• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1216-1221
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• 2000

Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, 'rotary inertia' and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.9-12
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• 2000

The importance of the role of plastic spin in the rate-dependent response of materials at large deformations is the main objective of this work. After a brief presentation of a general consitutive framework for visco-rigid plasticity at large strains an isotropic/kinematic hardening and a visco-rigid plastic model are used to analyze the stress-strain response under simple shear. A clear understanding of the role of plastic spin is achieved by obtaining numerical analyzed results for different stress values in which the plastic spin consititutive parameters interrelaste with the strain rate and other more conventional model constants, Especially this paper is concerned with introducing behaviors of Al7075

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.625-628
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• 2000

Recently, composite structural systems have been developed actively due to its structural advantages of combining different materials. The objective of this paper is to investigate the structural behavior of composite connection which consist of steel beams and reinforced concrete columns (RCS). Five 2/3 scale joint specimens with variables mainly consist of shear resisting details, were tested under reversal loads. The results showed that RCS beam-column joints maintain ductility, strength compared to other RCS joints and exhibited excellent energy dissipating capacity when subjected to inelastic deformations under reversal load.

• Journal of the Korea Concrete Institute
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• v.12 no.4
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• pp.79-89
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• 2000

In this paper, the seismic analysis and the modeling techniques have been introduced for aseismic performances assessment, when seismic isolation bearings are applied on a real bridge. Nonlinear time-history analysis is carried out using finite element analysis program. In this study, EI Centro earthquake(1940, N00W), Mexico earthquake(1985, N90W), and earthquake simulation from modified SIMQKE are used as earthquake ground excitations. The seismic response of seismically isolated bridge is compared with that of a bridge using conventional Pot Bearings, after obtaining the displacements of the deck, the deformations of the piers, shear forces and moments of the bottoms of the piers. The analytical analysis results show that seismic isolation bearing, especially seismic isolation bearings with sliding mechanism, could reduce earthquake forces.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.28-32
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• 2003

Thermo-mechanical behavior of a ceramic ball grid array(CBGA) package assembly and wire bond ball grid array(WB-PBGA) package assemblies are characterized by high sensitive moire interferometry. Moire fringe patterns are recorded and analyzed at various temperatures in a temperature cycle. Thermal-history dependent analyses of global and local deformations are presented, and bending deformation(warpage) of the package and shear strain in the rightmost solder ball are discussed. A significant non-linear global behavior is documented due to stress relaxation at high temperature. The locations of the critical solder ball in WB-PBGA package assemblies are documented.

• Steel and Composite Structures
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• v.22 no.1
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• pp.183-201
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• 2016

Perforated steel beams can be optimised by increased beam depth and the moment of inertia combined with a reduced web thickness, favouring the use of original I-section beams. The designers are often confronted with situations where optimisation cannot be carried out effectively, taking account of the buckling risk at web posts, moment-shear transfers and local plastic deformations on the transverse holes of the openings. The purpose of this study is to suggest solutions for reducing these failure risks of tested optimal designed beams under applying loads in a self-reacting frame. The design method for the beams is the hunting search optimisation technique, and the design constraints are implemented from BS 5950 provisions. Therefore, I have aimed to explore the strengthening effects of reinforced openings with ring stiffeners, welded vertical simple plates on the web posts and horizontal plates around the openings on the ultimate load carrying capacities of optimally designed perforated steel beams. Test results have shown that compared to lateral stiffeners, ring and vertical stiffeners significantly increase the loadcarrying capacity of perforated steel beams.

• Advances in Computational Design
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• v.5 no.2
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• pp.177-193
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• 2020

In the present research, dynamic analysis of functionally graded (FG) graphene-reinforced beams under thermal loading has been carried out based on finite element approach. The presented formulation is based on a higher order refined beam element accounting for shear deformations. The graphene-reinforced beam is exposed to transverse periodic mechanical loading. Graphene platelets have three types of dispersion within the structure including uniform-type, linear-type and nonlinear-type. Convergences and validation studies of derived results from finite element approach are also presented. This research shows that the resonance behavior of a nanocomposite beam can be controlled by the GPL content and dispersions. Therefore, it is showed that the dynamical deflections are notably influenced by GPL weight fractions, types of GPL distributions, temperature changes, elastic foundation and harmonic load excitation frequency.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.61-64
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• 2003

The finite element method based on the refined beam theory is applied to the vibration problem of rotation composite box beams. The present beam model includes a number of non-classical structural effects such as transverse shear, warping deformations, geometric non-linearities. The nonlinear finite element equations of motion are obtained from Hamilton's principle. Vibration characteristics versus various parameters such as ply angle, collective pitch angle, pretwist and precone are investigated for rotation box ben and relevant conclusions are outlined.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.402-407
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• 2008

We suggest a linear elastic flat shell element based on the HT(hybrid Trefftz) method. We formulate the membrane part of the proposed element as an HT plane element with the drilling DOF. For the bending part, we developed a thick HT plate element that can represent transverse shear deformations accurately. Because we derive both the membrane and the bending parts consistently using the HT functional, we can easily construct the triangular and the quadrilateral elements in a unified way. In addition, warping of quadrilateral element is compensated by force and moment equilibrium equations. We evaluate the performance of the new element in terms of accuracy and convergence.

• Composites Research
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• v.30 no.6
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• pp.343-349
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• 2017

A multifield variational formulation is developed for the finite element (FE) cross-sectional analysis of composite beams. The cross-sectional warping displacements and sectional stresses are considered to be the primary variables through the application of Reissner's partially mixed principle. The warping displacements are modeled using generic FE shape functions with nonlinear distribution over the beam section. A generalized Timoshenko level stiffness matrix is derived which incorporates the effects of elastic couplings, transverse shear, and Poisson's deformations. The accuracy of the present analysis is validated for the stiffness constants and elastostatic responses of composite box beams which correlate well with the experimental data and other state-of-the-art approaches.