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Mass Damper (mass + damper)

Distribution by Scientific Domains
Engineering100%

Kinds of Mass Damper

  • tuned mass damper
    		•

    Selected Abstracts

    Java-powered virtual laboratories for earthquake engineering education

    COMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2005
    Y. Gao
    Abstract This paper presents a series of Java-Powered Virtual Laboratories (VLs), which have been developed to provide a means for on-line interactive experiments for undergraduate and graduate education. These VLs intend to provide a conceptual understanding of a wide range of topics related to earthquake engineering, including structural control using the tuned mass damper (TMD) and the hybrid mass damper (HMD), linear and nonlinear base isolation system, and nonlinear structural dynamic analysis of multi-story buildings. A total of five VLs are currently available on-line at: http://cee.uiuc.edu/sstl/java and have been incorporated as a reference implementation of educational modules in the NEESgrid software (http://www.neesgrid.org/). © 2005 Wiley Periodicals, Inc. Comput Appl Eng Educ 13: 200,212, 2005; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20050 [source]

    Probabilistic Approach for Nonlinear Modal Control of MDOF Structures Subjected to Multiple Excitations

    COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 1 2005
    Kyung-Won Min
    For the modal control of the MDOF structure, a new eigenvalue assignment algorithm that modifies the dynamic characteristics of only the specific mode is proposed. For the probabilistic evaluation of the proposed nonlinear modal control, the joint probability density function (PDF) of the equivalent nonlinearly controlled single-degree-of-freedom (SDOF) system is obtained by the solution of the reduced Fokker,Planck equation for the equivalent nonlinear system. To overcome the difficulty in the application of the joint PDF to the MDOF structure controlled by the hybrid mass damper (HMD) system and subjected to multiple excitations, the equivalent damping ratio is proposed. The results of the analysis indicate that the proposed nonlinear modal control strategy is effective for the control of MDOF structures requiring a significantly smaller peak control force than the linear quadratic Gaussian (LQG) controller to produce a similar control performance level. [source]

    Protection of seismic structures using semi-active friction TMD

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2010
    Chi-Chang Lin
    Abstract Although the design and applications of linear tuned mass damper (TMD) systems are well developed, nonlinear TMD systems are still in the developing stage. Energy dissipation via friction mechanisms is an effective means for mitigating the vibration of seismic structures. A friction-type TMD, i.e. a nonlinear TMD, has the advantages of energy dissipation via a friction mechanism without requiring additional damping devices. However, a passive-friction TMD (PF-TMD) has such disadvantages as a fixed and pre-determined slip load and may lose its tuning and energy dissipation abilities when it is in the stick state. A novel semi-active-friction TMD (SAF-TMD) is used to overcome these disadvantages. The proposed SAF-TMD has the following features. (1) The frictional force of the SAF-TMD can be regulated in accordance with system responses. (2) The frictional force can be amplified via a braking mechanism. (3) A large TMD stroke can be utilized to enhance control performance. A non-sticking friction control law, which can keep the SAF-TMD activated throughout an earthquake with an arbitrary intensity, was applied. The performance of the PF-TMD and SAF-TMD systems in protecting seismic structures was investigated numerically. The results demonstrate that the SAF-TMD performs better than the PF-TMD and can prevent a residual stroke that may occur in a PF-TMD system. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Particle swarm optimization of TMD by non-stationary base excitation during earthquake

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 9 2008
    A. Y. T. Leung
    Abstract There are many traditional methods to find the optimum parameters of a tuned mass damper (TMD) subject to stationary base excitations. It is very difficult to obtain the optimum parameters of a TMD subject to non-stationary base excitations using these traditional optimization techniques. In this paper, by applying particle swarm optimization (PSO) algorithm as a novel evolutionary algorithm, the optimum parameters including the optimum mass ratio, damper damping and tuning frequency of the TMD system attached to a viscously damped single-degree-of-freedom main system subject to non-stationary excitation can be obtained when taking either the displacement or the acceleration mean square response, as well as their combination, as the cost function. For simplicity of presentation, the non-stationary excitation is modeled by an evolutionary stationary process in the paper. By means of three numerical examples for different types of non-stationary ground acceleration models, the results indicate that PSO can be used to find the optimum mass ratio, damper damping and tuning frequency of the non-stationary TMD system, and it is quite easy to be programmed for practical engineering applications. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Adaptive bang,bang control for the vibration control of structures under earthquakes

