• 한국공간구조학회논문집
• /
• 제16권3호
• /
• pp.99-106
• /
• 2016

The proposed hybrid damper installs at a coupling beam and consists of a high-damping rubber (HDR) and steel pin. The proposed hybrid damper adopted a pin-lock system acts as a viscoelastic damper under wind load (small displacement) while it behaves as a hysteretic damper under earthquake load (large displacement). In this paper, the pin-lock mechanism and structural performance of the proposed hybrid damper is evaluated through experiment. Experiments were carried out with the variables which displacement, loading frequency and steel pin quantities were used. Test results showed that the pin-lock mechanism and the performance of the hybrid damper under a large displacement were verified. Also equivalent damping ratios of HDR were increasing at a small displacement as displacement amplitudes were increasing. However HDR did not depend on frequency.

• 대한건축학회논문집:구조계
• /
• 제34권1호
• /
• pp.33-39
• /
• 2018

This study performed experimental validation of the hysteretic steel slit damper's basic and dependent characteristics, which should be considered for the design. The basic characteristic of the steel slit damper is used for determining design properties of non-linear analysis, such as yielding strength, yielding displacement, elastic stiffness and post-yielding stiffness. In order to evaluate dependent characteristics of the hysteretic steel slit damper, repeated deformation capacity with respect to the displacement, velocity and aspect ratio of the damper was evaluated. In this study, steel slit damper, which is widely used in Korea, was considered. The slit dampers with 55kN and 240kN of yielding strength were produced and tested. It was concluded that the slit damper's hysteresis behavior was affected by the dependent characteristics: displacement, velocity and aspect ratio. In other words, the steel slit damper's behavior was stable within limit displacement, and aspect ratio of the strut affected repeated deformation capacity of the damper subjected to large deformation. In addition, it was observed that the repeated deformation capacity abruptly decreased at the high speed range (${\geq}60mm/sec$). Furthermore, the experimental results were evaluated with the criterion of the damping device specified in ASCE7-10.

• 한국철도학회논문집
• /
• 제9권6호
• /
• pp.798-803
• /
• 2006

The suspension elements like primary coil spring, yaw damper, body to body damper are core parts of high speed railway bogie and the faults relating to these elements are reported recently. Thus, this study is started to analyze the displacements characteristics of suspension elements of high speed railway rolling-stock for the purpose of preventing the faults and developing the maintenance technology for suspension elements like spring and dampers. For this purpose, we made a plan to measure the displacements of the primary coil spring, yaw damper and body to body damper in actual running condition. We developed the measurement device to measure the longitudinal displacement and angular displacement of suspension elements and installed this device to test suspension elements. Test to measure displacements of suspension elements is conducted in service line of high speed railway. The displacement data which is acquired from the test with actual vehicles was analyzed for its maximum displacement depending on the track sections. As a result of analysis, we obtained the displacement trends occurring with the sections and valuable results like maximum values and the displacement distribution.

• 한국군사과학기술학회지
• /
• 제24권5호
• /
• pp.545-557
• /
• 2021

Engine is the main source of vibration that generates unwanted noise and vibration of vehicle chassis. Especially, in submarine applications, radiation of noise signatures can be detected at some distance away from the submarine using a sonar array. Thus quiet operation is crucial for submarine's survivability. This study addresses reduction of the force transmissibility originating from engines and transmitted to hull through engine mounts. An inertial damper, as an actuator of hybrid mount system, is addressed to reduce even further the level of vibration. Narrow band FxLMS algorithms are broadly used to cancel the vibration of engine mount because of its excellent performance of canceling narrow band noise. However, in real active dampers, the maximum displacement of damper mass is kinematically restricted. When the control input signal from the FxLMS algorithm exceeds this limitation, the damper mass will collide with the mechanical stops and results in many problems. Originated from these, a modified narrow band FxLMS algorithm based on the equalizer technique with the maximum allowable displacement of active damper mass is proposed in this study. Some simulation results showed that the propose algorithm is effective to suppress vibration of engine mount while ensuring given displacement constraint.

• 한국지진공학회논문집
• /
• 제24권3호
• /
• pp.149-156
• /
• 2020

The vibration control device such as the damper can be used to reinforce the seismic performance of structures. The damper is activated by the deformation of structures during earthquake; however, the deformation of structures is extremely small, causing difficulty in using the damper. Therefore, there is a need for a method capable of amplifying small deformities and transmitting them to the damper. The purpose of this paper is to develop and evaluate a displacement amplification seismic system using cable-pulley. The appropriate cable was selected through a cable tensile performance test and the results of the frame experiment were compared with theoretical displacement amplification ratio values. As a result, it may be said that the proposed system using cable-pulley is useful for displacement amplification.

