• 드라이브 ㆍ 컨트롤
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• 제14권1호
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• pp.8-13
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• 2017

This paper proposes a hydraulic circuit for a Magnetorheological (MR) damper that can be used for semi-active and active controls. Methods are presented for obtaining reliable damping force displacement and velocity data, and hysteresis loop data corresponding to applied current. In order to get reliable data, analysis using electric and electronic software, a series of tests. and comparative evaluations are required. A hydraulic circuit model is proposed that can be applied to analyze a MR damper without any assumptions where the yield stress data according to the applied current are known. Analysis results of the proposed hydraulic circuit are confirmed by experimental results within acceptable tolerance. This hydraulic circuit model can be applied to various MR dampers and systems.

• 한국소음진동공학회논문집
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• 제20권6호
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• pp.528-536
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• 2010

System identification for cylindrical oil dampers is carried out based on a series of dynamic experimental tests and theoretical approach for the analysis of the experimental data. Experimental tests are conducted using a specific hydraulic actuator in the wide frequency range from 10 Hz to 90 Hz. From this study, it is confirmed that control force of the damper is composed of inertia, damping and restoring components. In general, both restoring and damping components are significant and comparable. However, the portion of the inertia components becomes more significant than to be negligible in the high frequency range.

• 한국산업융합학회 논문집
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• 제13권1호
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• pp.15-22
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• 2010

This paper was originated to set up a test equipment and to obtain the proper installation condition of the plastic damper for the hydraulic clutch control system. Performance tests with different specifications have been applied to the damper to investigate the workability and the vibration characteristics of each case, and the result was utilized into the system simulation for the optimal condition for the damper. The procedure has been developed to set up a damper test system to analyze the dynamic properties and the operation of the system, and further to setup a simulation program for the realistic situations. The result can also be applied to the dampers and the clutch systems to be developed in the future for the property tests and the optimization of the installation conditions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.343-353
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• 1997

This study had been performed to estimate for vibration characteristics of the Power Motor Coaches with Diesel-Hydraulic Drive and to secure a dynamic characteristic construction technology of another rolling stock. Air bags, springs and dampers of Bogie are carefully reviewed in order to improve ride quality. Dynamic analysis had been performed using VAMPIRE program, which had been developed by BRR, and the analysis results had been compared with test data to verify.

• Earthquakes and Structures
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• 제12권5호
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• pp.479-487
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• 2017

Frictional dampers are used in structural engineering as means of passive control. Meanwhile, frictional damper shave a disadvantage compared to viscous rivals since the slippage force must be exceeded to activate the device, and cannot be ideal full range of possible events. The concept of semi-active control is utilized to overcome this shortcoming. In this paper, a new semi-active frictional damper called Smart Adjustable Frictional (SAF) damper is introduced. SAF damper consists of hydraulic, electronic units and sensors which are all linked with an active control discipline. SAF acts as a smart damper which can adapt its slippage threshold during a dynamic excitation by measuring and controlling the structural response. The novelty of this damper is, while it controls the response of the structure in real time with acceptable time delay. The paper also reports on the results of a series of experiments which have been performed on SAF dampers to obtain their prescribed hysteretic behavior for various control algorithms. The results show that SAF can produce the desired slippage load of various algorithms in real time. Numerical models incorporating control simulations are also made to obtain the hysteretic response of the system which agrees closely with test results.

• 한국지진공학회논문집
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• 제8권3호
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• pp.63-76
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• 2004

