| 摘要: | 本研究採用耦合離散元素法(Discrete Element Method, DEM)與有限元素法(Finite Element Method, FEM)及耦合離散元素法與多體動力學(Multibody Dynamics, MBD)模擬技術，分析具顆粒阻尼器的五層樓鋼架結構系統，並將其簡化為單自由度與多自由度系統模型，探討在不同的顆粒材料、顆粒粒徑、顆粒填充率、顆粒質量比與顆粒阻尼器安裝位置對具顆粒阻尼器鋼架結構系統動態反應行為的影響。本研究提出創新的DEM-MBD耦合模擬技術，作為爾後顆粒阻尼器的設計，同時節省大量的運算時間使其具有工程實際應用價值。本研究亦考慮單一頻率振盪(正弦波形)與隨機振盪(阪神大地震加速度歷時曲線波形)下對具顆粒阻尼器鋼架結構系統動態反應行為的影響。本研究設計四種基準測試，分別為FEM模型的單自由度彈簧質量系統基準測試、耦合DEM-FEM模型的顆粒撞擊平板恢復係數試驗、MBD模型的單與多自由度彈簧質量系統基準測試，驗證本研究建立DEM-FEM與DEM-MBD耦合模型的正確性。研究結果顯示: (1)在相同顆粒數量下，顆粒密度較大的材料，碰撞接觸力較大，減振效果愈佳；(2)顆粒總質量相同下，粒徑愈小的顆粒，顆粒與腔體的碰撞機率就愈大，使其減振效果愈佳；(3)顆粒填充率增加，減振效果也顯著的增加；(4)單自由度簡化模型與實際鋼架結構在實際地震波下具有相當一致的減振效果，證明單自由度簡化模型的合理性；(5)單自由度簡化模型與多自由度簡化模型在承受實際地震波下具有相當一致的動態行為，證明多自由度簡化模型的合理性；(6)在相同顆粒材料與顆粒粒徑下，顆粒質量比增加，顆粒數量就越多，能有更多的碰撞機率，減振效果也顯著增加；(7)顆粒阻尼器安裝位置愈高，鋼架結構樓層位移愈大，顆粒具有較大的速度與機率跟腔體接觸，顆粒阻尼器減振效果愈佳。;This study uses two-way coupling simulation techniques, discrete element method (DEM) with finite element method (FEM) and discrete element method with multibody dynamics (MBD), to analyze the dynamical behavior of a five-story steel frame with particle dampers. To facilitate the design of particle dampers, the simplified model into single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) is proposed. The effects of particle materials, particle sizes, particle filling ratios, particle mass ratios, and installation locations of the particle dampers on the dynamic response of steel frames are systematically explored. This study also considers two loading scenarios: harmonic excitation (sine waveform) and random excitation (Great Hanshin earthquake acceleration time history). Four benchmark tests are established to validate the proposed two-way coupling simulation models. These benchmark tests confirm the correctness of the developed DEM–FEM and DEM–MBD two-way coupled models.
Under the same number of particles, particles with higher material density generate larger contact forces upon collision, showing better vibration damping performances. For the same total particle mass, smaller particle sizes result in a higher collision frequency with the chamber walls, thus improving vibration damping effects. Increasing the particle filling ratio significantly enhances vibration damping effects. The SDOF simplified model exhibits vibration mitigation performance comparable to that of the actual steel frame under real earthquake excitation, confirming the rationality of the SDOF model. The SDOF and MDOF simplified models show highly consistent dynamic behavior under real earthquake excitation, validating the rationality of the MDOF model. For particles with identical material and diameter, increasing the particle mass ratio induces a greater number of particles and hence more collision events, significantly improving vibration damping performances. The higher the installation position of the particle damper, the larger the floor displacement of the steel frame, which imparts higher particle velocities and more frequent collisions with the chamber walls, resulting in improved vibration damping effects. |
