• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.886-889
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• 2002

Finite Element Method for 3-D static loaded passenger car tire on the rigid surface is performed for studying the stiffness of tire to compare with experimental data. The tire elements used for FEM are defined each component to allow an easy change for the design parameters. Also, a hyperelastic material which is composed of tread and sidewall has been used to consider a large deformation of rubber components. The orthotropic characters of rubber-cord composite materials are used as well. The air pressure, a vertical and a lateral load are applied step by step and iterated by Modified Newton method for geometric and boundary condition nonlinear simulation. This study shows nonlinear analysis method for tire and the bearing capacity of tire due to the external force.

• Wind and Structures
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• v.23 no.6
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• pp.485-503
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• 2016

To investigate the nonlinear aerostatic stability of the Hutong cable-stayed rail-cum-road bridge with ultra-kilometer main span, a FEM bridge model is established. The tri-component wind loads and geometric nonlinearity are taken into consideration and discussed for the influence of nonlinear parameters and factors on bridge resistant capacity of aerostatic instability. The results show that the effect of initial wind attack-angle is significant for the aerostatic stability analysis of the bridge. The geometric nonlinearities of the bridge are of considerable importance in the analysis, especially the effect of cable sag. The instable mechanism of the Hutong Bridge with a steel truss girder is the spatial combination of vertical bending and torsion with large lateral bending displacement. The design wind velocity is much lower than the static instability wind velocity, and the structural aerostatic resistance capacity can meet the requirement.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2723-2725
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• 2005

In this paper, a robust $H{\infty}$ stabilization problem to a uncertain discrete-time nonlinear systems with time-delay via fuzzy static output feedback is investigated. The Takagi-Sugeno (T-S) fuzzy model is employed to represent an uncertain nonlinear systems with time-delayed state. Then parallel distributed compensation technique is used for designing of the robust fuzzy controller. Using a single Lyapunov function, the globally asymptotic stability and disturbance attenuation of the closed-loop fuzzy control system are discussed. Sufficient conditions for the existence of robust $H{\infty}$ controllers are given in terms of linear matrix inequalities via similarity transform and congruence transform technique.

• Structural Engineering and Mechanics
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• v.9 no.2
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• pp.111-126
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• 2000

Truss type structures are attractive to a variety of engineering applications on earth as well as in space due to their high stiffness to mass ratios and ease of construction and fabrication. During the service life, an individual member of a truss structure may lose load carrying capacity due to many reasons, which may lead to collapse of the structure. An analytical and computational procedure has been developed to study the response of truss structures subject to member failure under static and dynamic loadings. Emphasis is given to the dynamic effects of member failure and the propagation of local damage to other parts of the structure. The methodology developed is based on nonlinear finite element analysis technique and considers elasto-plastic material nonlinearity, postbuckling of members, and large deformation geometric nonlinearity. The pseudo force approach is used to represent the member failure. Results obtained for a planar nine-bay indeterminate truss undergoing sequential member failure show that failure of one member can initiate failure of several members in the structure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.971-976
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• 2006

This paper presents a design technique of steel structures subjected to static and dynamic loadings using practical nonlinear inelastic analysis software. The beam-column approach using the stability functions and the plastic hinge concept enables the software to suitably predict second-order effects and inelastic behavior of beam-columns. For dynamic analysis. the incremental from of the equation of motion is solved by the use of a step-by-step numerical integration procedure in which the assumption of constant acceleration over a small time step is employed. The accuracy of the analysis program is validated using the results of ABAQUS program and experimental tests. A user-friendly graphic interface of the software is developed to facilitate the modeling process and result interpretation of the problem. A design example of large span bridge is presented to detail the direct design process using the practical advanced analysis software.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.2
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• pp.33-47
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• 2001

성능에 기초한 내진설계에서는 구조물이 보유하고 있는 능력을 효과적으로 파악하기 위해서 비선형 정적 해석이 적용되고 있다. 그러나 비선형 정적해석은 고차모드에 대한 효과를 고려하지 못함으로써 고층구조물이나 비정형 구조물과 같은 경우에는 정확한 비선형 지진응답의 산정과 내진성능을 평가하는데 문제점을 가지고 있다. 본 연구에서는 건축구조물의 선형 및 비선형 지진응답 평가를 위하여 응답 스펙트럼해석을 통하여 얻어지는 층전단력으로부터 층하중을 산정하는 유사동적해석법이 적용되었다. 제안된 방법을 비선형 정적 해석에 적용하여 구조물의 비선형 자동응답을 비선형 시간이력해석의 결과와 비교하였다. 기존의 층분포하중에 의한 비선형 지진응답과 비교하였으며, 제안된 방법에 의한 지진 응답이 구조물의 비선형 거동특성을 가장 정확하게 표현하였다. 그러므로 본 연구에서 제안된 방법을 사용하여 비선형 정적 해석을 수행한다면 비교적 명확한 건축물의 비선형 거동특성과 내진성능을 평가할 수 있을 것으로 판단된다.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.119-126
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• 2006

Capacity spectrum method(CSM) of ATC-40(1996) and displacement coefficient method(DCM)of FEMA-273(1997) are applied to evaluate the seismic performance of bridges. In this study, equivalent response is obtained from nonlinear static analysis for the 3spans continues bridge and nonlinear maximum displacement response is calculated using CSM and DCM. Nonlinear maximum displacement response of DCM is larger than this of CSM. It is method that DCM can evaluate target displacement and ductility of structural to be easy and simple, but tend to overestimate the maximum displacement response. Therefore, this method is mainly used at preparation design level to evaluate the structural response. It is not desirable to evaluate the seismic performance using DCM.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.9
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• pp.2833-2842
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• 1996

This paper is to practice optimal rigidity design by the strain energy density estimation method for static buckling and sizing design sensitivity analysis for dynamic buckling of a nonlinear vehicle frame structure from those results. Using these sizing design sensitivity resutls, an optimization of a nonlinear vehicle frame structure with dynamic buckling constraint is carrried out with the graient projection method.

• Coupled systems mechanics
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• v.4 no.3
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• pp.251-262
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• 2015

The current paper aims at investigating the nonlinear dynamical behaviour of an electrically actuated microcantilever. The microcantilever is excited by a combination of AC and DC voltages. The nonlinear equation of motion of the microcantilever is obtained by means of force and moment balances. A high-dimensional Galerkin scheme is then applied to reduce the equation of motion to a discrete model. A numerical technique, based on the pseudo-arclength continuation method, is used to solve the discretized model. The electrostatic deflection of the microcantilever and static pull-in instabilities, due to the DC voltage, are analyzed by plotting the so-called DC voltage-deflection curves. At the simultaneous presence of the DC and AC voltages, the nonlinear dynamical behaviour of the microcantilever is analyzed by plotting frequency-response and force-response curves.

• Structural Engineering and Mechanics
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• v.42 no.5
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• pp.645-675
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• 2012

An effective design technique for symmetrical coupled shear walls is presented. Proposed formulation including assumptions and steps with mathematical formulation has been elaborated to make the design technique. An example has been considered to validate the technique with the DRAIN-3DX (1993) and SAP V 10.0.5 (2000) nonlinear programs. Parametric study has also been considered to find out the limitations along with remedial action of this technique. On the other hand, nonlinear static analysis is considered to determine the response reduction factor of coupled shear walls. Finally, it has been concluded in this paper that the proposed design technique can be considered to design the coupled shear walls under seismic motion.