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研究生:孫大衛
研究生(外文):Sun, David
論文名稱:複頻調質阻尼器對大跨度橋梁受風力擾動之制振分析
論文名稱(外文):Wind-Induced Vibration Control of Long-Span bridges By Multiple Tuned Mass Dampers
指導教授:林堉溢, 鄭啟明
指導教授(外文):Lin Yuh-Yi, Cheng Chii-Ming
學位類別:碩士
校院名稱:淡江大學
系所名稱:土木工程學系
學門:工程學門
學類:土木工程學類
論文種類:學術論文
論文出版年:1997
畢業學年度:85
語文別:中文
論文頁數:133
中文關鍵詞:大跨度橋梁顫振亂流效應複頻調質阻尼器制振折減率穩固度
外文關鍵詞:long-span bridgeflutterbuffetingmultiple TMDreduction ratiorobustness
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,斷面亦趨於細長化,因此橋梁受氣動力效應的影響逐漸增加,而其中又
以顫振現象 與亂流效應最為顯著。

在設計風速下,若橋梁受風力擾動所引發的振幅過大,將對行車的舒適性
、材料疲勞 的安全性造成影響,在不改變斷面形狀的條件下,可設置具
有質量、彈簧與阻尼的調 質阻尼器來減低振幅。

在本文的理論分析中,以單一方向(垂直向或扭轉向;非耦合型)制振的
複頻調質阻 尼器作為研究模型,將結構視為 1個自由度的運動,與N個
複頻調質阻尼器形成N+1個 自由度的運動模式,推導出運動方程式與轉
換函數,以散漫振動理論求出設置複頻調 質阻尼器後的位移動態反應。
本文分別針對垂直向、扭轉向的複頻調質阻尼器(MTMD) 進行分析。以其
對亂流效應的制振折減率,評估設計參數的影響,藉此對各項參數做 一
連串的交叉分析,瞭解參數彼此間的相關性與複頻調質阻尼器的制振特性
,證明MT MD的制振折減率與穩固度皆優於STMD。由上述之分析結果,提
出MTMD各項參數的建議 值,並對實際設計MTMD時提供設計方案與考慮因
素,最後以有效阻尼比來預估MTMD的 制振折減率。

調質阻尼器的制振效果如同增加結構之等值阻尼比,故本文利用複數特徵
值法,以數 值結果分析調質阻尼器對臨界風速的增幅,並提出影響最甚
的影響參數。
Developments of construction methods and improvements of
materials have led to the use of longer spans and more
slender sections in modern bridge design. Therefore, the
susceptibility of this type of bridges to wind excitation
becomes more significant. The most prominent aerodynamics on
bridges are known as flutter and buffeting. When buffeting
response is larger than the tolerable value at the design
wind speed, the response should be controlled by some
devices. Among the vibration control devices, MTMDs are recently
proposed and proven to be effective against harmonic loads.
Because wind loads are not harmonic, the effectiveness of
MTMD used in long-span bridges subjected to wind excitation
should be studied further.In general, the vertical or torsional
motion of long-span bridge is dominated by the structure''s
first mode in that direction. Hence, it is possible to model
the bridge as a SDOF system and each TMD of the MTMDs also as a
SDOF system. Then, the equations of motion can be formulated
based on the N+1 DOF system. And the dynamic response of the
bridge and TMDs are easily obtained by using of the transfer
functions. The
dynamic response reductions and the increase of the flutter
velocity due to the addition of the MTMDs on the bridge are
discussed. Through a parametric analysis, the design
properties of the MTMDs are studied and the design procedures
are proposed. The comparison of effectiveness between a
single TMD and the MTMD is also provided in this paper. Also,
the increase of the flutter velocity of the flexible bridge
due to the addition of MTMDs is discussed.

The results show that the MTMDs are more effective and more
robust than a single TMD against the vibration induced by
buffeting. The performance in torsional direction is
extremely well as the wind velocity approaches to the
flutter velocity.
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