• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.2
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• pp.23-28
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• 1998

In this paper, the experimental and numerical results of buckling loads for laminated composite plates are compared. Using boundary conditions of buckling test are all fixed supports. Experiments were conducted for plates with fiber angles $ heta$=30$^{\circ}$, 45$^{\circ}$,60$^{\circ}$ and aspect ratio a/b=0.8. Experimental results were obtained from load-deflection curves of buckling test. Numerical methods were presented to evaluate buckling loads, using structural analysis results from ANSYS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.65-74
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• 1993

The buckling load of a blade stiffened laminated composite plate having midplane symmetry is maximized for a given total weight. The thicknesses of the layers and the width and height of the stiffener are taken as the design variables. Buckling analysis is carried out using a finite element method. The optimization problem is solved using an IMSL subroutine. Due to the highly nonlinear nature of the optimality equations, several local optimum solutions are found. Various combinations of fiber orientation for the laminate layers and the blade stiffener are investigated to examine their relative efficiency. Out of several cases examined, the best design was produced from the combination of ($0^{\circ}Beam/0^{\circ}/90^{\circ}$)s.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.169-181
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• 1991

In this study, an analytical solution of pre-buckling, buckling, post-buckling, ultimate strength and post-ultimate strength behaviour of simply supported rectangular plates subjected to biaxial compression is derived. Parametric study with varying the aspect ratio, the slenderness ratio and the loading ratio is carried out. The present solution may be used as basical data when the verfication of the numerical and experimental result is made.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.10-19
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• 2014

Corrugated steel plates are made by fabricating thin steel plates to have trapezoidal or sinusoidal corrugation, and the corrugated plates are able to maintain high out-of-plane rigidity even when they are used instead of thick flat plates. Also, corrugated steel plates have almost no axial rigidity due to the accordion effect. Thus, if they are applied to the webs of plate girders, designing can be easily conducted so that the webs bear only shear stresses. However, unlike flat plates, the shear buckling of corrugated steel plates has very complex characteristics where buckling occurs due to the interaction of local and global buckling, besides local buckling and global buckling. For the investigation of the cause and characteristics of this interactive buckling, studies on sinusoidal corrugated steel plates are fewer than studies on trapezoidal corrugated steel plates. Therefore, in this study, the shear buckling characteristics of sinusoidal corrugated steel plates and the occurrence pattern of interactive buckling were investigated. For the calculation of shear buckling strength, a finite element program was used, and the analysis results were compared with the exact solution. In addition, the characteristics of buckling stress change and the change of buckling mode shape depending on corrugation thickness and shape parameter were analyzed, and by comparing these results with the results of a theoretical equation, the timing of buckling mode change was analyzed.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.191-196
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• 1999

This stability of a plate structure is very crucial problem which results in wrinkle and bucking. In this study, the effect of the pattern of spot-welding points of the two rectangular plates on the compressive buckling load is studied with respect to the thickness, aspect ratio of plates, number of welding spots. buckling coefficient of the plate not welded was compared with that of two plates with various thickness to extract the effect of thickness. The effect of number of welding spots are studied in tow directions, longitudinal and transverse directions. The conclusions obtained were that the reinforcement effect was maximized when the aspect ratio was close to 1.25 and that the effect of number of welding spots in transverse direction was large than that in longitudinal direction.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.3
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• pp.56-65
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• 1996

Recently, with development of mechanics of materials, as pursuing the high speed of the ships, there has been an increasing demand on the composite construction which satisfies high strength and low weight at the same time. A sandwich element is a type of composite construction, which is composed of thin, strong, stiff and relatively high density faces and a thick, light, and weaker core material. As the second moment is increased by faces separated from the neutral axis farther, a sandwich element is most effective light structural form. In this study, Rayleigh-Ritz Energy Method is adopted, which can analyze sandwich plate relatively simply and exactly. Stresses and buckling loads are analyzed exactly, when uniform lateral pressure load, inplane compression and inplane shear are acting at the sandwich plate. Including a wrinkling stress, this study can be applied to the initial design and minimum weight design of sandwich plates.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.265-272
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• 2007

The finite element linear buckling analysis of folded plate structures using adaptive h-refinement methods is presented in this paper. The variable-node flat shell element used in this study possesses the drilling D.O.F. which, in addition to improvement of the element behavior, permits an easy connection to other elements with six degrees of freedom per node. The Box-typed structures can be analyzed using these developed flat shell elements. By introducing the variable-node elements some difficulties associated with connecting the different layer patterns, which are common in the adaptive h-refinement on quadrilateral mesh, can be overcome. To obtain better stress field for the error estimation, the super-convergent patch recovery is used. The convergent buckling modes and the critical loads associated with these modes can be obtained.

• Composites Research
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• v.27 no.4
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• pp.158-167
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• 2014

Final goal of this research is to establish the database for correlation factors which connects the test and analysis results of shear buckling allowables for composite plate. To accomplish the goal, extensive test and analysis works are required. In this paper, as the first step, a frame-type fixture for shear buckling test was designed and validated through the test and analysis. Final configuration of the fixture were determined via parametric study on the effect of specimen size, cross-sectional dimensions, and number of fastening bolts on the shear buckling load. Results of the study showed the designed frame-type fixture successfully induces the shear buckling of composite plate. However, there were deviations between the test results and analysis results for ideal case under pure shear load, which were mainly caused by the difference in plate sizes for both cases. The difference were larger in the plates with larger hole and simply supported boundary condition. It is concluded from the results that while the designed fixture can be used for the clamped plates with acceptable accuracy, it shows larger difference in the simply supported plates.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.714-721
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• 2018

In this study, we investigate a design technology intended to radically increase the buckling strength of vertically curved panels. Recent studies proposed a buckling strength formula which properly reflects the effect on the local plate buckling strength of flat plates when they are stiffened by closed section ribs. Herein, we attempted to quantitatively evaluate this effect on curved panels and to reveal the correlations with the design parameters. The commercial finite element software, ABAQUS, was used to build a three dimensional numerical model and numerical parametric studies were conducted to evaluate the variation of the buckling strength. In the case of flat panels, the local buckling strength of stiffened curved panels increases proportionally with increasing rotational stiffness of the closed-section ribs. After attaining a limiting value, an obvious tendency was found that the local buckling strength of the stiffened curved panel would converge towards a fixed value when the panels are supported along both sides. The parametric studies performed using the influential design parameters confirmed that the estimated partially-restrained curved panel strength is well correlated with the proposed formula.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.12
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• pp.54-59
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• 2001

The stability of a thin plate structure is very crucial problem which results buckling. Because the buckling strength of thin plates is lower than the yield strength of the material, reinforcement plate must be used to increase the buckling strength. And, in this case, spot welding is commonly used, however, the spot welded joints are practically designed by experimental decisions, so it is Inefficient and has the risks of buckling demolition. In this study, two parameters, such as the area ratio and the distance ratio of spot welding which have influence on the buckling strength, should be chosen. Under compressive and shearing load, the effect of two parameters on the critical stress is discussed.