• Structural Engineering and Mechanics
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• v.7 no.1
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• pp.95-110
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• 1999

An effective moment of inertia is developed for a rectangular, prismatic elastoplastic beam with elastic, linear-hardening material behavior. The particular solution for a beam with elastic, perfectly plastic material behavior is also presented with applications for beam bending in closed-form. Equations are presented for the direct application of the virtual work method for elastoplastic beams with concentrated and distributed loads. Comparisons are made between the virtual work method deflections and the deflections obtained by using an average effective moment of inertia over two lengths of the beam in the elastoplastic region.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.53-60
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• 2003

This paper explores the governing differential equations for the non-linear behavior of shear deformable simple beam with a concentrated load. In order to apply the Bernoulli-Euler beam theory to simple beam, the bending moment equation on any point of the elastica is obtained by concentrated load. The Runge-Kutta and Regula-Felsi methods, respectively, are used to integrate the governing differential equations and to compute the beam's rotation at the left end of the beams. The characteristic values of deflection curves for various load parameters are calculated and discussed

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.258-265
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• 2002

Most structures are expected deform nonlinear and inelastic behavior when subjected to strong ground motion. Nonlinear time history analysis(NTHA) is the most rigorous procedure to compute seismic performance in the various inelastic analysis methods. But nonlinear analysis procedures necessitate more reliable and practical tools for predicting seismic behavior of structures. Some building codes propose the capacity spectrum method. This method is the concept of an equivalent linear system, wherein a linear system having reduced stiffness and increased damping is used to estimate the response of the nonlinear system. This procedure are conceptually simple, but the iterative procedure is time-consuming and may sometimes lead to no solution or multiple solutions. This paper presents a nonlinear direct spectrum method(NDSM) to evaluate seismic performance of structures, without iterative computations, given by the structural initial elastic period and yield strength from the pushover analysis, especially for mixed building structure.

• 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.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.2
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• pp.117-127
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• 2000

In this paper, we propose a new convex combination weight rule for the cross decomposition method which is known to be one of the most reliable and promising strategies for the large scale optimization problems. It is called generalized cross decomposition, a modification of linear mean value cross decomposition for specially structured linear programming problems. This scheme puts more weights on the recent subproblem solutions other than the average. With this strategy, we are having more room for selecting convex combination weights depending on the problem structure and the convergence behavior, and then, we may choose a rule for either faster convergence for getting quick bounds or more accurate solution. Also, we can improve the slow end-tail behavior by using some combined rules. Also, we provide some computational test results that show the superiority of this strategy to the mean value cross decomposition in computational time and the quality of bounds.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.629-634
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• 2000

Dynamic behavior of an automatic dynamic balancer is analyzed by a theoretical approach. Using Lagrange's equation, we derive the non-linear equations of motion for an automatic dynamic balancer equipped in a rotor with the bending flexibility with respect to the rectangular coordinate. Considering the rotor bending flexibility we analyze out-of-plane vibrations as well as in-plane vibrations of the automatic dynamic balaner. The time responses are computed from the non-linear equations by using a time integration method. We also investigate the effect of rotor flexibility on the behavior of the automatic dynamic balancer

• Nuclear Engineering and Technology
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• v.30 no.5
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• pp.387-395
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• 1998

In general, the laminated rubber bearing (LRB), a composite structure laminated with the elastic rubber and steel plates, has a complex hysteretic nonlinear characteristics in relationships between the restoring force and shear deflection. The representative nonlinear characteristics of LRB include the change of hysteresis loop with cyclic shear deflections and the hardening effects at large shear deflection regions. Changes of the hysteresis loop of LRB with cyclic shear deflections affect the horizontal stiffness and the damping characteristics. The hardening behavior of LRB in large shear deflection region results in an increased horizontal stiffness and therefore, has a great impacton the seismic responses. In this paper, the seismic response analysis is carried out using the modified hysteretic bi-linear model of LRB, which takes into account the hysteresis loop change and the hardening behavior with cyclic shear deflection. The results on seismic responses are compared with those obtained using the widely used hysteretic hi-linear model. The new model is found to reveal the greater amount of peak acceleration response.

• Computational Structural Engineering
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• v.7 no.2
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• pp.61-67
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• 1994

The objective of this numerical analysis is to trace the hysteretic behavior of steel angles under very-low-cycle loading test, especially the history and cumulative state of local stress-strain at their critical parts. The computer model is based on a three-dimensional, non-linear analysis by using the finite element program, MSC/NASTRAN, which includes the effects of the material and geometric non-linearities. The analysis was performed as two stage procedures, namely Analysis I and II. The overall behavior from this analysis showed good agreement with the experiment.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.988-992
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• 2008

A poly(methyl red) film-modified glassy carbon electrode (PMRE) was fabricated for determination of norfloxacin (NFX). The electrochemical behavior of NFX was investigated and a well-defined oxidation peak with high sensitivity was observed at the film electrode. PMRE greatly enhanced the oxidation peak current of NFX owing to the extraordinary properties of poly(methyl red) film. Based on this, a sensitive and simple voltammetric method was developed for measurement of NFX. A sensitive linear voltammetric response for NFX was obtained in the concentration range of $1\;{\times}\;10^{-6}\;-\;1\;{\times}\;10^{-4}$ mol/L and the detection limit was $1\;{\times}\;10^{-7}$ mol/L using linear sweep voltammetry (LSV). The proposed method possessed advantages such as low detection limit, fast response, low cost and simplicity. The practical application of this new analytical method was demonstrated with NFX pharmaceuticals.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.146-153
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• 2001

In this paper, the governing differential equations for the non-linear behavior of shear deformable variable-arc-length beams subjected to an end moment are derived. The beam model is based on the Bernoulli-Euler beam theory. The Runge-Kutta and Regula-Falsi methods, respectively, are used to integrate the governing differential equations and to compute the beam's rotation at the left end of the beams. Numerical results are compared with existing closed-form and numerical solutions by other methods for cases in which they are available. The characteristic values of deflection curves for various load parameters are calculated and discussed.