• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.648-654
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• 2007

This paper presents the result of a comparison study to evaluate the performance of several semi-active control algorithms for use with large-scale MR damper applied to a building structure under seismic excitation using real-time hybrid test method. Recently, a variety of semi-active control algorithm studies are developed and generally evaluated the performance by using numerical analysis. In this paper real-time hybrid test method was applied to performance evaluating of semi-active control algorithms including a clipped optimal algorithm and the modulated homogeneous friction algorithm.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.590-595
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• 1998

This study was performed to obtain a numerical model for a viscous fluid damper from an experimental testing. The input signals for displacement were chosen as two type : a triangular and a sinusoidal forms. The performing test parameters were the area of the resistant plate and the oil film thickness of the viscous fluid and the temperature effect was neglected. The numerical model was established by assuming to behavior as an non-Newtonian fluid. The test results were summarized by the equation of F = 0.0308A(V/d)$^{0.51}$25/. Using the obtainal formula, the procedure to apply the viscous damper for a real structure design was introduced..

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.34-40
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• 2004

In this paper, peliminary design procedure of magnetorheological (MR) dampers is developed for controlling the building response induced by seismic excitation. Hysteretic biviscous model which is simple and can describe the hysteretic characteristics of MR damper is used for parametric studies. The capacity of MR damper is determined as a portion of not the building weight but the lateral restoring force. A method is proposed for the optimal placement and number of MR dampers, and its effectiveness is verified by comparing it with the simplified search algorithm. Numerical results indicate that the capacity, number and the placement can be reasonably determined using the proposed design procedure.

• Earthquakes and Structures
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• 제3권6호
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• pp.805-820
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• 2012

An enhanced and efficient methodology is proposed for evaluating the robustness of an uncertain structure with passive dampers. Although the structural performance for seismic loads is an important design criterion in earthquake-prone countries, the structural parameters such as storey stiffnesses and damping coefficients of passive dampers are uncertain due to various factors or sources, e.g. initial manufacturing errors, material deterioration, temperature dependence. The concept of robust building design under such uncertain structural-parameter environment may be one of the most challenging issues to be tackled recently. By applying the proposed method of interval analysis and robustness evaluation for predicting the response variability accurately, the robustness of a passively controlled structure can be evaluated efficiently in terms of the so-called robustness function. An application is presented of the robustness function to the design and evaluation of passive damper systems.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.349-356
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• 2002

Anticipating potential strong earthquakes, bracing dampers for better seismic performance are being developed in Korea, while similar ones are already developed in other countries. But, there are lack of relevant research on Slender Brace Dampers rather than hysteretic dampers, whose concept is also inappropriate for rehabilitation existed slender braced frame. For the development of Slender Brace Damper in slender braced frame, this research investigates Slender Brace Damper possessing various shapes of hyteretic damper through performing experimental test under cyclic loadings. As a result at this paper, Energy dissipation of test specimens (H35B20PS, H35B20TS, H20B60PS) are superior.

• Structural Engineering and Mechanics
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• 제59권5호
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• pp.821-840
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• 2016

A simple design process is proposed for supplemental viscous dampers based on structural safety redundancy. In this process, the safety redundancy of the primary structure without a damper is assessed by the capacity and response spectra. The required damping ratio that should be provided by the supplemental dampers is estimated by taking the structural safety redundancy as a design target. The arrangement of dampers is determined according to the drift distribution obtained by performing pushover analysis. A benchmark model is used to illustrate and verify the validity of this design process. The results show that the structural safety redundancy of the structure provided by the viscous dampers increases to approximately twice that of the structure without a damper and is close to the design target. Compared with the existing design methods, the proposed process can estimate the elastic-plastic response of a structure more easily by using static calculation, and determine the required damping ratio more directly without iterative calculation or graphical process. It can be concluded that the proposed process is simple and effective.

• Steel and Composite Structures
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• 제18권2호
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• pp.481-496
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• 2015

A Lead Extrusion Damper (LED) is experimentally studied under various frequencies and displacement amplitudes. Experimental results show that the force-displacement hysteresis loops of the LED are close to rectangular and the force-velocity hysteresis loops exhibit nonlinear hysteretic characteristic. Also, the LED can provide consistent energy dissipation without any stiffness degradation. Based on the experimental results, a mathematical model is then proposed to describe the effects of frequency and displacement on property of LED. It can be proved from the comparison between experimental and numerical results that the mathematical model can accurately describe the mechanical behavior of LED. Subsequently, the seismic responses of the Schwedler reticulated shell structure with LEDs are analyzed by ANSYS software, in which three different installation forms of LEDs are considered. It can be concluded that the LED can effectively reduce the displacement and acceleration responses of this type of structures.

• Smart Structures and Systems
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• 제29권4호
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• pp.549-560
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• 2022

The optimum damping and tuning frequency ratio of the tuned mass damper-inerter (TMDI) for the base-isolated structure is obtained using the numerical searching technique under stationary white-noise and filtered white-noise earthquake excitation. The minimization of the isolated structure's mean-square relative displacement and absolute acceleration, as well as the maximization of the energy dissipation index, were chosen as the criteria for optimality. Using a curve-fitting technique, explicit formulae for TMDI damping and tuning frequency for white-noise excitation are then derived. The proposed empirical expressions for TMDI parameters are found to have a negligible error, making them useful for the effective design of base-isolated structures. The effectiveness of TMDI and its optimum parameters are influenced by the soil condition and isolation frequency, according to the comparison made of the optimized parameters and response with different soil profiles. The effectiveness of an optimally designed TMDI in controlling the displacement and acceleration response of the flexible isolated structure under real and pulse-type earthquakes is also observed and found to be increased as the inertance mass ratio increases.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 봄 학술발표회 논문집
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• pp.99-106
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• 1995

The seismic responses of a base Isolated Pressurized Water Reactor(PWR) are investigated using a mathematical model which expresses the superstructure as a linear lumped mass-spring and the seismic Isolator as an equivalent spring-damper. Time history analyses are performed for the 1940 El Centre earthquake with linear amplification. In the analysis 5% of structural damping is used for the superstructure. The effects of high damping rubber bearing on seismic response of the superstructure in base isolated system are evaluated for four stiffness model types. The acceleration responses in base isolated PWR superstructure with high damping rubber bearings are much smaller than those in fixed base structure. In the higher strain region where stiffness behaves non-linearly, the acceleration responses modelled by one equivalent stiffness are smaller than those in nonlinear spring model, and the higher stiffness spring model of isolator exhibits larger peak acceleration response at superstructure in the frequency range above 2.0 Hz. when subjected to linearly amplified 1940 El Centre earthquake.

• Steel and Composite Structures
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• 제29권3호
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• pp.287-299
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• 2018

The purpose of this study is to investigate the effectiveness of damped cable systems (DCS) to mitigate the earthquake-induced responses of a building frame structure. The seismic performance of the DCS is investigated using the fragility analysis and life cycle cost evaluation of an existing building retrofitted with the DCS, and the results are compared with the structure retrofitted with conventional fluid viscous dampers. The comparison of the analysis results reveals that, due to the self-centering capability of the DCS, residual displacement approximately reaches to zero for the structure retrofitted with the DCS. The fragility analysis shows that the structure retrofitted with the DCS has the least probability of reaching the specific limit states compared to the bare structure and the structure with the conventional fluid viscous damper (VD), especially under the severe ground motions. It is also observed that both the initial and the life cycle costs of the DCS seismic retrofitting technique is lesser compare to the structure retrofitted with the VD.