Apparent-weakening by adaptive passive stiffness shaping along the height of multistory building using negative stiffness devices and dampers for seismic protection

Nagarajaiah, Satish; Sen, Debarshi

doi:10.1016/j.engstruct.2020.110754

Cited by 34 publications

(21 citation statements)

References 41 publications

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“…Following that, Pasala et al 20 and Attary et al 21,22 implemented the ANSD to a SDOF building and bridge, respectively, and proved that the device can suppress both displacement and acceleration responses. Pasala et al, 6 Nagarajaiah and Sen 23 installed the ANSD on all floors of a building to suppress the large deformation of the first floor and reduce the seismic energy transmitted from the ground to the top. Wang et al 24 and Chen et al 25 replaced the gap-spring assembles on the ANSD with dashpots and linear positive stiffness elements to investigate the beneficial effects of negative stiffness on amplifying the stroke of dashpots.…”

Section: Introductionmentioning

confidence: 99%

A novel structural seismic protection system with negative stiffness and controllable damping

Askari

et al. 2021

Struct Control Health Monit

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In this paper, an innovative controllable negative stiffness system (CNSS) integrating adaptive negative stiffness and controllable damping characteristics is proposed to realise desirable vibration protection and improve adaptability, hence being effective to various earthquakes. The force-displacement relationship of the CNSS is derived as the forward model to describe its nonlinear properties. Three representative control algorithms, i.e., Linear Quadratic Regular (LQR) control, H∞ control and Sliding Mode (SM) control, are utilised for the CNSS to attain optimal control force. Based on the Takagi-Sugeno-Kang (TSK) Fuzzy inference system optimised by Non-Dominated Sorted Genetic Algorithm II (NSGAII), a novel inverse model is proposed accordingly to obtain input current according to the required control force and real-time system responses. To demonstrate the feasibility and efficiency of the CNSS for structural seismic protection, a numerical case study is conducted on a three-storey building model with CNSS installed on its first floor. Four scaled benchmark earthquakes are employed as excitations for the case study. Ten evaluation criteria are adopted to assess and verify the performance of the CNSS, and comparisons are made with that of uncontrolled and passive controlled systems. The numerical results indicate that the proposed CNSS can significantly improve the vibration control performance on all evaluation criteria simultaneously in comparison with the other two conventional systems. In addition to having good suppression effects on peak floor displacement and peak inter-storey drift, the CNSS with the SM controller demonstrates superior performance on mitigating peak structure shear and peak acceleration response of the first floor.

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Section: Introductionmentioning

confidence: 99%

A novel structural seismic protection system with negative stiffness and controllable damping

Askari

et al. 2021

Struct Control Health Monit

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“…The negative stiffness is often achieved using special materials or mechanisms, which generally include magnets, 9 inclined rods in series with horizontal springs, 10 Euler buckled beams, 11 n ‐layer scissor‐like structure (SLS), 12 and spring mechanisms such as tension springs 13 and planar springs 14 . Contributions in the identification and control of NSEs were made by previous studies 15–17 . Recently, they developed a semi‐active adjustable stiffness device (SASD) based on the combination of a damage detection method and the semi‐active control strategy 18 .…”

Section: Introductionmentioning

confidence: 99%

“…14 Contributions in the identification and control of NSEs were made by previous studies. [15][16][17] Recently, they developed a semi-active adjustable stiffness device (SASD) based on the combination of a damage detection method and the semi-active control strategy. 18 Adjustable template stiffness device (ATSD) has also been proposed as a nonlinear add-on stiffness-modification device for structural vibration mitigation.…”

Section: Introductionmentioning

confidence: 99%

“…Through linear equivalent models, Jan Hogsberg presents that adaptive control strategies with NSEs perform better than the corresponding optimal viscous damper 42 . Nagarajaiah and Sen 17 demonstrated the efficacy of deploying negative stiffness devices (NSDs) in conjunction with nonlinear dampers (NDs) on multistory structures for seismic response control through numerical simulations. Wei et al 43 innovatively established a vehicle–magneto‐rheological steel‐spring FST coupled dynamic model and theoretically proved that MR‐D with a modified bang–bang control strategy could effectively improve the low‐frequency vibration‐reduction of an FST.…”

