• Journal of Korean Society of Steel Construction
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• v.14 no.5 s.60
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• pp.665-674
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• 2002

The back-to-back and box-shaped headers used in light gauge steel structures have some disadvantages, i.e., construction efficiency and cost competitiveness. As such, cold-formed steel L-shaped headers have been developed and are used actively in advanced nations. However, this system has not been used in Korea because of inadequate investigation and adaptation efforts and lack of application example. Thus, this research evaluated the structural performance of L-header using buckling analyses and bending tests. Test results were compared using the AISI design criteria. Test results showed that local buckling and distortional buckling governed buckling behavior in gravity loads and uplift loads, respectively. These results were consistent with the calculated nomial strengths using the AISI design criteria.

• Steel and Composite Structures
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• v.30 no.5
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• pp.471-481
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• 2019

Beam-columns are structural members subjected to a combination of axial and bending forces. Lateral-torsional buckling is one of the main failure modes. Beam-columns that are bent about its strong axis may buckle out of the plane by deflecting laterally and twisting as the values of the applied loads reach a limiting state. Lateral-torsional buckling failure occurs suddenly in beam-column elements with a much greater in-plane bending stiffness than torsional or lateral bending stiffness. This study intends to establish a unique convenient closed-form equation that it can be used for calculating critical elastic lateral-torsional buckling load of beam-column in the presence of a known axial load. The presented equation includes first order bending distribution, the position of the loads acting transversely on the beam-column and mono-symmetry property of the section. Effects of axial loads, slenderness and load positions on lateral torsional buckling behavior of beam-columns are investigated. The proposed solutions are compared to finite element simulations where thin-walled shell elements including warping are used. Good agreement between the analytical and the numerical solutions is demonstrated. It is found out that the lateral-torsional buckling load of beam-columns with mono-symmetric sections can be determined by the presented equation and can be safely used in design procedures.

• Structural Engineering and Mechanics
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• v.91 no.4
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• pp.417-426
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• 2024

Nanotechnology has emerged as a promising avenue for enhancing musical structures. In this study, we analyze the static behavior of laser harp (i.e., electronic musical instrument) reinforced with Zinc Oxide (ZnO) nanoparticles. Leveraging the piezoelectric properties of ZnO nanoparticles, the structure is subjected to an electric field for intelligent control. The electronic musical structure is situated in a foundation with vertical springs and shear modulus constants. We employ the exponential Shear Deformation Beam Theory (ESDBT) to mathematically model the structure. A micro-electro-mechanical model is employed to determine the equivalent properties of the system. By utilizing nonlinear stress-strain relations, energy methods, and Hamilton's principle, we derive the motion equations. The buckling load of the electronic musical beam is calculated using the Difference Quadrature Method (DQM). The primary objective of this study is to present a mathematical model for electronic musical beams and determining the buckling load of the structure and to investigate the influence of nanotechnology and electric fields on its buckling behavior. The buckling is the case when the structure becomes deforms and unstable. Our findings reveal that the application of negative external voltage to the electronic musical structure increases both the stiffness and the buckling load of the musical system. Furthermore, reinforcing the electronic musical structure with ZnO nanoparticles results in an increased buckling load. Notably, the maximum enhancement in the 28-day compressive and tensile strengths of samples containing zinc oxide nanoparticles compared to the control sample resulting in increases of 18.70% and 3.77%, respectively.

• Steel and Composite Structures
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• v.29 no.1
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• pp.39-51
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• 2018

Position of a circular or elliptical cutout within an orthotropic plate has great influence on its buckling behavior. This paper aims at finding the optimal position (both location and orientation) of a single circular/elliptical cutout, within an orthotropic rectangular plate, that maximizes the critical buckling load. We consider linear buckling of simply supported orthotropic plates under uniaxial edge loads. To obtain the optimal positions of the cutouts, we have employed a MATLAB optimization routine coupled with buckling computation in ANSYS. Our results show that the position of the cutout that maximizes the buckling load has great dependence on the material properties, laminate configurations, and the geometrical parameters of the plate. These optimal results, for a number of plate geometries and cutout sizes, are reported in this paper. These results will be useful in the design of perforated orthotropic plates against buckling failure.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1520-1534
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• 1994

A new analytical method for the prediction of the buckling behavior of laminated plates consisting of layers having different properties in tension and compression, so called bimodulus, is proposed in this paper. Buckling analysis of bimodular composite laminated paltes are performed with the results reduced from plate bending analysis. The governing equations of bimodular plates are based on the first shear deformation theory. As a case study, bending and buckling of simply supported, multilayered, symmetric, antisymmtric, and specially orthotropic laminates under uniformly distributed lateral load for bending analysis and in-plane load for buckling are considered. The results of the bending analysis are compared with the previous papers. Then, the fundamental critical buckling loads and buckling modes are calculated for the various bimodular composite rectangular thin plates.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.759-763
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• 2006

Cable Stayed Bridge is mainly composed of three element. Composed element are cable. stiffening girder and Pylon. The characteristic of bridge's behavior depend on these three element's relative stiffness, shape and system of bridge. The purpose of this paper is to exame the characteristic of bridge's behavior and buckling strength of stiffening girder according to shape and flexure stiffness of pylon

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.129-139
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• 2005

The focused topic according to be slender and longer of cable stayed bridge's main span is as follows (1) Aerodynamic stability (2) Lateral movement of stiffening girder caused by wind force during and after construction (3) Global bucking of stiffening girder caused by axial force Among this, the number 3 has not received much attention in the past due to high buckling safety factor of stiffening girder. However, according to be slender of stiffening girder, the topic of buckling stability of girder is not any more unconcerned subject. The purpose of this paper is to examine the effect of stay cable's nonlinear behavior on the buckling stability of cable-stayed bridge.

• 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.

• Composites Research
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• v.12 no.3
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• pp.17-25
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• 1999

In this paper, we present the analytical study results of buckling behavior of elastically restrained orthotropic plates. In the study the boundary conditions of the plate are simply supported at all four edges and elastically restrained by the elastic medium at opposite two longitudinal edges. The energy method is employed in the solution of the problems in which method the buckling coefficient is calculated from the condition that the work-done by the external forces during buckling is equal to the stored elastic strain energy. The results are presented in the graphical from. The equations derived for the orthotropic plate in this study are compared with existing isotropic ones and identical results were observed.

• Structural Engineering and Mechanics
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• v.51 no.6
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• pp.1017-1036
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• 2014

Steel tubes have an efficient shape with large second moment of inertia relative to their light weight. One of the main problems of these members is their low buckling resistance caused from having thin walls. In this study, steel foams with high strength over weight ratio is used to fill the steel tube to beneficially modify the response of steel tubes. The linear eigenvalue and plastic collapse FE analysis is done on steel foam filled tube under pure compression and three point bending simulation. It is shown that steel foam improves the maximum strength and the ability of energy absorption of the steel tubes significantly. Different configurations with different volume of steel foam and composite behavior is investigated. It is demonstrated that there are some optimum configurations with more efficient behavior. If composite action between steel foam and steel increases, the strength of the element will improve, in a way that, the failure mode change from local buckling to yielding.