• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.3
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• pp.21-28
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• 2008

To evaluate the seismic performance of multi-degree of freedom(MDF) systems, repeated nonlinear response history analyses are often conducted, which require extensive computational efforts. To reduce the amount of computation required, equivalent single degree of freedom(SDF) systems representing complex multi-degree of freedom(MDF) systems have been developed. For the equivalent SDF systems, bilinear models and trilinear models have been most commonly used. In these models, the P-$\Delta$ effect due to gravity loads during earthquakes can be accounted for by assigning negative stiffness after elastic range. This study evaluates the adequacy of equivalent SDF systems having these hysteretic models to predict the actual response of steel moment resisting frames(SMRF). For this purpose, this study conducts cyclic pushover analysis, nonlinear time history analysis and incremental dynamic analysis(IDA) for SAC-Los Angeles 9-story buildings using nonlinear MDF models(exact) and equivalent SDF models(approximate). In addition, this study considers the strength limited model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.4
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• pp.175-184
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• 2006

Two methods of the nonlinear static pushover analysis have been presented for the performance-based seismic design and evaluation of MDOF continuous bridges. Guidelines for buildings presented in FEMA-273 applying the Displacement Coefficient Method (DCM) and in ATC applying the Capacity Spectrum Method(CSM) have been modified for MDOF bridges. Two methods are compared with the time- history analysis. The lateral load distribution pattern for seismic loads has been examined in the static pushover analysis. The force-based fiber frame finite element has been implemented in the modeling of reinforced concrete piers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1089-1090
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.117-118
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• 2009

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.4
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• pp.377-386
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• 2003

The proposed simplified MDOF model is applied to a half-scale single-story reinforced masonry test building with a single diagonally-sheathed diaphragm. Comparisons of analytical studies to experimental tests can be valuable for understanding the seismic response of these types of buildings and for determining the qualities and limitations of the simplified models. A model calibration process is performed in this paper to determine the required structural properties based on the elastic and inelastic test responses for test building. This approach is necessary since established methods to determine the in-plane and out-of-plane stiffness, strength, and hysteresis do not exist.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.3
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• pp.271-280
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• 2003

The purpose of the study presented in this paper is to develope the general model for capture of the linear and nonlinear response of a flexible diaphragm building in which there are significant contributions from the out-of-plane walls. Two single-story single-diaphragm half scale reinforced masonry buildings were tested by researchers at the United States Army Construction Engineering Research Laboratory (CERL). The first had a metal deck diaphragm. The second specimen had a diaphragm with a single layer of diagonal lumber sheathing, A multiple degree of freedom (MDOF) approach is adopted in this paper. The required stiffnesses and strengths of the components within this model are determined.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.21-30
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• 2021

Architectural cultural properties suffer a lot of damage due to various environmental factors. In order to preserve damaged cultural properties, preventive preservation and long-term preservation management are becoming more important. Therefore, research on a scientific non-destructive testing method applicable to regular inspection is required. For related research, DangGan with a high flag-pole shape was selected as the subject of study among various cultural properties. Among the preserved DangGans, a basic study was conducted on the analysis technique to evaluate the structural stability by selecting Treasure No. 49 Naju SeokDangGan. An idealized model was presented and a multi-degree of freedom equation of motion was derived. In addition, an equation for estimating the critical stiffness value for each joint position is presented.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.125-129
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• 2009

본 연구에서는 동강성법을 이용하여 2자유도 진동시스템을 모델링하였다. 등가 모델을 구성한 후 Inertance의 크기에 따라 변화되는 시스템의 특성을 규명하였다. 2자유도 진동 시스템을 단일 모우드 소거에 적용할 경우 해석적인 설계 방법론을 1) 감쇠가 없는 경우 2) 1개의 감쇠기를 갖는 경우로 나누어 제시하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.10a
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• pp.205-209
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• 1994

본 연구에서는 오디오용 데크의 음질특성과 벨트구동계의 회전진동 특성과의 연관성을 규명하고자 한다. 이를 위해 벨트구동계를 다자유도 진동계로 모델링하여 회전진동 특성을 규명하고 실험으로 확인하였다. 이의 결과를 실제 데크에 응용하기 위해 각 파라미터의 변화에 따른 특성변화의 경향을 살펴보았으며, 당사에서 개발중인 신모델에서 회전비의 적절한 설계를 제안하여 우수한 음질특성을 확인하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.139-147
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• 2001

In this study a path control scheme of simulation models of various vehicles to evaluate their handling characteristic is developed. Based on the forward target method, path deviation error is estimated and the required steering effort to reduce the error is computed by Ziegler-Nichols PID control rule. Velocity control model is also included in the proposed path control scheme to achieve the desired velocity. The path control scheme is implemented on a full vehicle model to perform ISO test procedures, such as steady state cornering, lane change, and sinusoidal input, etc. Through the simulations of ISO test procedures and comparison with actual tests, effectiveness and validity of the path control model is demonstrated.