사장교에 발생하는 지진에 의한 진동을 감소시키기 위해 추가적인 능동/반능동 제어장치를 부착한 LRB-기반 복합 기초격리 시스템에 대한 논문이다. 복합 기초격리 시스템은 제어장치가 다중으로 작동하기 때문에 LRB가 설치된 교량 시스템과 같은 수동형 기초격리 시스템에 비해 제어 성능이 뛰어나다. 본 논문에서는, LQG 알고리듬에 의해 제어되는 능동형 유압식 가력기와 clipped 최적제어에 의해 제어되는 반능동형 자기유변 유체 (MR) 감쇠기를 추가적인 제어장치로 고려하여 추가적인 응답 감소 효과를 검토하였다. 이를 위해, 미국토목학회의 1단계 벤치마크 사장교에 LRB를 설치한 교량을 고려하였다. 수치해석 결과를 통해, 모든 LRB-기반 복합 기초격리시스템이 구조물의 응답을 효과적으로 감소시킴을 확인하였다. 또한, MR 감쇠기를 채택한 복합 기초격리 시스템은 구조물 강성의 불확실성에 대해 강인성을 보였지만 유압식 가력기를 채택한 경우에는 강인성이 부족함을 알 수 있었다. 따라서, 반능동형 추가 제어장치를 채택한 복합 기초격리 시스템의 대형 토목구조물에 대한 적용가능성이 제어 성능 및 강인성 면에서 분명하게 검증되었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.560-564
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• 2007

In order to reduce the level of recoil force, new recoil technology must be employed. The present study discusses a soft-recoil mechanism that can reduce dramatically the recoil force. The dynamics of the soft-recoil system with hydraulic dampers are described and simulated. The results of the simulation show that FOOB system can reduce the recoil force and the recoil stroke compared to conventional systems. However, the FOOB system is not able to perform well when the fault modes happen. Hence, this study uses the MR damper to achieving FOOB under fault modes.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.527-534
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• 2003

This paper presents the LRB-based hybrid base isolation systems employing additional active/semiactive control devices for seismic protection of cable-stayed bridges by examining the ASCE first generation benchmark problem for a cable-stayed bridge. In this study, ideal hydraulic actuators (HAs) and ideal magnetorheological dampers (MRDs) are considered as additional active and semiactive control devices, respectively. Numerical simulation results show that all the hybrid base isolation systems are effective in reducing the structural responses of the benchmark cable-stayed bridge under the historical earthquakes considered. The simulation results also demonstrate that the hybrid base isolation system employing semiactive MRBs is robust to the stiffness uncertainty of the structure, while the hybrid system with active HAs is not. Therefore, the LRB-based hybrid base isolation system employing MRDs could be more appropriate in real applications for full-scale civil infrastructures.

• 국제초고층학회논문집
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• 제10권2호
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• pp.99-107
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• 2021

This research investigates the potential of Adaptive TMDs for tall building damping. The Adaptive TMD under consideration is based on real-time controlled hydraulic dampers generating purely dissipative control forces. The control approach is designed to enhance the Adaptive TMD efficiency for moderate wind loads with return periods below 50 years. The resulting enhanced TMD efficiency is used to reduce the pendulum mass by 15% compared to the passive TMD while still guaranteeing the acceleration limits of the one and ten year return period winds. Furthermore, the adaptive control approach is designed to disproportionally increase the controlled damping force at wind loads with return periods of 50 years and more in order to reduce the maximum relative motion of the Adaptive TMD with only 85% pendulum mass. Compared to the passive TMD with 100% pendulum mass the maximum relative motion is reduced by 20%. Both the pendulum mass reduction and the maximum relative motion reduction significantly reduce the foot print of the Adaptive TMD which is highly desirable from the economic point of view.

• 대한기계학회논문집
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• 제10권5호
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• pp.689-697
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• 1986

본 연구에서는 3자유도(3방향의 병진운동만 고려) 고무마운트모형의 타당성을 검증하기 위하여, 먼저 고무자체의 물성치인 강성계수와 감쇠계수를 진동수와 초기변 형률에 따라 실험을 통해 구하였다. 질량행렬의 모든요소를 쉽게 구할 수 있는 간단 한 시험구조물을 제작하고 여기에 고무아운트를 부착하여 6자유도를 갖는 모의 엔진- 마운트계를 구성한 후 가진실험을 통해 얻은 오무드 매개변수들과 고무의 물성치를 이 용한 컴퓨터 시뮬레이션의 결과를 비교함으로써 고무아운트 모형의 타당성을 검증하였 다. 특히 본 연구에는 유압가진 실험으로부터 얻은 실험결과를 바탕으로 고무의 강 성계수를 주파수의 1차함수로 고려한 경우와 전진동수 영역에서 균일하다고 가정하는 경우를 비교하였다.