Experimental study of vibration mitigation of mast arm signal structures with particle-thrust damping based tuned mass damper

2019 ◽  
Vol 18 (1) ◽  
pp. 219-231 ◽  
Author(s):  
Yunfeng Zhang ◽  
Heng Liu
Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3319 ◽  
Author(s):  
Jijian Lian ◽  
Yue Zhao ◽  
Chong Lian ◽  
Haijun Wang ◽  
Xiaofeng Dong ◽  
...  

Offshore wind turbine (OWT) structures are highly sensitive to complex ambient excitations, especially extreme winds. To mitigate the vibrations of OWT structures under windstorm or typhoon conditions, a new eddy current with tuned mass damper (EC-TMD) system that combines the advantages of the eddy current damper and the tuned mass damper is proposed to install at the top of them. In the present study, the electromagnetic theory is applied to estimate the damping feature of the eddy current within the EC-TMD system. Then, the effectiveness of the EC-TMD system for vibration mitigation is demonstrated by small-scale tests. Furthermore, the EC-TMD system is used to alleviate structural vibrations of the OWT supported by composite bucket foundations (CBF) under extreme winds at the Xiangshui Wind Farm of China. It is found that the damping of the EC-TMD system can be ideally treated as having linear viscous damping characteristics, which are influenced by the gaps between the permanent magnets and the conductive materials as well as the permanent magnet layouts. Meanwhile, the RMS values of displacements of the OWT structure can be mitigated by 16% to 28%, and the acceleration can also be reduced significantly. Therefore, the excellent vibration-reducing performance of the EC-TMD system is confirmed, which provides meaningful guidance for application in the practical engineering of OWTs.


2009 ◽  
pp. n/a-n/a ◽  
Author(s):  
Min-Li Chang ◽  
Chi-Chang Lin ◽  
Jin-Min Ueng ◽  
Kai-Hsiang Hsieh ◽  
Jer-Fu Wang

2019 ◽  
Vol 9 (23) ◽  
pp. 5045 ◽  
Author(s):  
Qinhua Wang ◽  
Haoshuai Qiao ◽  
Dario De Domenico ◽  
Zhiwen Zhu ◽  
Zhuangning Xie

The beneficial mass-amplification effect induced by the inerter can be conveniently used in enhanced variants of the traditional Tuned Mass Damper (TMD), namely the Tuned Mass-Damper-Inerter (TMDI) and its special case of Tuned Inerter Damper (TID). In this paper, these inerter-based vibration absorbers are studied for mitigating the wind-induced response of high-rise buildings, with particular emphasis on a 340 m tall building analyzed as case study. To adopt a realistic wind-excitation model, the analysis is based on aerodynamic forces computed through experimental wind tunnel tests for a scaled prototype of the benchmark building, which accounts for the actual cross-section of the structure and the existing surrounding conditions. Mass and stiffness parameters are extracted from the finite element model of the primary structure. Performance-based optimization of the TMDI and the TID is carried out to find a good trade-off between displacement- and acceleration-response mitigation, with the installation floor being an explicit design variable in addition to frequency and damping ratio. The results corresponding to 24 different wind directions indicate that the best vibration mitigation is achieved with a lower installation floor of the TMDI/TID scheme than the topmost floor. The effects of different parameters of TMD, TMDI and TID on wind-induced displacement and acceleration responses and on the equivalent static wind loads (ESWLs) are comparatively evaluated. It is shown that the optimally designed TMDI/TID can achieve better wind-induced vibration mitigation than the TMD while allocating lower or null attached mass, especially in terms of acceleration response.


Author(s):  
Paul Kakou ◽  
Oumar Barry

Abstract Considerable attention has been recently given to electromagnetic resonant shunt tuned mass damper-inerter (EH-TMDI) for simultaneous vibration mitigation and energy harvesting. However, only linear structures have been investigated. Hence, in this paper, we aim at simultaneously achieving vibration mitigation and energy harvesting for nonlinear oscillators. To do so, we attach a nonlinear electromagnetic resonant shunt tuned mass damper-inerter (NEH-TMDI) to a single degree of freedom nonlinear oscillator (Duffing Oscillator). The nonlinear oscillator is coupled to the tuned mass damper via a linear and a nonlinear spring. Both the electromagnetic and the inerter devices are grounded on one side and connected to the nonlinear vibration absorber on the other side. This is done so to relax the trade off between energy harvesting and vibration suppression. The electromagnetic transducer is shunted to a resistor-inductor circuit. The governing equations of motion are derived using Newton’s method. Numerical simulations are carried out to examine the performance of the proposed NEH-TMDI. Comprehensive parametric analyses are conducted to identify the key design parameters that render the best performance of the NEH-TMDI. The results show that selected parameters offer regions were maximum energy dissipated and maximum energy harvested coincide. The findings are very promising and open a horizon of future opportunities to optimize the design of the NEH-TMDI for superior performance.


2017 ◽  
Vol 7 (9) ◽  
pp. 895 ◽  
Author(s):  
Junda Chen ◽  
Guangtao Lu ◽  
Yourong Li ◽  
Tao Wang ◽  
Wenxi Wang ◽  
...  

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