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Investigation on seismic damping effect of an innovative amplified viscously damped outrigger for super high‑rise structures

Xue Jianyang, Zhang Wei, Luo Zheng, Qi Liangjie, Yan Sui

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e37, 2023

EN

AN innovative amplified viscously damped outrigger (AVDO) is newly proposed to improve the seismic damping effect of conventional viscousl damped outrigger (VDO) on super high-rise structures by mechanically increasing the displacement of the viscous damper (VD). To investigate the advantages of the damping effect on AVDO over VDO, the dynamic cyclic tests on VDO and AVDO were conducted to verify the feasibility of AVDO and superiority of AVDO over VDO. On this basis, six finite element models of a 258 m-high building with two types of damped outriggers placed at different heights were established and analyzed by dynamic time-history method. By comparing the seismic responses of numerical models, it is shown that upgrading VDO to AVDO can improve the damping efficiency of VDs and effectively expand the applicable damping placement in structural height, thus, the structure can achieve a better damping effect. An equivalent theoretical model of AVDO was established and validated by numerical analysis, which contributes to facilitating the modelling work and analysis of AVDO. However, experimental results showed that the outrigger deformation reduced the working displacement of VD seriously, indicating that the stiffness of the outrigger should be designed reasonably to withstand the damping force in motion. On this basis, the relationship between the working efficiency of VD and the stiffness ratio of outrigger to VD was derived and verified. To ensure the high work efficiency of the damper, the recommended stiffness limit of the outrigger supporting nonlinear VD was put forward, which fills a gap in the specification for practical applications.

2

Influence of the damping effect on the dynamic response of a plate

Borkowski Łukasz

Journal of Theoretical and Applied Mechanics

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2019

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Vol. 57 nr 1

263--272

EN

The subject of the research is analysis of the influence of the damping effect on the dynamic response of a plate. During the tests, the areas of dynamic stability and instability for the plate with and without damping are compared. Besides, exact analysis of the nature of the solution by applying criteria such as phase portraits, Poincar´e maps, FFT analysis, the largest Lyapunov exponents are carried out and found.

3

Acoustic characteristics of damped metamaterial plate with parallel attached resonators

Wang T., Sheng M. P., Guo Z. W., Qin Q. H.

Archives of Mechanics

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2017

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Vol. 69, nr 1

29--52

EN

An acoustic metamaterial consisting of a homogeneous damped plate with parallel attached resonators is presented. Theoretical analysis shows that the metamaterial plate can generate multiple resonant-type band gaps and the lower-bound frequency of each band gap coincides with the resonance frequencies of the resonators. The parallel arrangement of resonators, compared with the metamaterial plate with resonators attached in series reported by Peng et al. (2015), results in a wider second band gap with a lower edge, while the first band gap is almost the same, creating therefore an easier combination of the multiple band gaps into a wider one. It is noted that damping has a significant influence on the band gaps and the effective mass density (especially for the damping of resonators). Specifically, it can be concluded that damping cannot be neglected in practical engineering applications, damping in the material of the host plate can smooth and lower the responses in the whole frequency range, especially in the higher frequency range, and a high level of damping of resonators deactivates the effect of band gaps. Such weak/damped resonators actualise the metamaterial damping poorly, and rather tend only to contribute to the overall damping such as the damping of the host plate.

4

Active damping vibrations of the inertia input for the asymmetric shaft supported on the bearings lubricate liquid

Starczewski Z.

Mechanics and Mechanical Engineering

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2006

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Vol. 10, nr 1

126-137

EN

The paper discusses some possibility of the arising damp vibrations under inertia input for asymmetric rotor supported in the cylindrical slide bearing lubricated by electro fluid. It is shown that the effect of the electric field on the individual bearings junction makes it possible to achieve similar vibrations for both journals bearing although with strong asymmetry. The phenomenon discussed that increasing intensity of the electric field causes a reduction of the forced vibration but the self - excitation threshold moves in direction to the lower rotation speed.