Study on the Stability of Non-Structural Element Using Active Tuned Mass Damper

2020 ◽  
Vol 17 (7) ◽  
pp. 3224-3230
Author(s):  
Hong-Won Kim ◽  
Dong-Gi Kwag

Currently, the frequency of earthquakes is increasing in Korea, but due to the lack of appropriate seismic equipment, significant damage is expected. In order to solve this problem, active tuned mass damper will be developed to reduce earthquake damage in response to seismic waves, which are combined from low frequency to high frequency. In this paper, various control methods are introduced to reduce the amplitude ratio occurring at the 1st and 2nd natural frequencies for 3 DOF nonstructural elements. Through mathematical modeling, we confirm how each control method is applied and present the problems of the existing passive tuned mass damper and suggest the active tuned mass damper. To induce an active copper reducer, the response according to the control method can be predicted with a focus on the energy change rate. The active controller receives feedback from the relative displacement and relative velocity of the structure and uses it as a variable to set the control method. The passive control method and the active control method are compared through the simulation, and excellent control performance can be confirmed in the high frequency region as well as the second natural frequency. Vibration reduction performance was confirmed by each control method and the most ideal control method was selected. The optimum vibration reduction performance can be confirmed by using the signal function to always generate 180° of phase difference with respect to the speed of the structure. Not only earthquake but also mechanical vibration, wind load, etc., it can be used in all fields where damage is caused by excitation force inherent in various complex frequencies.

2019 ◽  
Vol 7 (7) ◽  
pp. 224 ◽  
Author(s):  
Wenhua Wang ◽  
Xin Li ◽  
Zuxing Pan ◽  
Zhixin Zhao

The dynamic characteristics of a bottom-fixed offshore wind turbine (OWT) under earthquakes are analyzed by developing an integrated analysis model of the OWT. Further, the influence of the interactions between the rotor and support system on the structural responses of the OWT subjected to an earthquake is discussed. Moreover, a passive control method using a tuned mass damper (TMD) is applied to the OWT to control the responses under earthquakes. The effects of the mass ratio, location and tuned frequency of the TMD on controlling structural responses of the OWT under different recorded seismic waves are studied.


2011 ◽  
Vol 243-249 ◽  
pp. 5197-5203
Author(s):  
Zhi Qiang Zhang ◽  
Fei Ma

In this paper, Hefei TV Tower is used as an analytical case to examine the Hybrid control method on seismic response. Firstly, on the basis of the other’s work, a bi-model dynamic model is proposed to study the seismic response vibration hybrid control, using tuned mass damper and viscous fluid dampers. Then the optimal coefficient is obtained by considered the seismic response of upper turret as optimization objectives. According to analysis, it’s showed that the seismic responses of the tower are decreased greatly with tuned mass damper and viscous fluid dampers, and the vibration reduction effectiveness of the tower is sensitive to the spectral characteristics of earthquake wave.


Author(s):  
Wenhua Wang ◽  
Zhen Gao ◽  
Xin Li ◽  
Torgeir Moan ◽  
Bin Wang

The finite element model (FEM) of a pentapod offshore wind turbine (OWT) is established in the newly compiled FAST. The dynamic responses of the OWT are analyzed in detail. Further, a tuned mass damper as a passive control strategy is applied in order to reduce the OWT responses under seismic loads. The influence of the tuned mass damper (TMD) locations, mass and control frequencies on the reduction of OWT responses are investigated. A general configuration of TMD can effectively reduce the local and global responses to some degree, but due to the complexity of characteristics of the OWT structure and seismic waves, the single TMD can not obtain consistent controlling effects.


Author(s):  
Duy-Chinh Nguyen

In this paper, an analytical method is presented to determine the optimal parameters of the symmetric tuned mass damper, such as the ratio between natural frequency of tuned mass damper and shaft (tuning ratio) and the ratio of the viscous coefficient of tuned mass damper (damping ratio). The optimal parameters of tuned mass damper are applied to reduce the torsional vibration of the shaft based on consideration of the vibration duration and stability criterion. The dynamic equations of the shaft are provided via Lagrangian equations, and the optimal parameters of tuned mass damper are derived by using the principle of minimum kinetic energy. Analytical and numerical examples are implemented to verify the reliability of the proposed method. The analytical and numerical results indicate that the optimal parameters of tuned mass damper have significant effects in the torsional vibration reduction of the shaft.