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 13 2003
    C. W. Lim
    Abstract An adaptive method based on the modified bang,bang control algorithm is proposed for the vibration control of structures subjected to unexpected severe seismic loads greater than the design loads. A hydraulic-type active mass damper was made and experiments were carried out in the laboratory using a one-story test structure and a five-story test structure with the active mass damper. Through numerical simulations and experiments it was confirmed that the proposed method works well to suppress the vibration of structures subjected to unexpected severe seismic loads greater than the design loads without causing any unstable situations. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    Statistical performance analysis of seismic-excited structures with active interaction control

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 7 2003
    Yunfeng Zhang
    Abstract This paper presents a statistical performance analysis of a semi-active structural control system for suppressing the vibration response of building structures during strong seismic events. The proposed semi-active mass damper device consists of a high-frequency mass damper with large stiffness, and an actively controlled interaction element that connects the mass damper to the structure. Through actively modulating the operating states of the interaction elements according to pre-specified control logic, vibrational energy in the structure is dissipated in the mass damper device and the vibration of the structure is thus suppressed. The control logic, categorized under active interaction control, is defined directly in physical space by minimizing the inter-storey drift of the structure to the maximum extent. This semi-active structural control approach has been shown to be effective in reducing the vibration response of building structures due to specific earthquake ground motions. To further evaluate the control performance, a Monte Carlo simulation of the seismic response of a three-storey steel-framed building model equipped with the proposed semi-active mass damper device is performed based on a large ensemble of artificially generated earthquake ground motions. A procedure for generating code-compatible artificial earthquake accelerograms is also briefly described. The results obtained clearly demonstrate the effectiveness of the proposed semi-active mass damper device in controlling vibrations of building structures during large earthquakes. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    Design of multiple tuned mass dampers by using a numerical optimizer

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 2 2005
    Nam Hoang
    Abstract A new method to design multiple tuned mass dampers (multiple TMDs) for minimizing excessive vibration of structures has been developed using a numerical optimizer. It is a very powerful method by which a large number of design variables can be effectively handled without imposing any restriction before the analysis. Its framework is highly flexible and can be easily extended to general structures with different combinations of loading conditions and target controlled quantities. The method has been used to design multiple TMDs for SDOF structures subjected to wide-band excitation. Some novel results have been obtained. To reduce displacement response of the structure, the optimally designed multiple TMDs have distributed natural frequencies and distinct damping ratios at low damping level. The obtained optimal configuration of TMDs was different from the earlier analytical solutions and was proved to be the most effective. A robustness design of multiple TMDs has also been presented. Robustness is defined as the ability of TMDs to function properly despite the presence of uncertainties in the parameters of the system. Numerical examples of minimizing acceleration structural response have been given where the system parameters are uncertain and are modeled as independent normal variates. It was found that, in case of uncertainties in the structural properties, increasing the TMD damping ratios along with expanding the TMD frequency range make the system more robust. Meanwhile, if TMD parameters themselves are uncertain, it is necessary to design TMDs for higher damping ratios and a narrower frequency range. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Tuned mass dampers for response control of torsional buildings

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 4 2002
    Mahendra P. Singh
    Abstract This paper presents an approach for optimum design of tuned mass dampers for response control of torsional building systems subjected to bi-directional seismic inputs. Four dampers with fourteen distinct design parameters, installed in pairs along two orthogonal directions, are optimally designed. A genetic algorithm is used to search for the optimum parameter values for the four dampers. This approach is quite versatile as it can be used with different design criteria and definitions of seismic inputs. It usually provides a globally optimum solution. Several optimal design criteria, expressed in terms of performance functions that depend on the structural response, are used. Several sets of numerical results for a torsional system excited by random and response spectrum models of seismic inputs are presented to show the effectiveness of the optimum designs in reducing the system response. Copyright © 2002 John Wiley & Sons, Ltd. [source]