• 대한기계학회논문집A
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• 제28권11호
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• pp.1656-1663
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• 2004

As the structures become larger, higher and more complicated, the demand for safety level has increased. In recent years, TLD(Tuned Liquid Damper) proved to be a successful control tool for reducing structural vibrations. For this reason, the influence of some key parameters of the U-type TLD on the dynamic response is studied. And simple and effectively developed learning control logic is used to control vibration of U type Tuned Liquid Damper system. The purpose of this paper is design optimal control system to deal with unknown errors from non linearity and variation that cost modeling difficulty in complex structure and is followed with the desired behavior. Finally this hybrid control method applied to U type Tuned Liquid Damper structure gives the benefit from better performance of precision and stability of the structure by reducing vibration effect. This research leads to safety design in various structure to robust unspecified foreign disturbances such as windy-load and earthquake.

• Smart Structures and Systems
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• 제4권5호
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• pp.667-684
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• 2008

Numerous devices exist for reducing or eliminating seismic damage to structures. These include passive dampers, semi-active dampers, and active control devices. The performance of structural systems with these devices has often been evaluated using numerical simulations. Experiments on structural systems with these devices, particularly at large-scale, are lacking. This paper describes a real-time hybrid testing facility that has been developed at the Lehigh University NEES Equipment Site. The facility enables real-time large-scale experiments to be performed on structural systems with rate-dependent devices, thereby permitting a more complete evaluation of the seismic performance of the devices and their effectiveness in seismic hazard reduction. The hardware and integrated control architecture for hybrid testing developed at the facility are presented. An application involving the use of passive elastomeric dampers in a three story moment resisting frame subjected to earthquake ground motions is presented. The experiment focused on a test structure consisting of the damper and diagonal bracing, which was coupled to a nonlinear analytical model of the remaining part of the structure (i.e., the moment resisting frame). A tracking indictor is used to track the actuator ability to achieve the command displacement during a test, enabling the quality of the test results to be assessed. An extension of the testbed to the real-time hybrid testing of smart structures with semi-active dampers is described.

• Smart Structures and Systems
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• 제19권4호
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• pp.341-350
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• 2017

Based on the super elastic properties of the shape memory alloy (SMA) and the inverse piezoelectric effect of piezoelectric (PZT) ceramics, a kind of hybrid semi-active control device was designed and made, its mechanical properties test was done under different frequency and different voltage. The local search ability of genetic algorithm is poor, which would fall into the defect of prematurity easily. A kind of adaptive immune memory cloning algorithm(AIMCA) was proposed based on the simulation of clone selection and immune memory process. It can adjust the mutation probability and clone scale adaptively through the way of introducing memory cell and antibody incentive degrees. And performance indicator based on the modal controllable degree was taken as antigen-antibody affinity function, the optimization analysis of damper layout in a space truss structure was done. The structural seismic response was analyzed by applying the neural network prediction model and T-S fuzzy logic. Results show that SMA and PZT friction composite damper has a good energy dissipation capacity and stable performance, the bigger voltage, the better energy dissipation ability. Compared with genetic algorithm, the adaptive immune memory clone algorithm overcomes the problem of prematurity effectively. Besides, it has stronger global searching ability, better population diversity and faster convergence speed, makes the damper has a better arrangement position in structural dampers optimization leading to the better damping effect.

• 한국강구조학회 논문집
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• 제21권1호
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• pp.83-91
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• 2009

비좌굴가새는 우수한 내진성능을 보이는 시스템이다. 그러나 비좌굴가새는 약진이나 바람과 같은 하중에 대하여 에너지를 소산시키지 못한다. 기존의 비좌굴가새의 풍저항 성능을 개선한 하이브리드 비좌굴가새(H-BRB)는 비좌굴가새와 점탄성댐퍼로 구성된 복합댐퍼시스템의 일종이다. 본 논문에서는 탄성영역에서 H-BRB의 구조성능을 확인하기 위하여 심재가 다른 두 개의 실험체에 대한 실험이 수행되었다. H-BRB 시스템에 대한 탄성영역에서의 거동메케니즘 검증을 위하여 주저항요소와 2차 저항요소의 축변형량과 에너지소산 능력을 비교하였다. 실험결과 댐퍼부에서 이면전단을 사용한 H-BRB는 우수한 구조성능을 보이며, 고층건물의 사용성 수준을 향상시키기 위하여 적용될 수 있을 것이다.

• Earthquakes and Structures
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• 제4권1호
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• pp.63-84
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• 2013

A semi-active mass damping (SMD) system with magnetorheological (MR) dampers focusing on low- and mid-rise buildings is proposed in this paper. The main purpose of this study is to integrate the reliable characteristics of the traditional tuned mass damper (TMD) and the superior performance of the active mass damper (AMD) to the new system. In addition, the commonly seen solution of deploying dense seismic dampers throughout the structure nowadays to protect the main structure is also expected to switch to the developed SMD system on the roof with a similar reduction performance. In order to demonstrate this concept, a full-size three-story steel building representing a typical mid-rise building was used as the benchmark structure to verify its performance in real life. A numerical model with the interpolation technique integrated was first established to accurately predict the behavior of the MR dampers. The success of the method was proven through a performance test of the designated MR damper used in this research. With the support of the MR damper model, a specific control algorithm using a continuous-optimal control concept was then developed to protect the main structure while the response of the semi-active mass damper is discarded. The theoretical analysis and the experimental verification from a shaking table test both demonstrated the superior mitigation ability of the method. The proposed SMD system has been demonstrated to be readily implemented in practice.

