• Proceedings of the KOSOMBE Conference
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• v.1994 no.05
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• pp.131-135
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• 1994

In order to study the shape and dimensions of heart, the procedures to reconstruct a three dimensional left ventricular geometry from two dimensional echocardiographic images is studied including the coordinate transformation, curve fitting and interpolation utilizing three dimensional position registration arm. Nonlinear material property of the left ventricular myocardium was obtained by finite element method performed on the reconstructed geometry and optimization techniques which compare the computer predicted 3D deformation with the experimentally determined deformation. Afterwards using the obtained nonlinear material propertry the stress distribution related with oxyzen consumption rate was analyzed.

• Structural Engineering and Mechanics
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• v.1 no.1
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• pp.17-30
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• 1993

A practical multi-spring model is proposed for a nonlinear analysis of reinforced concrete members, especially columns, taking into account the interaction of axial load and bi-directional bending moment. The parameters of the model are determined on the basis of material properties and section geometry. The axial force-moment interaction curve of reinforced concrete sections predicted by the model was shown to agree well with those obtained by the flexural analysis utilizing realistic stress-strain relations of materials. The reliability of the model was also examined with respect to the test of reinforced concrete columns subjected to varying axial load and bi-directional lateral load reversals. The analytical results agreed well with the experiment.

• Structural Engineering and Mechanics
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• v.49 no.4
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• pp.463-477
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• 2014

In this paper, seismic performance of Kozyatagi Bridge is evaluated by employing nonlinear elasto-plastic dynamic analysis and the deformation-based performance. The time-history records of the 1999 Izmit, 1971 San Fernando and 1989 Loma Prieta earthquakes are modified by adopting a probability of exceedance of 2% in 50 years corresponding to the return period of 2475 years. The analysis is carried out for three different bearing cases which are movable bearings, restrained bearings, and movable bearings with viscous fluid dampers in the radial direction. The analysis results show that the bridge can be retrofitted with viscous fluid dampers. In this case the reinforced concrete piers need not be strengthened by any jacketing techniques in order to preserve the original architectural appearance of the bridge. The retrofitting design of the bridge with viscous fluid dampers is also presented in detail.

• Earthquakes and Structures
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• v.15 no.3
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• pp.285-294
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• 2018

In this study, nonlinear dynamic response of a concrete plate retrofit with Aluminium oxide ($Al_2O_3$) under seismic load and magnetic field is investigated. The plate is a composite reinforced by Aluminium oxide with characteristics of the equivalent composite being determined using Mori-Tanka model considering agglomeration effect. The plate is simulated with higher order shear deformation plate model. Employing nonlinear strains-displacements, stress-strain, the energy equations of column was obtained and using Hamilton's principal, the governing equations were derived. Differential quadrature method (DQM) in conjunction with Newark method is applied for obtaining the dynamic response of structure. The influences of magnetic field, volume percent of nanoparticles, geometrical parameters of column, agglomeration and boundary conditions on the dynamic response were investigated. Results showed that with increasing volume percent of nanoparticles, the dynamic deflection decreases.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.10-14
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• 2002

Structural behavior of high-pressure composite vessels of TYPE 3 (full-wrapped over a seamless aluminum liner) was studied through numerical simulations based on 3D nonlinear finite element method. Under high-pressure loading, a TYPE 3 composite vessel shows material nonlinearity due to elastic-plastic deformation of aluminum liner, and mismatch of deformation at the junction of cylinder and dome causes geometrical nonlinearity. Finite element modeling and analysis technique considering this nonlinearity was presented, and a pressure vessel of 6.8L of internal volume was analyzed. Design specification to satisfy requirements was determined based on analysis results.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.550-557
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• 2003

Hyperelastic constitutive equations for nonlinear deformation of the periodontal ligament were investigated. The parameters in the strain energy potentials were obtained from experimental data for uniaxial and shear responses of the human periodontal ligament. The hyperelastic constitutive equations based on two strain energy potentials was also compared with the linear elastic equation, which is recently reported. The best fitted parameters in the strain energy potentials was applied to finite element program (ABAQUS) to simulate special orthodontic treatment of a mandibular canine.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.330.1-330
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• 2002

Elastomer is extensively used to reduce of vibration machine or structure. Over the years an enormous effort has been put into developing procedures to provide properties of rubber material fur design function. However, there are still a lot of difficulties to analyze static characteristic of rubber components with hyper elasticity and nonlinear large deformation. In this paper material property is obtained by strain-stress curve using a tension test. (omitted)

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.4
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• pp.95-100
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• 1999

Dynamic measurements are used rather sparingly to determine the elastic modull of rock cores and modulus values are not much utilized in design practice. The reason seems to result from the general perception that values obtained by dynamic measurement are much higher (about 10 times) than those determined statically. This paper presents results from dynamic and static tests on rock cores. The findings are: 1) elastic modull can be consistently determined by laboratory seismic testing. 2) nonlinear deformation characteristics of rock cores was tentatively proposed with variation in elastic modulus with strain.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.236-243
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• 2005

Nonlinear static analysis is used to quantify the resistance of the structure to lateral deformation and to gauge the mode of deformation and intensity of local demands. A simple method for the nonlinear static analysis of complex building structures subjected to monotonically increasing horizontal loading(pushover analysis) is presented. The method is designed to be a part of new methodologies for the seismic design and evaluation of structures. A variety of existing pushover analysis procedures are currently being consolidated under programs such as ATC 40 and FEMA 273. And various techniques have been recommended, including the use of constant lateral force profiles and the use of adaptive and multimodal approaches. In this paper a modal pushover analysis using design response spectra of UBC 97 is proposed. Proposed method is compared against the method in FEMA 273 and ATC 40, and results of time history analysis.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.124-127
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• 2002

This paper presents a 3D shape optimization algorithm for electromagnetic devices using the design sensitivity analysis with finite element method. The structural deformation analysis based on the deformation theory of the elastic body under stress is used for mesh renewing. The design sensitivity and adjoint variable formulae are derived for the 3D nonlinear finite element method with edge element. The proposed algorithm is applied to the shape optimization of 3D electromagnet to get a uniform flux density at the air gap.