scholarly journals LQG Control of Along-Wind Response of a Tall Building with an ATMD

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ki-Pyo You ◽  
Jang-Youl You ◽  
Young-Moon Kim

Modern tall buildings use lighter construction materials that have high strength and less stiffness and are more flexible. Although this results in the improvement of structural safety, excessive wind-induced excitations could lead to occupant discomfort. The optimal control law of a linear quadratic Gaussian (LQG) controller with an active tuned mass damper (ATMD) is used for reducing the along-wind response of a tall building. ATMD consists of a second mass with optimum parameters for tuning frequency and damping ratio of the tuned mass damper (TMD), under the stationary random load, was used. A fluctuating along-wind load, acting on a tall building, was treated as a stationary Gaussian white noise and was simulated numerically, in the time domain, using the along-wind load spectra proposed by G. Solari in 1993. Using this simulated wind load, it was possible to calculate the along-wind responses of a tall building (with and without the ATMD), using an LQG controller. Comparing the RMS (root mean square) response revealed that the numerically simulated along-wind responses, without ATMD, are a good approximation to the closed form response, and that the reduced responses with ATMD and LQG controller were estimated by varying the values of control design parameters.

Author(s):  
S Pourzeynali ◽  
S Salimi

In engineering applications, many control devices have been developed to reduce the vibrations of structures. Active tuned mass damper system is one of these devices, which is a combination of a passive tuned mass damper system and an actuator to produce a control force. The main objective of this paper is to present a practical procedure for both deterministic and probabilistic design of the active tuned mass damper control system using multi-objective genetic algorithms to mitigate high-rise building responses. For this purpose, extensive numerical analyses have been performed, and optimal robust results of the active tuned mass damper design parameters with their effectiveness in reducing the example building responses have been presented. Uncertainties, which may exist in the system, have been taken into account using a robust design optimization procedure. The stiffness matrix and damping ratio of the building are considered as uncertain random variables; and using the well-known beta distribution, 50 pairs of these variables are generated. This resulted in 50 buildings with different stiffness matrices and damping ratios. These simulated buildings are used to evaluate robust optimal values of the active tuned mass damper design parameters. Four non-commensurable objective functions, namely maximum displacement, maximum velocity, maximum acceleration of each floor of the building, and active control force produced by the actuator are considered, and a fast and elitist non-dominated sorting genetic algorithm approach is used to find a set of pareto-optimal solutions.


2013 ◽  
Vol 650 ◽  
pp. 667-672 ◽  
Author(s):  
Dong Keon Kim ◽  
Jong Wan Hu

Occurrence of frequency of earthquakes around the world has been increased including Sendai earthquake in Japan and magnitude of earthquake has also increased. Recently, many tall buildings using local seismic codes can be exposed to the risk of an earthquake and wind. Also, some buildings, which was planned to be built, were foundered as a result of lack of finance. Therefore, for tall buildings, structural safety such as earthquake and wind resistant performance, and financing issue are very important to progress the huge project. So we need to find another optimum alternative other than damping devices and base isolation system. In this study, four types of test specimens are used, which are fifty-story base tall building, tall building that was reinforced with diagonal brace, x-brace, and Chevron brace. And all of these cases, are subjected to the seismic load and wind load, finally analyzed and compared for seismic and wind performances.


2014 ◽  
Vol 935 ◽  
pp. 211-214 ◽  
Author(s):  
Dong Liang ◽  
Ji Xiang Song

The commonly used viscous dampers for cable’s vibration mitigation have some unfavorable factors, such as the damping effect is not obvious for super long stay cable, the limitation of installation position, coupling vibration, etc. The cable-tuned mass damper system vibration model is put forward to solve this problem. The optimal cable-tuned mass damper system modal damping ratio and optimum design parameters, including cable vibration order, TMD’s stiffness, TMD’s mass, and TMD’s damping, were obtained by the method of complex models. The results can provide important reference for the design of TMD for stay cable.


2014 ◽  
Vol 1004-1005 ◽  
pp. 1602-1607
Author(s):  
Young Moon Kim ◽  
Ki Pyo You ◽  
Jang Youl You

Modern tall buildings are more flexible so occur excessive wind-induced vibration resulting in occupant discomfort and structural safety. Many studies to reduce such a wind-induced vibration using a feedback controller and auxiliary devices have been conducted .The optimal control law of linear quadratic Gaussian (LQG) controller is used for reducing the across-wind vibration response of a tall building with an active mass damper (AMD). Fluctuating across-wind load treated as a Gaussian white noise process is simulated numerically in time domain. And using this simulated across-wind load estimated across-wind vibration responses of tall building with AMD using LQG controller.