2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Xiaohan Wu ◽  
Jun Wang ◽  
Jiangyong Zhou

A high four-tower structure is interconnected with a long sky corridor bridge on the top floor. To reduce the earthquake responses and member forces of the towers and sky corridor bridge, a passive control strategy with a friction pendulum tuned mass damper (FPTMD) was adopted. The sky corridor bridge was as the mass of FPTMD. The connection between the towers and the sky corridor bridge was designed as flexible links, where friction pendulum bearings (FPBs) and viscous dampers were installed. Elastoplastic time-history analysis was conducted by using Perform-3D model to look into its seismic behavior under intensive seismic excitation. The optimal design of the FPTMD with varying friction coefficients and radius of friction pendulum bearing (FPB) under seismic excitations was carried out, and the seismic behavior of the structure was also investigated at the same time.Results show that, for this four-tower connected structure, the friction pendulum tuned mass damper (FPTMD) has very well effect on seismic reduction. The structure can meet the seismic resistance design requirements.


2019 ◽  
Vol 26 (11-12) ◽  
pp. 1054-1067 ◽  
Author(s):  
Seyyed Hossein Hossein Lavassani ◽  
Hamed Alizadeh ◽  
Peyman Homami

Suspension bridges are structures that because of their long span and high flexibility can be prone to ambient vibrations such as ground motions. They can experience high amplitude vibrations in torsional mode during an earthquake, where a vibration control strategy seems necessary. Recently, control systems have been widely used to mitigate vibration of structures. Tuned mass damper is a passive control system. Its performance and effectiveness have been verified both theoretically and practically. In this study, a tuned mass damper system is used to mitigate the torsional vibration of a suspension bridge. The Vincent Thomas suspension bridge is selected as a case study, and its response is reduced by a tuned mass damper under ten pulse-type records from 10 major worldwide earthquakes. By using sensitivity analysis, a parametric study is carried out to optimize tuned mass damper parameters, namely, mass ratio, gyration radius, tuning frequency, and damping ratio according to the maximum reduction of the response maxima. Finally, the optimum range of each parameter that can give the best performance and provide both operational and economic justification for the implementation of the project is suggested. The numerical results indicate that the optimized tuned mass damper system can substantially reduce the maximum response and vibration time.


2020 ◽  
Vol 26 (9-10) ◽  
pp. 646-658
Author(s):  
Lu-yu Li ◽  
Tianjiao Zhang

A tuned mass damper is a passive control device that has been widely used in aerospace, mechanical, and civil engineering as well as many other fields. Tuned mass dampers have been studied and improved over the course of many years. In practical engineering applications, a tuned mass damper inevitably produces some nonlinear characteristics due to the large displacement and the use of the limiting devices, but this nonlinearity is often neglected. The simulation results in this study confirm that neglecting the nonlinearity in the design process can produce adverse effects on the control performance. This paper takes into account the nonlinearity of the tuned mass damper produced in the process of vibration and deduces an optimum formula for the frequency of a tuned mass damper by the complexification averaging method and multiscale method. Based on this formula, a modified design method for the frequency of a tuned mass damper is presented. The numerical results show that the nonlinear tuned mass damper after modification is better than a linear tuned mass damper in terms of control performance.


2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Abdollah Javidialesaadi ◽  
Nicholas E. Wierschem

In this study, a novel passive vibration control device, the three-element vibration absorber–inerter (TEVAI) is proposed. Inerter-based vibration absorbers, which utilize a mass that rotates due to relative translational motion, have recently been developed to take advantage of the potential high inertial mass (inertance) of a relatively small mass in rotation. In this work, a novel configuration of an inerter-based absorber is proposed, and its effectiveness at suppressing the vibration of a single-degree-of-freedom system is investigated. The proposed device is a development of two current passive devices: the tuned-mass-damper–inerter (TMDI), which is an inerter-base tuned mass damper (TMD), and the three-element dynamic vibration absorber (TEVA). Closed-form optimization solutions for this device connected to a single-degree-of-freedom primary structure and loaded with random base excitation are developed and presented. Furthermore, the effectiveness of this novel device, in comparison to the traditional TMD, TEVA, and TMDI, is also investigated. The results of this study demonstrate that the TEVAI possesses superior performance in the reduction of the maximum and root-mean-square (RMS) response of the underlying structure in comparison to the TMD, TEVA, and TMDI.


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