• Structural Engineering and Mechanics
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• v.84 no.3
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• pp.423-435
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• 2022

In this article, we present torsion-bending analysis of a composite FGM beam with an open section, according to the advanced and refined theory of 1D / 3D beams based on the 3D Saint-Venant's solution and taking into account the edge effects. The (initially one-dimensional) model contains a set of three-dimensional (3D) displacement modes of the cross section, reflecting its 3D mechanical behaviour. The modes are taken into account depending on the mechanical characteristics and the geometrical form of the cross-section of the composite FGM beam. The model considered is implemented on the CSB (Cross-Section and Beam Analysis) software package. It is based on the RBT/SV theory (Refined Beam Theory on Saint-Venant principle) of FGM beams. The mechanical and physical characteristics of the FGM beam continuously vary, depending on a power-law distribution, across the thickness of the beam. We compare the numerical results obtained by the three-beam theories, namely: The Classical Beam Theory of Saint-Venant (Classical Beam Theory CBT), the theory of refined beams (Refined Beam Theory RBT), and the theory of refined beams, using the higher (high) modes of distortion of the cross-section (Refined Beam Theory using distorted modes RBTd). The results obtained confirm a clear difference between those obtained by the three models at the level of the supports. Further from the support, the results of RBT and RBTd are of the same order, whereas those of CBT remains far from those of higher-order theories. The 3D stresses, strains and displacements, obtained by the present study, reflect the 3D behaviour of FGM beams well, despite the initially 1D nature of the problem. A validation example also shows a very good agreement of the proposed models with other models (classical or higher-order beam theory) and Carrera Unified Formulation 1D-beam model with Lagrange Expansion functions (CUF-LE).

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.123-128
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• 2002

In this paper, an averaged constitutive model of concrete and reinforcing bars for RC structure and path-dependent Ohsaki's model for soil are applied, and an elasto-plastic interface model having thickness is preposed for seismic analysis of underground RC subway station structure. A finite element analysis technique is developed by applying aforementioned constitutive equations and verified through seismic analysis of underground RC subway station. Then, failure mechanisms of the RC subway station structure under seismic action are numerically derived. Then, failure modes and damage levels of the station are also analytically evaluated for the cases of several designs of the underground RC station.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.34-39
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• 1995

Particle displacement distributions of the fundamental mode and overtone modes in an energy-frapped single resonator and an energy-trapped double acoustically coupled filter using the thickness shear vibration were calculated. And the effects of the width of a pair of partial electrodes, the width of the gap between two pairs of partial electrodes and the magnitude of the plate back on the displacement distributions of the symmetric vibration mode and anti-symmetric vibration mode of the resonators and the filters were investigated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.265-272
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• 1997

In this paper the bending collapse characteristics of 60 series Al rectangular tubes were studied with a pure bending collapse test rig which could apply the pure bending moment, there occured three kinds of bending collapse modes - local buckling, delayed buckling, tensile failure - depending on the b/t(width/thickness) ratio and material properties. Experiment results are compared with the results of finite element method.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.316-320
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• 2000

An ultrasonic linear motor was composed of a slider and a stator vibrator including piezoelectric material and elastic material. The ultrasonic linear motors mainly consist of an ultrasonic oscillator which generates elliptical oscillations. Elliptical oscillations are generated by synthesizing two degenerated modes. The design of a stator for an Ultrasonic linear motor was optimized with respect to vibration mode and direction of vibratory displacement by employing the finite element method. The motors were designed by varying the width of stator vibrator and the thickness, the length and the position of piezoceramics.

• Journal of the Semiconductor & Display Technology
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• v.9 no.2
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• pp.97-102
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• 2010

Propagation modes of symmetric metal-insulator-metal SPP waveguides are analyzed. Main characteristics of these waveguides such as mode effective index, propagation length, and penetration depths are calculated at the telecom wavelength for different layer thickness. We adopt Au, Al as a metal material and air, glass as a dielectric material and obtain different optical characteristics. The surface plasmon characteristics in this paper provide a numerical insight for designing nanostructure metal plasmon waveguide.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.225-233
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• 2002

The flexural vibration characteristics of a sandwich beam system with a partially inserted viscoelastic layer have been quantitatively studied using a finite element analysis in combination with a sine-sweep test. Antisymmetric mode shapes of the flexural vibration were visualized by the holographic interferometry and agreed with those calculated by the finite element simulation. Effects of the beam thickness as well as the length and thickness of partial viscoelastic layers on the system loss factor(η$\_$s/) and resonant frequency($\omega$$\_$r/) were significantly large fur the symmetric and antisymmetric modes of the beam system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.128-133
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• 2002

The main obstacle to high track density in HDD is the structural resonances of the suspension. The most critical mode is sway mode and second torsion mode, when a data is read and written. It is common fact that the effect of two modes is smaller when a thickness is bulky. But the stiffness of suspension is smaller, the slider can follow a disk better. Because these two fact are reciprocal, a compromise is needed. So we investigated another method to improve band width without changing of the thickness of suspension but with changing of the shape. In this paper, we use two method - Sensitivity analysis and SIP using ADS. And we obtained the optimized value close to target value.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.2
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• pp.47-54
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• 2012

In this study, composite laminate cantilever type cylindrical shells with edge-stiffeners are analyzed. A versatile 4-node flat shell element which is useful for the analysis of shell structures is used. An improved flat shell element is established by the combined use of the addition of non-conforming displacement modes and the substitute shear strain fields. Two models by load conditions are considered. Load type A and B are loaded by point load at the free edge and line load respectively. A various parameter examples are presented to obtain proper stiffened length and stiffened thickness of edge-stiffeners. It is shown that the thickness of shell can be reduced minimum 30% by appropriate edge-stiffeners.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.9
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• pp.782-787
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• 2008

First, the effect of the geometry such as the curved shape of the struts composing the truss structure of WBK is elaborated. Then, analytic solutions for the material properties of WBK and the maximum loads of a WBK-cored sandwich panel under bending are derived. A design optimization with the face sheet thickness and the core height selected as the design variables is presented for given slenderness ratios of the WBK core. Unless the face sheet thickness is limited, the optimal design to give the maximum load per weight is always found at a confluence of three failure modes, namely, face sheet yielding, indentation plastic, and core shear modeB plastic.