2013 ◽  
Vol 421 ◽  
pp. 767-771 ◽  
Author(s):  
Young Moon Kim ◽  
Ki Pyo You ◽  
Jang Youl You ◽  
Sun Young Paek ◽  
Byung Hee Nam

Modern tall buildings using high strength and lighter construction materials are more flexible so could be excessive wind-induced vibrations resulting in occupant discomfort and structural unsafety. Recently, many studies have been advanced in using actuator force as an active control force based on the linear quadratic optimum control theory .It needs to predict the wind-induced response and the optimum control force to reduce the excessive wind-induced vibration. It takes a lot of time and cost to do wind tunnel test needed it, so numerical simulation approach instead of that is recommended sometimes. Simulating wind load in the time domain using known spectra data of fluctuating wind load is particularly useful for some prediction of windinduced vibration which is more or less narrow banded process such as a along-wind response of a tall building. In this study, fluctuating along-wind load acting on a tall building treated as a stationary Gaussian white noise process was simulated numerically in the time domain using the along-wind load spectra proposed by G.Solari in1992. And using this simulated along-wind load estimated the reduced along-wind vibration response of a tall building which has an active tuned mass damper (ATMD) installed based on the linear quadratic regulator (LQR) control method.


2020 ◽  
pp. 195-198
Author(s):  
Mohammad Shamim Miah

This study investigates the performance of tall buildings using tuned mass damper (TMD) under dynamic loads such as harmonic loads, and the Loma Prieta Earthquake 1989 data. The numerical investigations are performed by considering a sixteen-storied dynamical system. To do this end, the aforementioned system is considered to be uncontrolled (meaning no damper is used) and a controlled case is assumed where a TMD is placed on the top floor. TMD performance mainly relies on the set of parameters (mass ratio, damping ratio, and stiffness). In reality, the tuning process of those parameters take serious effort and gets worse with the complicacy of the structure. Hence to obtain better performance of the TMD the damping ratio and the frequency of the TMD are optimized by using unconstrained derivative-free method. Finally, the uncontrolled and controlled performance of the sixteen-storied structure has been evaluated and compared. The results show that the dynamical response of the studied problem can be reduced significantly via the use of optimized parameters.


2016 ◽  
Vol 723 ◽  
pp. 753-759
Author(s):  
Young Moon Kim ◽  
Ki Pyo You ◽  
Jang Youl You ◽  
Sun Young Paek ◽  
Byung Hee Nam

A composite tuned mass damper(CTMD) is a vibration control device consisting of an active-passive tuned mass dampers supported on the primary vibrating structure. The performance of CTMD in mitigating wind-induced vibration of tall building is investigated. Optimum parameters of a passive tuned mass damper(PTMD)for minimizing the variance response of the damped primary structure under random loads, with different mass ratio of an active tuned mass damper(ATMD) to a PTMD have been used for the optimum parameters of CTMD. The active control force generated by ATMD actuator was estimated by using linear quadratic Gaussian(LQG) controller, and the fluctuating along-wind load, treated as a stationary random process ,was simulated numerically using the along-wind load spectrum proposed by Solari .Comparing the along-wind rms response of tall building without a CTMD, the CTMD is effective in reducing the response to 40%~45% of the response without the CTMD. Therefore, the CTMD system was effective in reducing wind-induced vibration of tall building.


2013 ◽  
Vol 823 ◽  
pp. 396-401
Author(s):  
Young Moon Kim ◽  
Ki Pyo You ◽  
Jang Youl You

Modern tall buildings using high strength and lighter construction materials are more flexible so could be excessive wind-induced vibrations resulting in occupant discomfort and structural unsafety . Recently, many studies have been advanced in using actuator force as an active control force based on the linear quadratic optimum control theory. It needs to predict the wind-induced response and the optimum control force to reduce the excessive wind-induced vibration. It takes a lot of time and cost to do wind tunnel test needed it, so numerical simulation approach instead of that is recommended sometimes. Simulating wind load in the time domain using known spectra data of fluctuating wind load is particularly useful for some prediction of windinduced vibration which is more or less narrow banded process such as across-wind response of a tall building. The simulation procedure is taken from Deodatis. In this study, fluctuating across-wind load acting on a tall building was simulated numerically in the time domain using the across-wind load spectra proposed by A.Kareem in1982. And using this simulated across-wind load estimated the reduced across-wind vibration response of a tall building using the linear quadratic Gaussian (LQG) control method.


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