Nonlinear, seismic response spectra of smart sliding isolated structures with independently variable MR dampers and variable stiffness SAIVS system

Nagarajaiah, Satish; Mao, Y.H.; Saharabudhe, Sanjay

doi:10.12989/sem.2006.24.3.375

Cited by 8 publications

(8 citation statements)

References 20 publications

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“…(20) is commonly adopted in the numerical solution of a nonlinear system. With the above assumption, and by the numerical method of step-bystep integration, the discrete-time solution of Eq.…”

Section: Methods Of Numerical Simulationmentioning

confidence: 99%

“…A semiactive isolation system generally consists of a set of passive isolators and a certain type of semiactive control device, such as the MR damper [13,14], variable friction device [15,16], tuned interaction damper [17], variable stiffness device [18][19][20][21], etc. The function of the semiactive device, which is usually installed under the base of the structure, is to attenuate the seismic motion of the isolation system according to the current system response or excitation, so that the response of the superstructure can be mitigated.…”

Section: Introductionmentioning

confidence: 99%

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Stiffness controllable isolation system for near-fault seismic isolation

Lin

Kuo

2008

Engineering Structures

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Section: Methods Of Numerical Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stiffness controllable isolation system for near-fault seismic isolation

Lin

Kuo

2008

Engineering Structures

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“…Klingenberg [3] discuss the applications and challenges of MR fluid. MR fluids have a wide array of applications, including variable dampers [4][5][6], visco damper [7], and vibration damper [8], and Venkateswara Rao et al [9] studied the functional behavior of isotropic magnetorheological gels but MR fluids have distinct shortcomings. Liquid leakage can result in environmental contamination.…”

Section: Introductionmentioning

confidence: 99%

A Review of Magnetorheological Elastomers: Characterization Properties for Seismic Protection

2014

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Magnetorheological (MR) materials are belong to the group of smart materials that can be significantly altered in a controlled under the influence of an external stimulant which by changing their viscolesatic properties due to stress, pH level, moisture content, electric fields or in the case of MREs, magnetic fields. The MREs are interesting materials especially for the active stiffness and vibration control of structural systems. As a controllable stiffness element, MREs can offer innovative engineering solutions to various engineering challenges. Recently, they are being considered as new enabling components in active control systems, such as adaptive tuned vibration absorber and improving seismic protection base-isolated structures. The characteristic response will be influenced by many factors including; the elastomer matrix, the size, distribution, composition and percentage volume of the ferromagnetic particles, and whether the ferromagnetic particles are aligned in chains or randomly dispersed. A review is presented in this paper of the characteristic properties of magnetorheological elastomers and how these properties are affected by varying magnetic fields and the indicated compositional parameters. Besides describing the fundamental behavior of MREs, various applications of MREs for seismic protection are discussed and compared.

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“…Many control algorithms have been used to control MR dampers or semi‐active devices such as decentralized bang‐bang control (Feng and Shinozuka, 1990), the control method based on Lyapunov theory to minimize the rate of change of the Lyapunov function (Brogan, 1991), the method which decreases the total energy of the structure (McClamroch and Gavin, 1995), modified linear quadratic regulator (LQR) (Johnson and Erkus, 2007), and clipped‐optimal control (Dyke and Spencer, 1996). The effectiveness of using MR dampers combined with a semi‐active independently variable stiffness (SAIVS) to reduce the response of base isolated structure subjected to earthquakes was experimentally and analytically studied by Nagarajaiah et al (2006). A nonlinear tangential stiffness moving average control and Lyapunov based control algorithms were used to control SAIVS and MR dampers, respectively (Sahasrabudhe and Nagarajaiah, 2005; Nagarajaiah et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…The effectiveness of using MR dampers combined with a semi‐active independently variable stiffness (SAIVS) to reduce the response of base isolated structure subjected to earthquakes was experimentally and analytically studied by Nagarajaiah et al (2006). A nonlinear tangential stiffness moving average control and Lyapunov based control algorithms were used to control SAIVS and MR dampers, respectively (Sahasrabudhe and Nagarajaiah, 2005; Nagarajaiah et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Active and Semi‐active Adaptive Control for Undamaged and Damaged Building Structures Under Seismic Load

Bitaraf

Hurlebaus

Barroso

2011

Computer aided Civil Eng

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During the lifetime of a structural system, many severe events such as earthquakes and strong winds may impact the system and result in potential damage. To mitigate the structural vibration and damage during these extreme events, control devices such as active and semi‐active devices have received considerable attention because of their attractive characteristics. Active control devices are adaptable to any change and semi‐active devices have the capability of offering the reliability of passive devices and the versatility and adaptability of active devices. In this research, a direct‐adaptive‐control method is used to control the behavior of an undamaged and a damaged structure using semi‐active and active devices. In the adaptive control method, the controlled system is forced to behave like the model system which exhibits the desired behavior. The model of the adaptive control method is defined in a way to optimize the response of the controlled structure. The controller developed using this method can deal with changes that occur in the characteristics of the structure because it can modify its parameters during the control process. A magnetorheological (MR) damper is used as the semi‐active device in this study, whereas a hydraulic actuator is utilized as the active device to control the behavior of the structure. The performance of a three‐story building from the SAC project for the third generation of the control benchmark problem is studied by performing time–history analyses. The structure is subjected to different earthquakes and controlled by the direct adaptive control method. In the analysis of the structure, some stiffness reduction is assumed as a result of potential damage in the first story of the building. Also, the direct adaptive control strategy is used to optimize the response of the undamaged structure and to mitigate the damage impact on the performance of the controlled structure in the presence of noise for output measurements. The results of adaptive control method are compared with those of other control strategies. It is shown that the performance of the three‐story building is improved using the adaptive control method. By assessing the results of different control approaches, it is found that the adaptive control method works more effectively than other methods and semi‐active devices can provide reliable results.

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Nonlinear, seismic response spectra of smart sliding isolated structures with independently variable MR dampers and variable stiffness SAIVS system

Cited by 8 publications

References 20 publications

Stiffness controllable isolation system for near-fault seismic isolation

Stiffness controllable isolation system for near-fault seismic isolation

A Review of Magnetorheological Elastomers: Characterization Properties for Seismic Protection

Active and Semi‐active Adaptive Control for Undamaged and Damaged Building Structures Under Seismic Load

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