Research on Restoring Force Model of Self-centering Unidirectional Friction Damper
ObjectiveTo enhance the self-centering ability of friction dampers, a self-centering unidirectional friction damper with adjustable frictional force was deeply studied. The objective of this study was to provide an accurate characterization of its hysteresis behavior.MethodsFirstly, the basic struct...
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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)
2025-01-01
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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.202500168 |
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| Summary: | ObjectiveTo enhance the self-centering ability of friction dampers, a self-centering unidirectional friction damper with adjustable frictional force was deeply studied. The objective of this study was to provide an accurate characterization of its hysteresis behavior.MethodsFirstly, the basic structure and working principle of damper were elaborated. Its core lies in achieving one-way energy dissipation via the friction device and self-centering through the reset device. Secondly, Based on an existing simplified model, by introducing the stiffness of both the damper cylinder and rod, the stiffness calculation methods for different operational phases were revised, and an improved restoring force model was developed. Thirdly, to verify the reliability of the restoring force model, two sets of experimental hysteresis data from self-centering unidirectional friction dampers with different distances between nuts and piston were used for comparison with the improved and simplified models. Finally, to determine the applicable conditions of the two restoring force models, a sensitivity test was performed on the two models. The relative deviation of maximum force (<italic>RD</italic><sub>f</sub>) and the relative deviation of energy dissipation per cycle (<italic>RD</italic><sub>w</sub>) were used as evaluation indicators. The analysis focused on the impact of changes in stiffness <italic>k</italic><sub>1</sub> and <italic>k</italic><sub>3</sub> on the two models.Results and Discussions 1)By comparing the maximum output force and energy dissipation per cycle at various displacement loading amplitudes under different distances between nuts and pistons, it was discovered that the improved model had a maximum relative error of 3.22% for the damper's maximum force and a relative error of 8.36% for energy dissipation. In contrast, the simplified model had relative errors of 3.32% and 10.38%, respectively. Therefore, the improved model proved more accurate in predicting the damper's hysteretic behavior. 2)When <italic>k</italic><sub>3</sub> was constant and <italic>k</italic><sub>1</sub> increased from 7.02 kN/mm to 28.08 kN/mm, <italic>RD</italic><sub>f</sub> showed no significant change. However, when <italic>k</italic><sub>1</sub> was constant and <italic>k</italic><sub>3</sub> increased from 45 kN/mm to 600 kN/mm, <italic>RD</italic><sub>f</sub> decreased, indicating an inverse relationship between <italic>RD</italic><sub>f</sub> and <italic>k</italic><sub>3</sub>. This means that as <italic>k</italic><sub>3</sub> increases, the maximum force predictions from the improved and simplified models become closer. Despite the different stiffness changes, <italic>RD</italic><sub>f</sub> remained below 5%, suggesting that the maximum force predictions from the two models were generally similar. 3)When <italic>k</italic><sub>3</sub> was constant and <italic>k</italic><sub>1</sub> increased from 7.02 kN/mm to 28.08 kN/mm, <italic>RD</italic><sub>w</sub> also increased, indicating that the relative <italic>RD</italic><sub>w</sub> calculated by the two restoring force models exhibits an increasing trend with <italic>k</italic><sub>1</sub>. Conversely, when <italic>k</italic><sub>1</sub> was fixed and <italic>k</italic><sub>3</sub> increased from 45 kN/mm to 600 kN/mm. <italic>RD</italic><sub>w</sub> decreased, showing an inverse relationship between <italic>RD</italic><sub>w</sub> and <italic>k</italic><sub>3</sub>. Indicating that the relative deviation of single-cycle energy dissipation calculated by the two models has a decreasing relationship with <italic>k</italic><sub>3</sub>. 4)To further investigate the impact of <italic>k</italic><sub>3</sub> and <italic>k</italic><sub>1</sub> on <italic>RD</italic><sub>w</sub>, a stiffness ratio <italic>ξ</italic> was defined. It was found that <italic>RD</italic><sub>w</sub> is proportional to <italic>ξ</italic>. When <italic>ξ</italic> exceeds 9.42%, <italic>RD</italic><sub>w</sub> surpasses 5%, indicating a significant discrepancy between the results of the simplified and improved models. In such cases, the improved model is recommended for energy dissipation calculation.ConclusionsBy comparing the maximum output force and energy dissipation per cycle at various displacement loading amplitudes under different distances between nuts and pistons, it was discovered that the improved model demonstrated higher consistency with experimental data. proving its superior capability in predicting damper hysteresis characteristics. The sensitivity test revealed that variations in damper stiffness parameters<italic>k</italic><sub>1</sub> and <italic>k</italic><sub>3</sub> exerted lesser impact on the relative deviation of maximum output force predictions between models, suggesting the simplified restoring force model allowed for a simpler prediction of the damper's maximum output force. However, significant effects of stiffness variations were observed on the relative deviation in energy dissipation per cycle, and the improved restoring force model enabled more accurate prediction of the damper's energy dissipation capacity. |
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| ISSN: | 2096-3246 |