Section: Introductionmentioning

confidence: 99%

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A theoretical vibration‐reduction effect analysis of the floating slab track supported by nonlinear variable stiffness isolators and semi‐active magneto‐rheological dampers

Zhao

Wei

Cheng

et al. 2021

Structural Contr & Hlth

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Nonlinear vibration control theory has resolved some bottleneck problems that cannot be solved by traditional linear vibration control theories. In this study, intelligent controllable magneto-rheological dampers (MR-Ds) and highstatic-low-dynamic variable stiffness vibration isolators (VS-VIs) are innovatively applied to a traditional steel-spring floating slab track (FST) to improve its low-frequency vibration-reduction effect. To determine the reasonable parameter group of the VS-VI and the parameter matching when used with MR-D, parameter groups were first preliminarily proposed through static and dynamic analyses of the equivalent single-degree-of-freedom (SDOF) model of the FST. A vertical vehicle-variable stiffness-magneto-rheological FST coupled dynamic model was established, and the parameter group was optimized based on safety and vibration-reduction analyses. The simulated results showed that the positive and negative stiffnesses were the key parameters that determined the stiffness nonlinearity level and dynamic support capacity of the VS-VI.Improving the positive stiffness is necessary to achieve a low-dynamic stiffness under no vehicle load and to ensure the millimeter-level dynamic displacement of the FST under vehicle load. An appropriate stiffness nonlinearity level can achieve a better vibration-reduction effect, and excessive nonlinearity level will not bring more significant improvements. The damping ratio in the dynamic analysis is a key parameter to prevent the jumping phenomenon, and the recommended value should not be less than 5%. Moreover, when the VS-VI and the MR-D were efficiently incorporated, a smaller MR damping force and larger displacement threshold could not only achieve a better vibrationreduction effect but also reduce the energy consumption.

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“…Meanwhile, we have witnessed new and exciting progress over the past decade in the suppression of stay cable vibrations by using novel vibration control techniques. For example, a variety of passive dampers with negative stiffness feature 23–27 were designed to imitate the mechanical behavior of active controllers in civil engineering applications 28–30 . Subsequently, the superior performance of different versions of negative stiffness dampers in stay cable vibration suppression was illustrated analytically and experimentally 21,31–37 .…”

Section: Introductionmentioning

confidence: 99%

Optimal design of tuned inerter dampers with series or parallel stiffness connection for cable vibration control

Shi

Wei

Lin

et al. 2020

Struct Control Health Monit

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Summary Inerter dampers (IDs) and other inerter‐based vibration absorbers have elicited growing interest for vibration mitigation of stay cables. This study systematically investigates the vibration mitigation mechanism of tuned IDs (TIDs) for stay cables based on a continuous cable model. A TID consists of an ID connected with a spring stiffness in series (TID‐S) or parallel (TID‐P). On the basis of systematical parametric analyses, the impact of stiffness in series or parallel connections is evaluated, and the interrelations among ID, TID‐S, and TID‐P are elaborated. Subsequently, a detailed tuning procedure is summarized. Two optimal tuning formulas are also obtained to facilitate the rapid design of TID‐S and TID‐P. According to the optimized results, the damping ratios contributed by ID, TID‐S, or TID‐P to a stay cable are essentially determined by the inertance value. When the inertance deviates from the optimal value, the performance of ID drops significantly, but this adverse effect can be mitigated by tuning the stiffness in TID‐S or TID‐P.

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Apparent-weakening by adaptive passive stiffness shaping along the height of multistory building using negative stiffness devices and dampers for seismic protection

Cited by 34 publications

References 41 publications

A novel structural seismic protection system with negative stiffness and controllable damping

A novel structural seismic protection system with negative stiffness and controllable damping

A theoretical vibration‐reduction effect analysis of the floating slab track supported by nonlinear variable stiffness isolators and semi‐active magneto‐rheological dampers

Optimal design of tuned inerter dampers with series or parallel stiffness connection for cable vibration control

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