• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.169-175
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• 1997

Recently it is increased by degrees to produce complex and large lattice structures such as bridge, tower, crane, and space structures. In general, in order to analyse these structures we have used finite element method(FEM). In this method, however, it is necessary to use a large amount of computer memory and to take long computation time. For overcoming this problem, the Authors have developed the transfer dynamic stiffness coefficient method(TDSCM) which consists on the concept of the substructure synthesis method and transfer influence coefficient method. In this paper, the new free vibration analysis method for large type lattice structure is formulated by the TDSCM. And the results obtained by TDSCM are compared with those obtained by FEM, transfer matrix method and experiment. And it is confirmed for TDSCM to be the numerical high accuracy and high speed structure analysis method.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.64-71
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• 2009

The development of more safe recliners is an important issue in the automotive industry. However, the development of new recliners is costly and take much time because it is typically based on experimental evaluation using prototypes. This study presents the evaluation of rear crashworthiness for round recliner using finite element method. That reduces the number of repeating test and gives an information about stiffness. To evaluate rear crashworthiness, the FMVSS 301 simulation and pendulum impact simulation were performed. The load path on two simulations was observed and compared each other in this paper. Also stress, strain and internal energy was compared. It is attempted the tooth strength simulation using a substructure option on PAM-CRASH.

• 한국지진공학회논문집
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• 제18권4호
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• pp.193-200
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• 2014

This paper examines the pounding problem between adjacent decks subjected to strong earthquakes. The elastomeric bearings in an isolated bridge reduce the stresses on the superstructure and cushion the impact by transferring smaller seismic forces to the substructure. On the other hand, these bearings also allow large horizontal displacement of the superstructure due to seismic forces. Bridges having various supporting soil conditions and different frequency ratios between adjacent decks are investigated by numerical analysis. In the analysis, decision making is conducted whether the collision took place or not and, the magnitude of pounding force and the duration time of collision are obtained and the results are discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.666-669
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• 2004

Substructures position is considered as design parameter to obtain optimal structural changes to raise its dynamic characteristics. In conventional SDM (structural dynamics modification) method, the layout of modifying substructures position is first fixed and at that condition the structural optimization is performed by using the substructures size and/or material property as design parameters. But in this paper as a design variable substructures global translational and rotational position is treated. For effective structural modification the eigenvalue sensitivity with respect to that design parameter is derived based on measured frequency response function. The optimal structural modification is calculated by combining eigenvalue sensitivities and eigenvalue reanalysis technique iteratively. Numerical examples are presented to the case of beam stiffener optimization to raise the natural frequency of plate.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.101-109
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• 1997

An analytical procedure on the base of the substructure synthesis and assumed modes method is developed to investigate the flexibility effect of bladed disk assembly on vibrational modes of flexible rotor system. In modeling the system, Coriolis forces, gyroscopic moments, and centrifugal stiffening effects are taken into account. The coupled vibrations between the shaft and bladed disk are then extensively investigated through the numerical simulation of simplified models, with varying the shaft rotational speed and the pretwist and stagger angles of the blade. It is found that the Coriolis and inertia forces and the inertia torque, which are induced by the one nodal diameter modes of the bladed disk and vary depending upon the stagger and pretwist angles, lead to the coupled motions of the shaft and the bladed disk.

• Structural Engineering and Mechanics
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• 제70권4호
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• pp.421-429
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• 2019

This paper presents an analytical model for the estimation of initial lateral stiffness of steel moment resisting frames with masonry infills. However, rather than focusing on the single bay-single storey substructure, the developed model attempts to estimate the global stiffness of multi-storey and multi-bay frames, using an assembly of equivalent springs and taking into account the shape of the lateral loading pattern. The contribution from each infilled frame panel is included as an individual spring, whose properties are determined on the basis of established diagonal strut macro-modeling approaches from the literature. The proposed model is evaluated parametrically against numerical results from frame analyses, with varying number of frame stories, infill openings, masonry thickness and modulus of elasticity. The performance of the model is evaluated and found quite satisfactory.

• 한국BIM학회 논문집
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• 제10권4호
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• pp.40-49
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• 2020

This report describes the development of a program that can be linked to an alignment and extracts related information using a prefab structured digital engineering model. The subject bridge was set as a straight alignment, the Superstructure type as Precast girder and the Substructure type as Precast pier and Cast-in-situ Abutment. We identified the variables required to create a digital engineering model and reviewed them to create the digital engineering model by entering them as numerical values in the program. In addition, it is configured so that the variables linked to the alignment can be entered numerically. The quantity takeoff can be calculated when the design is complete. The purpose of the program development presented in this report is to enable the designers to select the optimal alternative by designing a bridge that best fits their current situation, extracting the relevant information and then by providing it to the manufacturer and construction company.

• 터널과지하공간
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• 제12권2호
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• pp.120-129
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• 2002

중부지역에 존재하는 대규모 석회암층을 통과하는 고속도로가 신설되는 가운데, 일부 교량의 교대 하부 얕은 심도에서 자연 생성된 석회암 공동이 다수 발견됨에 따라. 교대 및 교량의 안정성 확보를 위한 추가 정밀조사가 실시되었다. 정밀구조지질조사를 통해 고속도로 노선을 따른 지질도가 작성되었으며 이를 토대로 전기비저항 탐사가 일부 구간에 대해 실시되었다. 이 결과 석회암 공동의 존재가 의심되는 부분에 대해 국부적 인 탄성파탐사가 수행됨으로써 석회암 공동의 위치 및 규모가 최종 파악되었으며, 일련의 현장조사 및 실험실 시험결과를 이용한 수치해석이 이루어졌다. 수치해석에 의한 교대 및 교량의 안정성 분석 결과, 시멘트 그라우팅에 의한 교량하부 기초의 보강이 제안되었다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.527-534
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• 2006

A real-time hybrid method, in which the experimental implementation and the numerical computation of a structure are simultaneously carried out in real-time and combined on-line, has been used as a dynamic testing technique of structure to investigate its dynamic behaviors. In this paper, an experimental hybrid method, which implements the earthquake response control of a building structure with a TLD by using only a TLD as an experimental part, is proposed and is experimentally verified through a shaking table test. In the proposed methodology, the whole building structure with a TLD is divided into the upper TLD and the lower structural parts as experimental and numerical substructures, respectively. At the moment, the control force acting between their interface is measured from the experimental TLD with shear-type load-cell which is mounted on shaking table. Shaking table vibrates the upper experimental TLD with the response calculated from the numerical substructure, which is subjected to the excitations of the measured interface control force at its top story and an earthquake input at its base. The experimental results show that the conventional method, in which both a TLD and a building model are physically manufactured and are tested, can be replaced by the proposed methodology with a simple experimental installation and a good accuracy for evaluating the control performance of a TLD.

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1229-1238
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• 2002

In this paper, a method to obtain the sensitivity of eigenvalues and the random responses of the structure with uncertain parameters is proposed. The concept of the proposed method is that the perturbed equation of each uncertain substructure is obtained using the finite element method, and the perturbed equation of the overall structure is obtained using the mode synthesis method. By this way, the reduced order perturbed equation of the uncertain system can be obtained. And the response of the uncertain system is obtained using probability method. As a numerical example, a simple piping system is considered as an example structure. The damping and spring constants of the support are considered as the uncertain parameters. Then the variations of the eigenvalues, the correlation function and the power spectral density function of the responses are calculated. As a result, the proposed method is considered to be useful technique to analyze the sensitivities of eigenvalues and random response against random excitation in terms of the accuracy and the calculation time.