxial, compression-tension, loading configurations. Furthermore, the effects of different degrees of edge restraints and panel aspect ratios are also addressed in this work. Towards this, a nine-node heterosis plate element has been adopted which includes the effect of shear deformation and rotary inertia. According to the results, the tensile buckling loads are higher than that of compressive buckling loads. However, the tensile buckling load continuously reduces with the increased cutout sizes irrespective of ply-orientations. This is also true for compressive buckling loads except for some particular ply-orientations with higher sized cutouts.

• Structural Engineering and Mechanics
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• v.6 no.7
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• pp.827-839
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• 1998

This paper presents a study of buckling of the multi-vaulted cylindrical shell ("Aster"), under an axial compression alone or combined with an external pressure. This shell which was presented in a recent paper is a self-stiffened structure having a satisfactory behaviour and a higher buckling strength under external pressure than a circular cylindrical shell with the same dimensions. The results of this study emphasize the interest of the behaviour of the "Aster" shell under two other types of loading, revealing an acceptable level of strength which is favorable for an expansion of its use in other areas.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.5
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• pp.150-156
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• 2000

The objective of this study is to investigate effects of prebuckling on the buckling of laminated composite cylindrical shells. Axial compression and lateral pressure are considered for laminated composite cylindrical shells with the ratios of length to radius. The shell walls are made of a laminate with several symmetric ply orientations. The study was made using finite difference energy method, utilizing the nonlinear bifurcation branch with nonlinear prebuckling displacements. The results are compared to the buckling loads determined when membrane prebuckling displacements are considered. Review the influence of nonlinear prebuckling for the buckling loads, the difference between the actual and classical buckling loads are increased as the increments with the ratios of length to radius, for which is applied the axial compression, but almost same for the lateral pressure.

• Structural Engineering and Mechanics
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• v.4 no.2
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• pp.163-176
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• 1996

The tension and compression buckling behaviour of a square plate with localized zones of damage and subjected to non-uniform loading is studied using a finite element analysis. The influence of parameters such as position of damage, extent of damage, size of damage and position of load on instability behaviour are discussed. The dynamic behaviour for certain load and damage parameters are also presented. It is observed that the presence of damage has a marked effect on the static buckling load and natural frequency of the plate.

• Steel and Composite Structures
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• v.3 no.4
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• pp.261-275
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• 2003

Truss members built-up with double angles back-to-back have monosymmetric cross-section and twisting always accompanies flexion upon the onset of buckling about the axis of symmetry. Approximate formulae for calculating the buckling capacity are presented in this paper for routine design purpose. For a member susceptible only to flexural buckling, its optimal cross-section should consist of slender plate elements so as to get larger radius of gyration. But, occurrence of twisting changes the situation owing to the weakness of thin plates in resisting torsion. Criteria for limiting the leg slenderness are discussed herein. Truss web members in compression are usually considered as hinged at both ends for out-of-plane buckling. In case one (or both) end of member is not supported laterally by bracing member, its adjoining members have to provide an elastic support of adequate stiffness in order not to underdesign the member. The stiffness provided by either compression or tension chords in different cases is analyzed, and the effect of initial crookedness of compression chord is taken into account. Formulae are presented to compute the required stiffness of chord member and to determine the effective length factor for inadequately constrained compressive diagonals.

• Structural Engineering and Mechanics
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• v.66 no.6
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• pp.737-748
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• 2018

The current study presents a new technique in the framework of the nonlocal elasticity theory for a comprehensive buckling analysis of Euler-Bernoulli nano-beams made up of bidirectional functionally graded material (BDFGM). The mechanical properties are considered by exponential and arbitrary variations for axial and transverse directions, respectively. The various circumstances including tapering, resting on two-parameter elastic foundation, step-wise or continuous variations of axial loading, various shapes of sections with various distribution laws of mechanical properties and various boundary conditions like the multi-span beams are taken into account. As far as we know, for the first time in the current work, the buckling analyses of BDFGM nano-beams are carried out under mentioned circumstances. The critical buckling loads and mode shapes are calculated by using energy method and a new technique based on calculus of variations and collocation method. Fast convergence and excellent agreement with the known data in literature, wherever possible, presents the efficiency of proposed technique. The effects of boundary conditions, material and taper constants, foundation moduli, variable axial compression and small-scale of nano-beam on the buckling loads and mode shapes are investigated. Moreover the analytical solutions, for the simpler cases are provided in appendices.

• Journal of Korean Association for Spatial Structures
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• v.4 no.1 s.11
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• pp.77-86
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• 2004

It is the buckling of the compression portions of the deckplate that govern its behaviour under wet concrete construction loading. The size and position of intermediate stiffeners in the compression flanges of thin-plate steel decks exert a strong influence on the dominant buckling mode of the flange. Test sections composed of high-strength steel were brake pressed with a variety of Flat-hat intermediate stiffeners in the compression flange forming a progression from small to large stiffeners. The ABAQUS program to determine the effectiveness of intermediate stiffeners in controlling buckling modes is undertaken. A series of specimens are loaded with simple beam. Various buckling wave forms prior to ultimate failure through a plastic collapse mechanism. The experimentally determined buckling stresses are found to be comparable with studies performed using the ABAQUS program analysis and using each country code.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.223-227
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• 2004

The pultruded structural shapes are usually composed of thin-walled plate elements. Because the composite material has relatively low elastic moduli, the design of pultruded compression members may not be governed by the material strength limit state but by the stability limit state such as the local buckling or the global buckling. Therefore, the stability limit state must be checked to design pultruded columns. In this research, the local buckling analysis of pultruded I-shape column was conducted for various composite materials using the closed-form solution. To establish the design guidelines for the local buckling of pultruded I-shape compression members, the simplified form of equation to find the local buckling coefficient of pultruded I-shape column was proposed as a function of mechanical properties and the width ratio of plate components using the results obtainde by the closed-form solution. In order to verify the validity of proposed solution, the results obtained by the proposed approximate solution were compared with those of the closed-form solution and the experimental results.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.260-266
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• 2018

Cylindrical shells are often used in the construction of ship and land-based structures such as deck plating with a camber, side shell plating for fore and aft part pipes, as well as storage tanks. It has been believed that such curved shells can be modeled fundamentally as a part of the cylinder under axial compression. From the estimations made based on cylindrical models, it is known that in general, curvature increases the buckling strength of a curved shell when subjected to axial compression, and the same curvature is also expected to increase the overall strength. A series of elastic large deflection analyses were conducted in order to clarify the fundamentals observed in the buckling and post-buckling behaviour of circular cylinders under axial compression. In the present paper, an FE-series analysis has been performed based on the elastic large deflection behaviour, and the effect of parameters has been clarified. The ultimate strength behavior of the circular cylinder was found to be significantly influenced by both the initial deflection and the FE-modeling method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.790-793
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• 2001

The characteristics of smart skin for wireless LAN system under compression load are investigated. The smart skin structure is composed of 3 layers of face material and 2 layers of core material. Theoretical formula for determining buckling load is derived by Rayleigh-Ritz method and compared with experimental result. The maximum length of specimen that buckling does not occur is determined by assuming that the compression load is sustained by only face material. In the experiment, if buckling occurs obviously then it follows the theoretical result well. In the process of buckling, the load supporting capability and the antenna property such as radiation pattern and reflection coefficient were examined.