• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.91-94
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• 2001

This paper presents the analytical investigation pertaining to the local buckling behavior of orthotropic channel section compression members stiffened with unsymmetric stiffeners at its free edges. In the analysis, tile edge stiffener is modeled as a beam element or a plate element. The result of both cases is presented in graphical form so that the effects of edge stiffeners on the local buckling strength of edge stiffened channel section member can be found.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.429-434
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• 2002

The differential equations governing in-plane free vibrations of stepped circular arcs, including the effects of axial deformation, rotatory inertia and shear deformation, are derived and solved numerically to obtain frequencies and mode shapes. Numerical results are calculated for the clamped-clamped symmetric and unsymmetric circular arcs with thickness varying in a discontinuous fashion. The lowest four natural frequencies and mode shapes are presented over a range of non-dimensional system parameters: the subtended angle, the slenderness ratio, the section ratio and the ratio of discontinuous section.

• Journal of the Korean Statistical Society
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• v.31 no.4
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• pp.533-543
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• 2002

In this paper we propose a change-point estimator with left and right regressions using the sample Fourier coefficients on the orthonormal bases. The window size is different according to the data in the left side and in the right side at each point. The asymptotic properties of the proposed change-point estimator are established. The limiting distribution and the consistency of the estimator are derived.

• Journal of Aerospace System Engineering
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• v.1 no.4
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• pp.28-36
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• 2007

This paper presents critical buckling loads of laminated composites under cylindrical bending. In-plane displacements are assumed to vary exponentially through plate thickness. The accuracy of this theory is examined for symmetric/antisymmetric cross-ply, angle-ply and unsymmetric laminates under cylindrical bending. Analytical solutions are provided to investigate the effect of transverse shear deformation on critical buckling loads of the laminated plates, and the results are compared with those obtained from the first-order shear deformation plate theory and the classical laminated plate theory.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4A
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• pp.217-225
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• 2012

Structural behavior of built-up compression members with unsymmetric connectors under buckling status has been studied through these experiments. When the distance between adjacent H-300 beams of built-up compression member is 2 m in length, and the H-300 beams are lengthened up to 30 m in length with three-10 m-H-beams by bolts and double arrayed, three specimen having each connector plate, single channel, double channel are experimented for evaluating buckling loads. The buckling loads from the experiments are compared with buckling loads of structural analysis using FEM and buckling loads of Timoshenko Eq. in order to figure out how the connectors' type affects on longitudinal and lateral displacements, also strain of the built-up compression members as well. The result from the experiments show that the buckling loads 4.2% decreases in double channel connectors and 36.6% decreases in single channel connectors than plate connectors.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.39-52
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• 1993

For the lateral-torsional buckling analysis of the thin-walled space frame and circular arch with the unsymmetric cross section, the tangent stiffness matrices are derived by introducing Vlasov's assumption for the thin-walled beam and using the principle of virtual displacement. In the cases of the unrestrained torsion and the restrained torsion, the elastic and geometric stiffness matrices corresponding to semitangential rotation and semitangential moment are evaluated by using the Hermitian polynomials as the shape function. In order to illustrate the accuracy and convergence characteristics of the derived formulations, numerical examples for the lateral-torsional buckling analysis of the hinged circular arch under pure bending and uniform compression are presented and compared with the analytic solutions of references.

• Journal of Korean Society of Steel Construction
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• v.28 no.1
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• pp.43-52
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• 2016

A numerical study on required stiffness of the longitudinal stiffener in the webs stiffened with flat plate at one-side of the web was conducted. The longitudinal stiffeners are commonly placed around 0.2D, i.e., 1/5 the web depth due to fabrication convenience although most plate girders for bridges are unsymmetric section. Considering asymmetry of section, aspect ratio of web and the rigidity ratio of longitudinal stiffener(${\gamma}^*$), eigenvalue analysis were performed to evaluate the buckling strength for the webs with a stiffener located at 0.16D~0.24D. Based on the parametric analysis, the required stiffness of the longitudinal stiffener to satisfy the buckling strength specified in AASHTO LRFD specifications was presented.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.970-978
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• 2002

The differential equations governing free vibrations of the elastic arches with unsymmetric axis are derived in Cartesian coordinates rather than in polar coordinates. in which the effect of rotatory inertia is included. Frequencies and mode shapes are computed numerically for parabolic arches with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. The convergent efficiency is highly improved under the newly derived differential equations in Cartesian coordinates. The lowest four natural frequency parameters are reported, with and without the rotatory inertia, as functions of three non-dimensional system parameters the rise to chord length ratio. the span length to chord length ratio, and the slenderness ratio. Also typical mode shapes of vibrating arches are presented.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.138-145
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• 2013

A sweep-based heuristic using common area is developed for multi-vehicle VRPs under time various and unsymmetric forward and backward vehicle moving speed. One depot and 2 delivery vehicle are assumed in this research to make the problem solving strategy simple. A common area is held to make adjustment of possible unbalance of between two vehicle delivery completion times. The 4 time zone heuristic is used to solve for efficient delivery route for each vehicle. The current size of common area needs to be studied for better results, but the suggested problem solving procedures can be expanded for any number of vehicles.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.990-1004
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• 1995

A modified 16-node element for composite plate has been proposed and compared with the 20-node element to check the validity of it. The fields of numerical inspection include mode analysis and specific damping analysis. By symetrizing the conventional unsymmetric damping matrix in the analysis of specific damping capacity, we could compute the specific damping capacity and make a program, effectively. In addition, we could predict the errors caused by reduction of integration order in thickness direction depending upon the number of layers.