• 한국안전학회지
• /
• 제27권1호
• /
• pp.70-75
• /
• 2012

For the vibration control of earthquake-excited structures, a pivot-type displacement amplification damper system is proposed and its validity is investigated in this study. A rotational frame amplifies the stroke of the proposed damper system and it can absorb more vibrational energy compared to the conventional dampers of which strokes are not large. In order to prove the effectiveness of the system, time-history analyses are performed with a three story building modelled by a three dimensional frame and numerical results are compared with those for a conventional V-shape braced damper system. In addition, the seismic performances are investigated according to the changes of damper capacity and location.

• Smart Structures and Systems
• /
• 제21권2호
• /
• pp.207-223
• /
• 2018

In this inquisition, a passive damper namely Stockbridge Damper (SBD) has been introduced to the field of vibration control of Offshore Wind Turbine (OWT) to reduce the earthquake excitations. The dynamic responses of the structure have been analyzed for three recorded earthquakes and the responses have been assessed. To find an optimum SBD, the parameters of damper have been optimized using Response Surface Methodology (RSM) based on Box-Behnken Design (BBD) and Particle Swarm Optimization (PSO). The influence of the design variables of SBD such as the diameter of messenger cable, the length of messenger cable and logarithmic decrement of the damping has been investigated through response variables such as maximum displacement, RMS displacement and frequency amplitude of structure under an artificially generated white noise. After that, the structure with optimized and non-optimized damper has been analyzed with under the same earthquakes. Moreover, the comparative results show that the structure with optimized damper is 11.78%, 18.71%, 11.6% and 7.77%, 7.01%, 10.23% more effective than the structure with non-optimized damper with respect to the displacement and frequency response under the earthquakes. The results show that the SBD can obviously affect the characteristics of the vibration of the OWT and RSM based on BBD and PSO approach can provide an optimum damper.

• Steel and Composite Structures
• /
• 제45권5호
• /
• pp.683-695
• /
• 2022

Conventional braces are often used to provide stiffness to structures; however due to buckling they cannot be used as seismic energy dissipating elements. In this study, a seismic energy dissipation device is proposed which is comprised of a bracing member and a steel hysteretic damper made of steel hexagonal plates. The hexagonal shaped designated fuse causes formation of plastic hinges under axial deformation of the brace. The main advantages of this damper compared to conventional metallic dampers and buckling-restrained braces are the stable and controlled energy dissipation capability with ease of manufacture. The mechanical behavior of the damper is formulated first and a design procedure is provided. Next, the theoretical formulation and the efficiency of the damper are verified using finite element (FE) analyses. An analytical model of the damper is established and its efficiency is further investigated by applying it to seismic retrofit of a case study structure. The seismic performance of the structure is evaluated before and after retrofit in terms of maximum interstory drift ratio, top story displacement, residual displacement, and energy dissipation of dampers. Overall, the median of maximum interstory drift ratios is reduced from 3.8% to 1.6% and the residual displacement decreased in the x-direction which corresponds to the predominant mode shape of the structure. The analysis results show that the developed damper can provide cost-effective seismic protection of structures.

• 한국구조물진단유지관리공학회 논문집
• /
• 제17권2호
• /
• pp.62-70
• /
• 2013

본 연구의 목적은 일자형 슬릿형 강재댐퍼보다 에너지 소산능력 등이 우수할 것으로 평가된 꺽쇠형 강재 댐퍼의 변위 및 속도의존성 평가에 있다. 이를 위하여 6개의 시험체를 대상으로 의존성 시험을 수행하였다. 시험변수는 변위의존성 및 속도의존성이다. 변위의존성 시험결과, 큰 목표변위 (50mm)의 반복횟수 및 누적에너지소산능력은 적은 목표변위 (25mm)에 비하여 감소하였다. 또한 짧은 목표변위보다 큰 항복강도 및 조기파단을 나타내었다. 속도의존성 평가에서는 빠른 목표속도(60mm/sec)의 반복횟수 및 누적에너지소산능력이 느린 목표속도 (40mm/sec)에 비하여 감소하였다. 따라서 강재댐퍼의 이력 의존성은 가력 변위 및 속도와 밀접한 연관이 있는 것으로 평가되었다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2016년도 추계 학술논문 발표대회
• /
• pp.11-12
• /
• 2016

Buildings which was constructed before 1988 were not satisfied seismic design code. Thus, most of these buildings have to retrofit for remodeling. This study proposed the steel slit damper system with displacement-amplification device. It could maximize the effectiveness of a damper system in controlling seismic response of a building by amplifying story drift induced to damper. In this study, the proposed system was verified the effect of displacement-amplification using the analytical and experimental study. From the analysis and experiment, it was found that the propsed damping system showed a stable hysteric behavior with excellent energy dissipation capacity. Therefore the proposed system will make a good seismic performance and economical benefits.