• 한국지진공학회논문집
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• 제17권3호
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• pp.143-150
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• 2013

The paper introduces Multi-Platform Analysis (MPA) for the seismic performance of a structure controlled by Magneto-Rheological (MR) dampers and presents analytical assessment of the effect of MR damper when taking into account nonlinear behavior of the structure. This paper introduces the MR Damper Plugin that can facilitate communication between MATLAB/Simulink and a finite element analysis tool in order to account for more complex inelastic behavior of the structure with MR dampers. The MPA method using the developed MR Damper Plugin is validated with experimental results from the real-time hybrid simulation. By utilizing the proposed MPA method, the three-story RC structure controlled by MR dampers is more realistically modeled and its performance under seismic loads is investigated. It is concluded that MR damper designed for a linear structure is not effective in a nonlinear structure and can overestimate the effect of MR damper. This work is expected to overcome difficulties in the analytical assessment of structural control strategies for complex and nonlinear structures by obtaining more reliable results.

• Smart Structures and Systems
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• 제14권6호
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• pp.1031-1054
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• 2014

Real-time hybrid simulation (RTHS) of a stacked wood shear wall retrofitted with a rate-dependent seismic energy dissipation device (viscous damper) was conducted at the newly constructed Structural Engineering Laboratory at the University of Alabama. This paper describes the implementation process of the RTHS focusing on the controller scheme development. An incremental approach was adopted starting from a controller for the conventional slow pseudodynamic hybrid simulation and evolving to the one applicable for RTHS. Both benchmark-scale and full-scale tests are discussed to provide a roadmap for future RTHS implementation at different laboratories and/or on different structural systems. The developed RTHS controller was applied to study the effect of a rate-dependent energy dissipation device on the seismic performance of a multi-story wood shear wall system. The test specimen, setup, program and results are presented with emphasis given to inter-story drift response. At 100% DBE the RTHS showed that the multi-story shear wall with the damper had 32% less inter-story drift and was noticeably less damaged than its un-damped specimen counterpart.

• Smart Structures and Systems
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• 제32권6호
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• pp.349-358
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• 2023

Real-Time Hybrid Testing (RTHT) requires the numerical substructure calculations to be completed within the defined integration time interval due to its real-time loading demands. For solving the problem, A Real-Time Hybrid Testing based on Restart-Loading Technology (RTHT-RLT) is proposed in this paper. In the proposed method, in case of the numerical substructure calculations cannot be completed within the defined integration time interval, the experimental substructure was returned back to the initial state statically. When the newest loading commands were calculated by the numerical substructure, the experimental substructure was restarted loading from the initial state to the newest loading commands so as to precisely disclosing the dynamic performance of the experimental substructure. Firstly, the methodology of the RTHT-RLT is proposed. Furthermore, the numerical simulations and experimental tests on one frame structure with a viscous damper are conducted for evaluating the feasibility and effectiveness of the proposed RTHT-RLT. It is shown that the proposed RTHT-RLT innovatively renders the nonreal-time refined calculation of the numerical substructure feasible for the RTHT. The numerical and experimental results show that the proposed RTHT-RLT exhibits excellent performance in terms of stability and accuracy. The proposed RTHT-RLT may have broad application prospects for precisely investigating the dynamic behavior of large and complex engineering structures with specific experimental substructure where a restarting procedure does not affect the relevant hysteretic response.

• 한국구조물진단유지관리공학회 논문집
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• 제10권4호
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• pp.108-118
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• 2006

본 연구는 지진동을 받는 구조물의 응답을 제어하기 위한 하이브리드 LQG 기법의 효용성을 조사하는 것이 목적이다. 입력 기진력은 엘센트로 지진이며 지반 가속도을 적절히 조절하여 구조물이 탄성 범위내에서 거동하도록 하였다. 수동 제어 장치로서 최상층에 설계된 TMD는 LQG 제어 알고리즘에 의해 통제되며 능동 제어기와 함께 하이브리드 제어 시스템을 이룬다. 이 기법을 통해 제어된 변위 응답을 비교한 결과 순수하게 능동 제어를 한 경우에 비해 훨씬 작은 크기의 입력으로도 변위를 제어할 수 있었으며 센서의 위치는 최상층에 부착하는 것이 가장 효과적인 것으로 나타났다.

• 한국자동차공학회논문집
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• 제19권1호
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• pp.17-24
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• 2011

TMED(Transmission Mounted Electric Device) parallel hybrid configuration can realize EV(Electric Vehicle) mode by disengaging the clutch between an engine and a transmission-mounted motor to improve efficiencies of low load driving and regenerative braking. In the EV mode, however, jerk can be induced since there are insufficient damping elements in the drive-train. Though the jerk gives demoralizing influence upon driving comport, adding a physical damper is not applicable due to constraints of the layout. This study suggests the jerk reduction control, composed of active damping method and torque profiling method, to suppress the jerk without hardware modification. The former method creates a virtual damper by generating absorbing torque in the opposite direction of the oscillation. The latter method reduces impulse on the mated gear teeth of the drive-train by limiting the gradient of traction torque when the direction of the torque is reversed. To validate the effectiveness of the suggested strategy, a series of vehicle tests are carried out and it is observed that the amplitude of the oscillation can be reduced by up to 83%.