Seismic Performance Analysis of Energy Dissipation Building with Non-preload Variable Friction Inerter Under Extremely Rare Earthquake
ObjectiveTraditional energy dissipation technologies provide an effective solution to mitigate the seismic responses of buildings. There are two types of energy dissipation devices based on their operational characteristics: velocity-dependent dampers and displacement-dependent dampers. Friction dam...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Editorial Department of Journal of Sichuan University (Engineering Science Edition)
2025-07-01
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| Series: | 工程科学与技术 |
| Subjects: | |
| Online Access: | http://jsuese.scu.edu.cn/thesisDetails#10.12454/j.jsuese.202300931 |
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| Summary: | ObjectiveTraditional energy dissipation technologies provide an effective solution to mitigate the seismic responses of buildings. There are two types of energy dissipation devices based on their operational characteristics: velocity-dependent dampers and displacement-dependent dampers. Friction dampers (FDs), as a category of displacement-dependent energy dissipation devices, exhibit several common advantages, such as good energy dissipation capacity, satisfactory mechanical performance, and ease of fabrication and installation. Therefore, they have received extensive attention from researchers in recent years. Buildings can require large damping forces under extremely rare or near-fault earthquake events, which necessitate that existing FDs apply a high preload to deliver sufficient reaction forces. However, introducing an excessive preload force can be impractical and uneconomical for current FDs. For example, the damping force of existing FDs can need to reach 1 000 kN for buildings subjected to a severe or near-fault earthquake event, resulting in a required preload force of 10 000 kN when the friction coefficient is assumed to be 0.1. In addition, FDs with a specified preload force still face durability issues such as cold bonding, cold solidification, and preload relaxation. Therefore, this study aims to develop a non-preload variable friction inerter (NVFI), which provides satisfactory damping force and significant energy dissipation without relying on preload force.MethodsThe proposed NVFI mainly consisted of a ball screw, rotational plate, friction plate, spring, and two thrust bearings. One terminal of the ball screw was fixed to the structure using an ear plate. The ball screw of the NVFI generated axial motion when the structure reciprocally shook under seismic earthquakes, and the springs were driven to reciprocal motion, resulting in a variable positive pressure of the friction plate. Therefore, the butterfly-shaped hysteretic behavior of the proposed NVFI was found based on the friction mechanism mentioned above. Then, the restoring force formula of the proposed NVFI was further established. Then, seismic performance mitigation of a single-degree-of-freedom (SDOF) system under different hazard levels was conducted to evaluate the effectiveness and advantages of the proposed NVFI quantitatively. A 5% damping SDOF system with a mass of 50 660 kg and elastic stiffness of 2 000 kN/m was adopted as the analytical model. A Bouc‒Wen elastoplastic model was employed in the SDOF system with a yield strength of 24 kN and post-elastic stiffness of 200 kN/m. The SDOF system with and without the proposed NVFI was considered and denoted as SDOF‒NVFI and SDOF, respectively. Three groups of different ground motion records, including far-field, near-fault pulse, and near-fault non-pulse ground motion records, were selected to perform the nonlinear dynamic analysis, and the peak ground acceleration (<italic>P</italic><sub>GA</sub>) scaled to multiple intensity levels was 0.2<italic>g</italic>, 0.4<italic>g</italic>, and 0.6<italic>g</italic> for design level earthquake (DLE), maximum considered earthquake (MCE), and extremely rare earthquake (ERE), respectively.Results and DiscussionsThe results illustrated that NVFI significantly reduced the displacement, velocity, and acceleration responses of the SDOF systems subjected to different earthquake records at different hazard levels. The average displacement reduction ratios were 46%, 56%, and 34% for the SDOF‒NVFI subjected to far-field, near-fault pulse, and near-fault non-pulse ground motions at the DLE hazard level, respectively. Similar reductions were also observed in the velocity and acceleration results. Compared to the results of the far-field and near-fault non-pulse ground motions, the displacement and velocity responses of the SDOF systems subjected to near-fault pulse ground motions were more effectively decreased using the proposed NVFI while maintaining a basically approximate acceleration mitigation effect. This is attributed to the fact that the proposed NVFI exhibits good energy dissipation capacity, which was induced by its unique friction mechanism. The satisfactory and variable friction force made the NVFI more suitable for buildings under seismic earthquakes with strong uncertainty, especially for near-fault pulse-such as earthquake events. On the other hand, the seismic input energy of the SDOF system was also decreased through the proposed NVFI. The seismic input energy of the SDOF‒NVFI system was less than 15 kJ at the MCE hazard level, while the seismic input energy of the SDOF system was greater than 24 kJ. This indicated that the fundamental frequency of the SDOF system can be effectively shifted from the dominant frequency of external disturbance by introducing the proposed NVFI, thus improving the overall performance of the structure. Finally, the parameter analysis of the SDOF‒NVFI systems considering different inertance-to-mass ratios was further performed to reveal the influence of the inerter mechanism from the proposed NVFI. The results illustrated that increasing the inertance-to-mass ratio of the proposed NVFI has a significant influence on the velocity and acceleration responses of the SDOF systems at the DLE hazard level while showing a slight but visible influence on the displacement response. Specifically, more than a 10% increase in the velocity and acceleration responses of the SDOF systems subjected to far-field ground motions at the DLE hazard level was observed, with the inertance-to-mass ratio increasing from 0.1 to 0.5.ConclusionsThe results indicated that the energy dissipation of the SDOF system primarily depends on the superior energy dissipation capacity of the NVFI due to the effectiveness of its variable friction mechanism, whereas the inerter serves only to transform the seismic input energy. |
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| ISSN: | 2096-3246 |