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RISS 인기검색어
- 검색키워드
- 저자 : Kunjie Rong (검색결과 5 건)
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Performance of a gas-spring tuned mass damper under seismic excitation
Kunjie Rong,Zheng Lu 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.2
A nonlinear gas-spring is integrated into the traditional tuned mass damper (TMD), leading to a novel gas-spring tuned mass damper (GSTMD) system, which can be used to mitigate the structural responses. To better couple the tuned mass damping system, a symmetrical combined gas-spring (SCGS) is presented based on a single gas-spring, and its mechanical properties are investigated through a case study. The design method of the gas-spring TMD is obtained, and its corresponding configuration parameters are calculated. The control performance and damping mechanism of the gas-spring TMD under the random excitation are studied by parameter analysis, and the reliability of the gas-spring TMD’s control performance is also discussed. The results show that the gas-spring TMD has a two-stage damping mechanism, and its working stage can change flexibly with the excitation intensity. Furthermore, the gas-spring TMD has excellent “Reconciling Control Performance”, which not only has a comparable control performance as the linear TMD, but also has significant advantages in working stroke, more importantly, the control performance and working stroke of the gas-spring TMD can reconcile with each other. Besides, the control performance of the proposed damper is insensitive to unpredictable seismic excitations, indicating that the gas-spring TMD has good reliability.
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Kunjie Rong,Xinghua Li,Zheng Lu,Siyuan Wu 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.87 No.2
To efficiently attenuate seismic responses of a structure, a novel pneumatic-driven active dynamic vibration absorber (PD-ADVA) is proposed in this study. PD-ADVA aims to realize closed-loop control using a simple and intuitive control algorithm, which takes the structure velocity response as the input signal and then outputs an inverse control force to primary structure. The corresponding active control theory and phase control mechanism of the system are studied by numerical and theoretical methods, the system’s control performance and amplitude-frequency characteristics under seismic excitations are explored. The capability of the proposed active control system to cope with frequency-varying random excitation is evaluated by comparing with the optimum tuning TMD. The analysis results show that the control algorithm of PD-ADVA ensures the control force always output to the structure in the opposite direction of the velocity response, indicating that the presented system does not produce a negative effect. The phase difference between the response of uncontrolled and controlled structures is zero, while the phase difference between the control force and the harmonic excitation is π, the theoretical and numerical results demonstrate that PD-ADVA always generates beneficial control effects. The PD-ADVA can effectively mitigate the structural seismic responses, and its control performance is insensitive to amplitude. Compared with the optimum tuning TMD, PD-ADVA has better control performance and higher system stability, and will not have negative effects under seismic wave excitations.
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A novel nonlinear gas-spring TMD for the seismic vibration control of a MDOF structure
Kunjie Rong,Zheng Lu 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.83 No.1
A nonlinear gas-spring tuned mass damper is proposed to mitigate the seismic responses of the multi-degree-offreedom (MDOF) structure, in which the nine-story benchmark model is selected as the controlled object. The nonlinear mechanical properties of the gas-spring are investigated through theoretical analysis and experiments, and the damper’s control parameters are designed. The control performance and damping mechanism of the proposed damper attached to the MDOF structure are systematically studied, and its reliability is also explored by parameter sensitivity analysis. The results illustrate that the nonlinear gas-spring TMD can transfer the primary structure’s vibration energy from the lower to the higher modes, and consume energy through its own relative movement. The proposed damper has excellent “Reconciling Control Performance”, which not only has a comparable control effect as the linear TMD, but also has certain advantages in working stroke. Furthermore, the control parameters of the gas-spring TMD can be determined according to the external excitation amplitude and the gas-spring’s initial volume.
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Temperature effect on seismic behavior of transmission tower-line system equipped with SMA-TMD
Li Tian,Juncai Liu,Canxing Qiu,Kunjie Rong 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.1
Transmission tower-line system is one of most critical lifeline systems to cities. However, it is found that the transmission tower-line system is prone to be damaged by earthquakes in past decades. To mitigate seismic demands, this study introduces a tuned-mass damper (TMD) using superelastic shape memory alloy (SMA) spring for the system. In addition, considering the dynamic characteristics of both tower-line system and SMA are affected by temperature change. Particular attention is paid on the effect of temperature variation on seismic behavior. In doing so, the SMA-TMD is installed into the system, and its properties are optimized through parametric analyses. The considered temperature range is from -40 to 40°C. The seismic control effect of using SMA-TMD is investigated under the considered temperatures. Interested seismic performance indices include peak displacement and peak acceleration at the tower top and the height-wise deformation. Parametric analyses on seismic intensity and frequency ratio were carried out as well. This study indicates that the nonlinear behavior of SMA-TMD is critical to the control effect, and proper tuning before application is advisable. Seismic demand mitigation is always achieved in this wide temperature range, and the control effect is increased at high temperatures.
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Seismic response control of transmission tower-line system using SMA-based TMD
Li Tian,Mengyao Zhou,Canxing Qiu,Haiyang Pan,Kunjie Rong 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.1
This study proposes a new shape memory alloy-tuned mass damper (SMA-TMD) and investigates the effectiveness of this damper in reducing and controlling the vibrations of a transmission tower-line system under various seismic excitations. Based on a practical transmission line system and considering the geometric nonlinearity of this system, the finite element (FE) software ANSYS is used to create an FE model of the transmission tower-line system and simulate the proposed SMA-TMD. Additionally, the parameters of the SMA springs are optimized. The effectiveness of a conventional TMD and the proposed SMA-TMD in reducing and controlling the vibrations of the transmission tower-line system under seismic excitations is investigated. Moreover, the effects of the ground motion intensity and frequency ratio on the reduction ratio (η) of the SMA-TMD are studied. The vibration reduction effect of the SMA-TMD under various seismic excitations is superior to that of the conventional TMD. Changes in the ground motion intensity and frequency ratio have a significant impact on the η of the SMA-TMD. As the ground motion intensity and frequency ratio increase, the η values of the SMA-TMD first increase and then decrease. Studying the vibration reduction effects of the SMA-TMD can provide a reference for the practical engineering application of this damper.
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